TI1 AMC7812 12-bit analog monitoring and control solution with multichannel adc, dacs, and temperature sensor Datasheet

AMC7812
www.ti.com
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
12-Bit ANALOG MONITORING AND CONTROL SOLUTION
with Multichannel ADC, DACs, and Temperature Sensors
Check for Samples: AMC7812
FEATURES
DESCRIPTION
• 12, 12-Bit DACs with Programmable Outputs:
◇ 0V to 5V
◇ 0V to 12.5V
• DAC Shutdown to User-Defined Level
• 12-Bit, 500kSPS ADC with 16 Inputs:
◇ 16 Single-Ended or
◇ Two Differential + 12 Single-Ended
• Two Remote Temperature Sensors:
◇ –40°C to +150°C, ±2°C Accuracy
• One Internal Temperature Sensor:
◇ –40°C to +125°C, ±2.5°C Accuracy
• Input Out-of-Range Alarms
• 2.5V Internal Reference
• Eight General-Purpose Input/Outputs
• Configurable I2C™-Compatible/ SPI™ Interface
with 5V/3V Logic
• Power-Down Mode
• Wide Temperature Range:
◇ –40°C to +105°C
• Small Packages: 9mm x 9mm QFN-64, and
10mm x 10mm HTQFP-64
The AMC7812 is a complete analog monitoring and
control solution that includes a 16-channel, 12-bit
analog-to-digital converter (ADC), twelve 12-bit
digital-to-analog converters (DACs), eight GPIOs, and
two remote/one local temperature sensor channels.
2345
The AMC7812 has an internal reference of +2.5V that
can configure the DAC output voltage to a range of
either 0V to +5V or 0V to +12.5V. An external
reference can be used as well. Typical power
dissipation is 95mW. The AMC7812 is ideal for
multichannel applications where board space, size,
and low power are critical.
The AMC7812 is available in either a 64-lead QFN or
HTQFP-64 PowerPAD™ package and is fully
specified over the –40°C to +105°C temperature
range.
For applications that require a different channel
count, additional features, or converter resolutions,
Texas Instruments offers a complete family of analog
monitor and control (AMC) products. Visit
http://www.ti.com/amc for more information.
ADC-REF-IN/CMP
Single-Ended/
Differential
1
RF Power Amplifier Control in Base Stations
Test and Measurement
Industrial Control
General Analog Monitoring and Control
Reference
(2.5V)
REF-OUT
REF-DAC
Trigger
DAC0-OUT
DAC-0
ADC
DAC1-OUT
DAC2-OUT
D1+
GPIO-5
D1-
GPIO-4
D2+
GPIO-7
DAC3-OUT
Control/Limits/Status
Registers
DAC4-OUT
DAC5-OUT
TEMP/GPIO
•
•
•
•
Single-Ended
APPLICATIONS
AMC7812
CH0
CH1
CH2
CH3
CH4
CH5
CH6
CH7
CH8
CH9
CH10
CH11
CH12
CH13
CH14
CH15
DAC6-OUT
Local
Temperature
Sensor
Remote
Temperature
Sensor
Driver
DAC7-OUT
DAC8-OUT
DAC9-OUT
DAC10-OUT
GPIO
D2-
GPIO-6
DAC11-OUT
DAC-11
GPIO-3
GPIO Controller
GPIO-0
LOAD-DAC
ALARM
Out-of-Range
Alarms
DACs Clear Logic
DAC-CLR-0
DAC-CLR-1
RESET
AGND3
AGND4
AGND1
AGND2
AVDD2
AVCC
AVDD1
A2
CS/A0
SDO/A1
SDI/SDA
SPI/I2C
IOVDD
CNVT
DVDD
DGND
SCLK/SCL
Serial Interface Register and Control
(SPI/I2C)
Control
Logic
DAV
1
2
3
4
5
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
SPI, QSPI are trademarks of Motorola, Inc.
I2C is a trademark of NXP Semiconductors.
MICROWIRE is a trademark of National Semiconductor.
All other trademarks are the property of their respective owners.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2011–2012, Texas Instruments Incorporated
AMC7812
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
www.ti.com
This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled with
appropriate precautions. Failure to observe proper handling and installation procedures can cause damage.
ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more
susceptible to damage because very small parametric changes could cause the device not to meet its published specifications.
PACKAGE/ORDERING INFORMATION (1)
PRODUCT
MAXIMUM
RELATIVE
ACCURACY
(LSB)
MAXIMUM
DIFFERENTIAL
NONLINEARITY
(LSB)
AMC7812
±1
±1
(1)
PACKAGELEAD
PACKAGE
DESIGNATOR
SPECIFIED
TEMPERATURE
RANGE
PACKAGE
MARKING
QFN-64
RGC
–40°C to +105°C
AMC7812
HTQFP-64
PAP
–40°C to +105°C
AMC7812
For the most current package and ordering information, see the Package Option Addendum at the end of this document, or visit the
device product folder at www.ti.com.
ABSOLUTE MAXIMUM RATINGS (1)
Over operating free-air temperature range, unless otherwise noted.
AMC7812
UNIT
AVDD to GND
–0.3 to +6
V
DVDD to GND
–0.3 to +6
V
IOVDD to GND
–0.3 to +6
V
AVCC to GND
–0.3 to +18
V
DVDD to DGND
–0.3 to +6
V
–0.3 to AVDD + 0.3
V
–0.3 to +6
V
D1+/GPIO-4, D1–/GPIO-5, D2+/GPIO-6, D2–/GPIO-7 to GND
–0.3 to AVDD + 0.3
V
Digital input voltage to DGND
–0.3 to IOVDD + 0.3
V
SDO and DAV to GND
–0.3 to IOVDD + 0.3
V
Operating temperature range
–40 to +105
°C
Storage temperature range
–40 to +150
°C
Analog input voltage to GND
ALARM, GPIO-0, GPIO-1, GPIO-2, GPIO-3, SCLK/SCL, and SDI/SDA to GND
Junction temperature range (TJ max)
ESD ratings
(1)
+150
°C
Human body model (HBM)
2.5
kV
Charged device model (CDM)
1.0
kV
Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device. Exposure to absolute
maximum conditions for extended periods may affect device reliability.
THERMAL INFORMATION
AMC7812
THERMAL METRIC (1)
RGC (QFN)
PAP (HTQFP)
64 PINS
64 PINS
θJA
Junction-to-ambient thermal resistance
24.1
33.7
θJCtop
Junction-to-case (top) thermal resistance
8.1
9.5
θJB
Junction-to-board thermal resistance
3.2
9.0
ψJT
Junction-to-top characterization parameter
0.1
0.3
ψJB
Junction-to-board characterization parameter
3.3
8.9
θJCbot
Junction-to-case (bottom) thermal resistance
0.6
0.2
(1)
2
UNITS
°C/W
For more information about traditional and new thermal metrics, see the IC Package Thermal Metrics application report, SPRA953.
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
AMC7812
www.ti.com
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
ELECTRICAL CHARACTERISTICS
At TA = –40°C to +105°C, AVDD = DVDD = 4.5V to 5.5V, AVCC = +15V, AGND = DGND = 0V, IOVDD = 2.7V to 5.5V, internal
2.5V reference, and the DAC output span = 0V to 5V, unless otherwise noted.
AMC7812
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
DAC PERFORMANCE
DAC DC ACCURACY
Resolution
12
INL
Relative accuracy
Measured by line passing through codes 020h
and FFFh
DNL
Differential nonlinearity
12-bit monotonic, Measured by line passing
through codes 020h and FFFh
TUE
Total unadjusted error
Offset error
±1
LSB
±1
LSB
TA = +25°C, DAC output = 5.0V
±10
mV
TA = +25°C, DAC output = 12.5V
±30
mV
TA = +25°C, DAC output = 0V to +5V,
code 020h
±2
mV
TA = +25°C, DAC output = 0V to +12.5V,
code 020h
±5
mV
±0.3
Offset error temperature coefficient
±1
External reference, output = 0V to +5V
Gain error
Bits
External reference, output = 0V to +12.5V
Gain temperature coefficient
ppm/°C
±0.025
±0.15
-0.15
±0.3
±2
%FSR
%FSR
ppm/°C
DAC OUTPUT CHARACTERISTICS
Output voltage range (1)
Output voltage settling time (2)
VREF = 2.5V, gain = 2
0
5
V
VREF = 2.5V, gain = 5
0
12.5
V
DAC output = 0V to +5V, code 400h to C00h, to
½ LSB, from CS rising edge,
RL = 2kΩ, CL = 200pF
3
Slew rate (2)
Short-circuit current (2)
Capacitive load stability (2)
DC output impedance
1.5
V/µs
30
mA
Source within 200mV of supply
+10
mA
Sink within 300mV of supply
-10
mA
Full-scale current shorted to ground
Load current
(2)
µs
RL = ∞
10
Code 800h
nF
Ω
0.3
Power-on overshoot
AVCC 0 to 5V, 2ms ramp
5
mV
Digital-to-analog glitch energy
Code changes from 7FFh to 800h, 800h to 7FFh
0.15
nV-s
Digital feedthrough
Device is not accessed
0.15
nV-s
Output noise
TA = +25°C, at 1kHz, code 800h, gain = 2,
excludes reference
f = 0.1Hz to 10Hz, excludes reference
81
nV/√Hz
8
µVPP
DAC REFERENCE INPUT
Reference voltage input range
REF-DAC pin
Input current (2)
VREF = 2.5V
1
2.6
V
170
µA
INTERNAL REFERENCE
Output voltage
TA = +25°C, REF-OUT pin
2.495
2.5
2.505
V
Ω
Output impedance
0.4
Reference temperature coefficient
10
Output current (sourcing/sinking)
±5
mA
260
nV/√Hz
13
µVPP
Output voltage noise
(1)
(2)
TA = +25°C, f = 1kHz
f = 0.1Hz to 10Hz
25
ppm/°C
The output voltage must not be greater than AVCC. See the DAC Output section for more details.
Sampled during initial release to ensure compliance; not subject to production testing.
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
3
AMC7812
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
www.ti.com
ELECTRICAL CHARACTERISTICS (continued)
At TA = –40°C to +105°C, AVDD = DVDD = 4.5V to 5.5V, AVCC = +15V, AGND = DGND = 0V, IOVDD = 2.7V to 5.5V, internal
2.5V reference, and the DAC output span = 0V to 5V, unless otherwise noted.
AMC7812
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
ADC PERFORMANCE
ADC DC ACCURACY (for AVDD = 5V)
Resolution
12
Bits
INL
Integral nonlinearity
±0.5
±1
LSB
DNL
Differential nonlinearity
±0.5
±1
LSB
±1
±3
LSB
Single-Ended Mode
Offset error
Offset error match
Gain error
±0.4
External reference
±1
Gain error match
LSB
±5
±0.4
LSB
LSB
Differential Mode
Gain error
External reference, 0V to (2 · VREF) mode, VCM =
2.5V
±2
±5
LSB
External reference, 0V to VREF mode,
VCM = 1.25V
±1
±5
LSB
Gain error match
Zero code error
±0.5
±1
±3
LSB
External reference, 0V to VREF mode,
VCM = 1.25V
±1
±3
LSB
Zero code error match
Common mode rejection
LSB
0V to (2 · VREF) mode, VCM = 2.5V
±0.5
DC, 0V to (2 · VREF) mode
LSB
67
dB
External single analog channel, auto mode
500
kSPS
External single analog channel, direct mode
167
kSPS
SAMPLING DYNAMICS
Conversion rate
Conversion time
(3)
External single analog channel
Autocycle update rate (3)
All 16 single-ended inputs enabled
Throughput rate
SPI clock 12MHz or greater, single analog
channel
2
µs
32
µs
500
kSPS
ANALOG INPUT (4)
Full-scale input voltage
Single-ended, 0V to VREF mode
0
VREF
V
Single-ended, 0V to (2 · VREF) mode
0
2 · VREF
V
–VREF
+VREF
V
–2 · VREF
2 · VREF
V
VIN+ – VIN-, fully-differential, 0V to VREF mode
VIN+ – VIN-, fully-differential, 0V to (2 · VREF)
mode
Absolute input voltage
GND - 0.2
Input capacitance (3)
DC input leakage current
AVDD + 0.2
40
Unselected ADC input
V
pF
±10
µA
ADC REFERENCE INPUT
Reference input voltage range
Input current
1.2
VREF = 2.5V
AVDD
145
V
µA
INTERNAL ADC REFERENCE BUFFER
Offset
(3)
(4)
4
TA = +25°C
±5
mV
Sampled during initial release to ensure compliance; not subject to production testing.
VIN+ or VIN– must remain within GND - 0.2V and AVDD + 0.2V. See Analog Inputs section.
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
AMC7812
www.ti.com
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
ELECTRICAL CHARACTERISTICS (continued)
At TA = –40°C to +105°C, AVDD = DVDD = 4.5V to 5.5V, AVCC = +15V, AGND = DGND = 0V, IOVDD = 2.7V to 5.5V, internal
2.5V reference, and the DAC output span = 0V to 5V, unless otherwise noted.
AMC7812
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
+125
°C
±2.5
°C
±1.5
°C
INTERNAL TEMPERATURE SENSOR
Operating range
–40
AVDD = 5V, TA = –40°C to +125°C
Accuracy
±1.25
AVDD = 5V, TA = 0°C to +100°C
Resolution
Per LSB
Conversion rate
External temperature sensors are disabled
0.125
°C
15
ms
EXTERNAL TEMPERATURE SENSOR (Using 2N3906 external transistor)
Operating range
Accuracy (5) (6)
Resolution
Limited by external diode
–40
AVDD = 5V, TA = 0°C to +100°C,
TD = –40°C to +150°C
AVDD = 5V, TA = –40°C to +100°C,
TD = –40°C to +150°C
Per LSB
Conversion rate per sensor
+150
°C
±1.5
°C
±2
°C
0.125
°C
With resistance cancellation
(RC bit = '1')
72
93
100
ms
Without resistance cancellation
(RC bit = '0')
33
44
47
ms
DIGITAL LOGIC: GPIO (7) (8) and ALARM
VIH
Input high voltage
VIL
Input low voltage
VOL
Output low voltage
IOVDD = +5V
2.1
0.3 + IOVDD
V
IOVDD = +3.3V
2.1
0.3 + IOVDD
V
IOVDD = +5V
–0.3
0.8
V
IOVDD = +3.3V
–0.3
0.8
V
IOVDD = +5V, sinking 5mA
0.4
V
IOVDD = +3.3V, sinking 2mA
0.4
V
High-impedance leakage
5
µA
10
pF
2.1
0.3 + IOVDD
V
High-impedance output capacitance
DIGITAL LOGIC: All Except SCL, SDA, ALARM, and GPIO
VIH
Input high voltage
VIL
Input low voltage
IOVDD = +5V
IOVDD = +3.3V
2.1
0.3 + IOVDD
V
IOVDD = +5V
–0.3
0.8
V
IOVDD = +3.3V
–0.3
0.8
V
±1
µA
5
pF
Input current
Input capacitance
VOH
Output high voltage
IOVDD = +5V, sourcing 3mA
4.8
IOVDD = +3.3V, sourcing 3mA
2.9
V
V
IOVDD = +5V, sinking 3mA
0.4
IOVDD = +3.3V, sinking 3mA
0.4
V
High-impedance leakage
±5
µA
High-impedance output capacitance
10
pF
VOL
(5)
(6)
(7)
(8)
Output low voltage
V
TD is the external diode temperature.
Auto conversion mode disabled
For pins GPIO0-3, the external pull up resistor must be connected to a voltage less than or equal to 5.5V.
For pins GPIO4-7, the external pull up resistor must be connected to a voltage less than or equal to AVDD.
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
5
AMC7812
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
www.ti.com
ELECTRICAL CHARACTERISTICS (continued)
At TA = –40°C to +105°C, AVDD = DVDD = 4.5V to 5.5V, AVCC = +15V, AGND = DGND = 0V, IOVDD = 2.7V to 5.5V, internal
2.5V reference, and the DAC output span = 0V to 5V, unless otherwise noted.
AMC7812
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
2
DIGITAL LOGIC: SDA, SCL (I C-Compatible Interface)
VIH
Input high voltage
VIL
Input low voltage
IOVDD = +5V
2.1
0.3 + IOVDD
V
IOVDD = +3.3V
2.1
0.3 + IOVDD
V
IOVDD = +5V
–0.3
0.8
V
IOVDD = +3.3V
–0.3
0.8
V
±5
µA
5
pF
V
Input current
Input capacitance
IOVDD = +5V, sinking 3mA
0
0.4
IOVDD = +3.3V, sinking 3mA
0
0.4
V
High-impedance leakage
±5
µA
High-impedance output capacitance
10
pF
100
250
µs
70
µs
100
250
µs
VOL
Output low voltage
TIMING REQUIREMENTS
Power-on delay
From AVDD , DVDD ≥ 2.7V and AVCC ≥ 4.5V to
normal operation
Power-down recovery time
from CS rising edge
Reset delay
Delay to normal operation from any reset
Convert pulse width
20
ns
Reset pulse width
20
ns
POWER-SUPPLY REQUIREMENTS
AVDD must be ≥ (VREF + 1.2V)
AVDD
AIDD
+2.7
AVDD and DVDD combined,
normal operation, no DAC load
7.9
AVDD and DVDD combined,
all blocks in power down
1.6
AVCC
+4.5
IVCC
AVCC, no load, DACs at code 800h
Power dissipation
Normal operation (9), AVDD = DVDD = 5V, AVCC =
15V
95
+5.5
V
12.5
mA
mA
+18
V
6.5
mA
120
mW
DVDD
+2.7
+5.5
V
IOVDD
+2.7
+5.5
V
–40
+105
°C
TEMPERATURE RANGE
Specified performance
(9)
6
No DAC load, all DACs at 800h and both ADCs at the fastest auto conversion rate
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
AMC7812
www.ti.com
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
FUNCTIONAL BLOCK DIAGRAM
Single-Ended
Single-Ended/
Differential
ADC-REF-IN/CMP
AMC7812
CH0
CH1
CH2
CH3
CH4
CH5
CH6
CH7
CH8
CH9
CH10
CH11
CH12
CH13
CH14
CH15
Reference
(2.5V)
REF-OUT
REF-DAC
Trigger
DAC0-OUT
DAC-0
ADC
DAC1-OUT
DAC2-OUT
D1+
GPIO-5
DAC3-OUT
Control/Limits/Status
Registers
DAC4-OUT
TEMP/GPIO
DAC5-OUT
D1D2+
GPIO-4
GPIO-7
DAC6-OUT
Local
Temperature
Sensor
Remote
Temperature
Sensor
Driver
DAC7-OUT
DAC8-OUT
DAC9-OUT
DAC10-OUT
GPIO
D2-
GPIO-6
DAC11-OUT
DAC-11
GPIO-3
GPIO Controller
GPIO-0
LOAD-DAC
ALARM
Out-of-Range
Alarms
DACs Clear Logic
DAC-CLR-0
DAC-CLR-1
RESET
AGND4
AGND3
AGND2
AGND1
AVDD2
AVDD1
AVCC
A2
SDO/A1
CS/A0
SDI/SDA
SCLK/SCL
IOVDD
CNVT
DGND
DVDD
SPI/I2C
Serial Interface Register and Control
(SPI/I2C)
Control
Logic
DAV
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
7
AMC7812
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
www.ti.com
PIN CONFIGURATION
DAC7-OUT
DAC6-OUT
AVDD2
AVDD1
52
51
50
49
AGND1
DAC8-OUT
54
53
AVCC1
AGND2
56
55
REF-DAC
REF-OUT
58
57
DAC10-OUT
DAC9-OUT
60
59
ALARM
DAC11-OUT
62
61
DGND2
DAC-CLR-1
64
63
RGC PACKAGE
QFN-64
(TOP VIEW)
RESET
1
48
CH15
DAV
2
47
CH14
CNVT
3
46
CH13
SDI/SDA
4
45
CH12
SCLK/SCL
5
44
CH11
DGND
6
43
CH10
IOVDD
7
42
CH9
DVDD
8
41
CH8
CS/A0
9
40
CH7
SDO/A1
10
39
CH6
A2
11
38
CH5
SPI/I2C
12
37
CH4
GPIO-0
13
36
CH3
GPIO-1
14
35
CH2
GPIO-2
15
34
CH1
GPIO-3
16
33
CH0
29
30
31
32
D1-/GPIO-4
D1+/GPIO-5
ADC-REF-IN/CMP
ADC-GND
27
28
D2-/GPIO-6
D2+/GPIO-7
25
26
DAC1-OUT
DAC0-OUT
23
24
AVCC2
DAC2-OUT
21
22
AGND4
AGND3
19
20
DAC4-OUT
DAC5-OUT
DAC3-OUT
17
18
DAC-CLR-0
AMC7812
8
DAC7-OUT
DAC6-OUT
AVDD2
AVDD1
52
51
50
49
AGND1
DAC8-OUT
54
53
AVCC1
AGND2
56
55
REF-DAC
REF-OUT
58
57
DAC10-OUT
DAC9-OUT
60
59
ALARM
DAC11-OUT
62
61
DGND2
DAC-CLR-1
64
63
PAP PACKAGE
HTQFP-64
(TOP VIEW)
RESET
1
48
CH15
DAV
2
47
CH14
CNVT
3
46
CH13
SDI/SDA
4
45
CH12
SCLK/SCL
5
44
CH11
DGND
6
43
CH10
IOVDD
7
42
CH9
DVDD
8
41
CH8
CS/A0
9
40
CH7
SDO/A1
10
39
CH6
A2
11
38
CH5
SPI/I2C
12
37
CH4
GPIO-0
13
36
CH3
GPIO-1
14
35
CH2
GPIO-2
15
34
CH1
GPIO-3
16
33
CH0
31
32
ADC-REF-IN/CMP
Submit Documentation Feedback
ADC-GND
29
30
D1-/GPIO-4
D1+/GPIO-5
27
28
D2-/GPIO-6
D2+/GPIO-7
25
26
DAC1-OUT
DAC0-OUT
23
24
AVCC2
DAC2-OUT
21
22
AGND4
AGND3
19
20
DAC4-OUT
DAC5-OUT
DAC3-OUT
17
18
DAC-CLR-0
AMC7812
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
AMC7812
www.ti.com
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
PIN DESCRIPTIONS
PIN (QFN / HTQFP)
DESCRIPTION
NO.
NAME
1
RESET
2
DAV
3
CNVT
4
SDI/SDA
5
SCLK/SCL
6
DGND
Digital ground
7
IOVDD
Interface power supply
8
DVDD
Digital power supply (+3V to +5V). Must be the same value as AVDD.
9
CS/A0
Chip select signal for SPI when the SPI/I2C pin is high. Slave address selection A0 for I2C when the SPI/I2C
pin is low.
10
SDO/A1
11
A2
12
SPI/I2C
13
GPIO-0
14
GPIO-1
15
GPIO-2
16
GPIO-3
Reset input, active low. Logic low on this pin causes the device to perform a hardware reset.
Data available indicator, active low output. In direct mode, the DAV pin goes low (active) when the conversion
ends. In auto mode, a 1µs pulse (active low) appears on this pin when a conversion cycle finishes (see the
Primary ADC Operation and Registers sections for details). DAV stays high when deactivated.
External conversion trigger, active low. The falling edge starts the sampling and conversion of the ADC.
Serial interface data. SDI for the serial peripheral interface (SPI) when the SPI/I2C pin is high. SDA for I2C
when the SPI/I2C pin is low.
Serial clock input of the main serial interface. SPI clock when the SPI/I2C pin is high; I2C clock when the
SPI/I2C pin is low.
SDO for SPI when the SPI/I2C pin is high. Slave address selection A1 for I2C when the SPI/I2C pin is low.
Slave address selection A2 for I2C when the SPI/I2C pin is low.
Interface selection pin. Digital input. When this pin is tied to IOVDD, the SPI is enabled and the I2C interface is
disabled. When this pin is tied to ground, the SPI is disabled and the I2C interface is enabled.
General-purpose digital input/output. This pin is a bidirectional open-drain, digital input/output, and requires an
external pull-up resistor. See the General Purpose Input/Output Pins section for more details.
DAC clear control signal, digital input, active low. When low, all DACs associated with the DAC-CLR-0 pin enter
a clear state, the DAC Latch is loaded with predefined code, and the output is set to the corresponding level.
However, the DAC-Data Register does not change. When the DAC goes back to normal operation, the DAC
Latch is loaded with the previous data from the DAC-Data Register and the output returns to the previous level,
regardless of the status of the SLDAC-n bit. When this pin is high, the DACs are in normal operation.
17
DAC-CLR-0
18
DAC5-OUT
19
DAC4-OUT
20
DAC3-OUT
21
AGND4
22
AGND3
23
AVCC2
24
DAC2-OUT
25
DAC1-OUT
26
DAC0-OUT
27
D2–/GPIO-6
Remote sensor D2 negative input when D2 enabled; GPIO-6 when D2 disabled. Pull-up required for output.
28
D2+/GPIO-7
Remote sensor D2 positive input when D2 enabled; GPIO-7 when D2 disabled. Pull-up required for output.
29
D1–/GPIO4
Remote sensor D1 negative input when D1 enabled; GPIO-6 when D1 disabled. Pull-up required for output.
30
D1+/GPIO-5
Remote sensor D1 positive input when D1 enabled; GPIO-7 when D1 disabled. Pull-up required for output.
31
ADC-REF-IN/CMP
32
ADC-GND
3348
CH0 to CH15
49
AVDD1
50
AVDD2
51
DAC6-OUT
52
DAC7-OUT
53
DAC8-OUT
Output of DAC channels 3, 4, and 5
Analog ground
Positive analog power for DAC0-OUT, DAC1-OUT, DAC2-OUT, DAC3-OUT, DAC4-OUT, DAC5-OUT, must be
tied to AVCC1
Output of DAC channels 0, 1, and 2
External ADC reference input when external VREF is used to drive ADC. Compensation capacitor connection
(connect 4.7µF capacitor between this pin and AGND) when Internal VREF is used to drive ADC.
ADC ground. Must be connected to AGND.
Analog inputs of channel 0 to 15. CH4 to CH15 are single-ended. CH0, CH1, CH2, and CH3 can be
programmed as differential or single-ended.
Positive analog power supply
Output of DAC channels 6, 7, and 8
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
9
AMC7812
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
www.ti.com
PIN DESCRIPTIONS (continued)
PIN (QFN / HTQFP)
DESCRIPTION
NO.
NAME
54
AGND1
55
AGND2
56
AVCC1
57
REF-OUT
Internal reference output
58
REF-DAC
DAC reference Input
59
DAC9-OUT
60
DAC10-OUT
61
DAC11-OUT
62
ALARM
63
DAC-CLR-1
64
DGND2
10
Analog ground
Positive analog power for DAC6-OUT, DAC7-OUT, DAC8-OUT, DAC9-OUT, DAC10-OUT, DAC11-OUT, must
be tied to AVCC2
Output of DAC channels 9, 10, and 11
Global alarm. Open drain output. External 10kΩ pull-up resistor required. This pin goes low (active) when one
(or more) of the analog channels are out of range.
DAC clear control signal, digital input, active low. When low, all DACs associated with the DAC-CLR-1 pin enter
a clear state, the DAC Latch is loaded with predefined code, and the output is set to the corresponding level.
However, the DAC-Data Register does not change. When the DAC goes back to normal operation, the DAC
Latch is loaded with the previous data from the DAC-Data Register and the output returns to the previous level,
regardless of the status of the SLDAC-n bit. When this pin is high, the DACs are in normal operation.
Digital ground
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
AMC7812
www.ti.com
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
I2C-COMPATIBLE TIMING DIAGRAMS
S
Sr
P
S
SDA
tSU, STA
tSU, DAT
tBUF
tHD, STA
tHD, DAT
tLOW
SCL
tSU, STO
tHIGH
tHD,STA
tR
tF
S = START Condition
Sr = Repeated START Condition
P = STOP Condition
= Resistor Pull-Up
Figure 1. Timing for Standard and Fast Mode Devices on the I2C Bus
TIMING CHARACTERISTICS: SDA and SCL for Standard and Fast Modes (1)
At –40°C to +105°C, AVDD = DVDD = 4.5V to 5.5V, AGND = DGND = 0V, and IOVDD = 2.7V to 5.5V, unless otherwise noted.
STANDARD
MODE
PARAMETER
FAST
MODE
MIN
MAX
MIN
MAX
UNIT
0
100
0
400
kHz
Low period of the SCL clock
4.7
—
1.3
—
ms
tHIGH
High period of the SCL clock
4.0
—
0.6
—
ms
tSU, STA
Set-up time for a repeated start condition
4.7
—
0.6
—
ms
tHD, STA
Hold time (repeated) start condition. After this
period, the first clock pulse is generated
4..0
—
0.6
—
ms
tSU, DAT
Data set-up time
250
—
100
—
ns
tHD, DAT
Data hold time: for I2C-bus devices
0
3.45
0
0.9
ms
tSU, STO
Set-up time for stop condition
4.0
—
0.6
—
ms
tR
Rise time of both SDA and SCL signals
—
1000
20 + 0.1CB (2)
300
ns
tF
Fall time of both SDA and SCL signals
—
300
20 + 0.1CB (2)
300
ns
tBUF
Bus free time between a stop and start condition
4.7
—
1.3
—
ms
CB
Capacitive load for each bus line
—
400
—
400
pF
tSP
Pulse width of spike suppressed
NA
NA
0
50
ns
fSCL
SCL clock frequency
tLOW
(1)
(2)
All values refer to VIHmin and VILmax levels.
CB = total capacitance of one bus line in pF.
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
11
AMC7812
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
www.ti.com
Sr
Sr
P
tFDA
tRDA
SDA
tHD, DAT
tSU, STA
tHD, STA
tSU, STO
tSU, DAT
SCL
tFCL
tRCL1(1)
tHIGH
tLOW
tRCL1(1)
tRCL
tLOW
tHIGH
= Current Source Pull-Up
= Resistor Pull-Up
(1)
Sr = Repeated START Condition
P = STOP Condition
First rising edge of the SCL signal after Sr and after each acknowledge bit.
Figure 2. Timing for High-Speed (Hs) Mode Devices on the I2C Bus
TIMING CHARACTERISTICS: SDA and SCL for Hs Mode (1)
At –40°C to +105°C, AVDD = 4.5V to 5.5V, DVDD = 2.7V to 5.5V, AGND = DGND = 0V, and IOVDD = 2.7V to 5.5V, unless
otherwise noted.
CB = 10pF to 100pF
PARAMETER
CB = 400pF
MIN
MAX
MIN
MAX
UNIT
0
3.4
0
1.7
MHz
fSCL
SCL clock frequency
tSU, STA
Setup time for (repeated) start condition
160
—
160
—
ns
tHD, STA
Hold time (repeated) start condition
160
—
160
—
ns
tLOW
Low period of the SCL clock
160
—
320
—
ns
tHIGH
High period of the SCL clock
60
—
120
—
ns
tSU, DAT
Data setup time
10
—
10
—
ns
tHD, DAT
Data hold time
0
70
0
150
ns
tRCL
Rise time of SCL signal
10
40
20
80
ns
tRCL1
Rise time of SCL signal after a repeated start condition
and after an acknowledge bit
10
80
20
160
ns
tFCL
Fall time of SCL signal
10
40
20
80
ns
tRDA
Rise time of SDA signal
10
80
20
160
ns
tFDA
Fall time of SDA signal
10
80
20
160
ns
tSU, STO
Set-up time for stop condition
160
—
160
—
ns
10
100
—
400
pF
0
10
0
10
ns
CB
tSP
(1)
(2)
12
(2)
Capacitive load for SDA and SCL lines
Pulse width of spike suppressed
All values refer to VIHmin and VILmax levels.
For bus line loads where CB is between 100pF and 400pF, the timing parameters must be linearly interpolated.
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
AMC7812
www.ti.com
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
SPI TIMING DIAGRAMS
t8
t10
t4
CS
t1
t7
t3
SCLK
t2
tR
tF
t5
SDI
t6
Bit 23
Bit 0
Bit 1
-- Don’t Care
Bit 23 = MSB
Figure 3. SPI Single-Chip Write Operation
t1
t7
t4
CS
t1
SCLK
t3
t2
tF
t5
t6
Bit 22
Bit 23
SDI
tR
Bit 0
Bit 23
Read Command
Bit 22
t9
SDO
Bit 1
Bit 0
Any Command
Bit 23
Bit 22
Bit 1
Bit 0
Data Read from the Register Selected
in the Previous Read Operation
Figure 4. SPI Single-Chip Read Operation
t8
t4
CS
t1
SCLK
t3
t2
tF
t5
SDI
t7
t6
Bit 23 (A)
tR
(Command to B)
(Command to A)
Bit 0 (A)
Bit 23 (B)
Bit 0 (B)
t9
Bit 23 (A)
SDO
Bit 0 (A)
Figure 5. Daisy-Chain Operation: Two Devices
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
13
AMC7812
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
www.ti.com
TIMING CHARACTERISTICS: SPI Bus (1)
At –40°C to +105°C, AVDD = DVDD = 4.5V to 5.5V, AGND = DGND = 0V, and IOVDD = 3.0V to 5.5V, unless otherwise noted.
LIMIT AT TMIN, TMAX
PARAMETER
MIN
MAX
UNIT
50
MHz
fSCLK
Clock frequency
t1
SCLK cycle time
20
ns
t2
SCLK high time
8
ns
t3
SCLK low time
8
ns
t4
CS falling edge to SCLK rising edge setup time
5
ns
t5
Input data setup time
5
ns
t6
Input data hold time
4
ns
t7
SCLK falling edge to CS rising edge
10
ns
t8
Minimum CS high time
30
ns
t9
Output data valid time
15
ns
t10
CS rising to next SCLK rising edge
3
ns
(1)
14
Specified by design; not production tested.
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
AMC7812
www.ti.com
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
TYPICAL CHARACTERISTICS: DAC
At +25°C, unless otherwise noted.
LINEARITY ERROR vs CODE
1
0.8
0.8
0.6
0.6
0.4
0.4
0.2
0.2
INL (LSB)
DNL (LSB)
DIFFERENTIAL LINEARITY ERROR vs CODE
1
0
−0.2
−0.4
−0.6
TA = −40°C
Gain = 2
VREF = 2.5V, Internal
−0.8
0
512
1024
1536
2048
Code
2560
3072
3584
−1
4096
0
512
1024
2560
3072
DIFFERENTIAL LINEARITY ERROR vs CODE
LINEARITY ERROR vs CODE
1
0.8
0.6
0.6
0.4
0.4
0.2
0.2
0
−0.2
−0.4
3584
4096
0
−0.2
−0.4
−0.6
−0.6
TA = +25°C
Gain = 2
VREF = 2.5V, Internal
−0.8
0
512
1024
1536
2048
Code
2560
3072
3584
TA = +25°C
Gain = 2
VREF = 2.5V, Internal
−0.8
−1
4096
0
512
1024
Figure 8.
1536
2048
Code
2560
3072
3584
4096
Figure 9.
DIFFERENTIAL LINEARITY ERROR vs CODE
LINEARITY ERROR vs CODE
1
1
0.8
0.8
0.6
0.6
0.4
0.4
0.2
0.2
INL (LSB)
DNL (LSB)
2048
Code
Figure 7.
1
0
−0.2
−0.4
0
−0.2
−0.4
−0.6
TA = +105°C
Gain = 2
VREF = 2.5V, Internal
−0.8
−1
1536
Figure 6.
0.8
−1
TA = −40°C
Gain = 2
VREF = 2.5V, Internal
−0.8
INL (LSB)
DNL (LSB)
−0.2
−0.4
−0.6
−1
0
0
512
1024
1536
2048
Code
2560
3072
3584
4096
−0.6
TA = +105°C
Gain = 2
VREF = 2.5V, Internal
−0.8
−1
0
Figure 10.
512
1024
1536
2048
Code
2560
3072
3584
4096
Figure 11.
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
15
AMC7812
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
www.ti.com
TYPICAL CHARACTERISTICS: DAC (continued)
At +25°C, unless otherwise noted.
LINEARITY ERROR vs CODE
1
0.8
0.8
0.6
0.6
0.4
0.4
0.2
0.2
INL (LSB)
DNL (LSB)
DIFFERENTIAL LINEARITY ERROR vs CODE
1
0
−0.2
−0.4
−0.4
−0.6
−0.6
TA = +25°C
Gain = 5
VREF = 2.5V, Internal
−0.8
−1
0
−0.2
0
512
1024
1536
2048
Code
2560
3072
3584
TA = +25°C
Gain = 5
VREF = 2.5V, Internal
−0.8
−1
4096
0
512
1024
1536
Figure 12.
1
0.8
0.8
0.6
0.6
INL (LSB)
DNL (LSB)
0
DNL Min
−0.4
INL Max
0.2
0
−0.2
−0.6
Gain = 2
VREF = 2.5V, Internal
−0.8
−25
−10
5
20
35
50
65
80
95
INL Min
−0.8
−1
−40
110
−25
−10
5
Gain = 2
VREF = 2.5V, Internal
20
TA (°C )
0.8
0.8
0.6
0.6
0.4
0.4
DNL Max
0.2
INL (LSB)
DNL (LSB)
1
0
−0.2
DNL Min
95
110
INL Max
0.2
0
−0.2
INL Min
−0.6
Gain = 5
VREF = 2.5V, Internal
−0.8
5
80
−0.4
−0.6
−10
65
LINEARITY ERROR vs TEMPERATURE
1
−25
50
Figure 15.
DIFFERENTIAL LINEARITY ERROR vs TEMPERATURE
−0.4
35
TA (°C )
Figure 14.
20
35
50
65
80
95
110
Gain = 5
VREF = 2.5V, Internal
−0.8
−1
−40
TA (°C )
−25
−10
5
20
35
50
65
80
95
110
TA (°C )
Figure 16.
16
4096
−0.4
−0.6
−1
−40
3584
0.4
DNL Max
0.2
−1
−40
3072
LINEARITY ERROR vs TEMPERATURE
1
−0.2
2560
Figure 13.
DIFFERENTIAL LINEARITY ERROR vs TEMPERATURE
0.4
2048
Code
Figure 17.
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
AMC7812
www.ti.com
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
TYPICAL CHARACTERISTICS: DAC (continued)
At +25°C, unless otherwise noted.
DIFFERENTIAL LINEARITY ERROR vs CODE
LINEARITY ERROR vs CODE
1
1
Ch0
Ch1
Ch2
Ch3
0.8
Ch8
Ch9
Ch10
Ch11
0.6
0.4
0.4
0.2
0.2
0
−0.2
−0.4
Ch3
Ch4
Ch5
0
0
512
1024
1536
2048
Code
2560
3072
3584
TA = +25°C
Gain = 2
VREF = 2.5V, Internal
−0.8
−1
4096
0
512
1024
1536
Figure 18.
GAIN ERROR
2560
3072
3584
4096
GAIN ERROR
60
TA = +25°C
Gain = 2
10884 Channels
TA = +25°C
Gain = 5
10368 Channels
50
Population (%)
40
30
20
10
40
30
20
Figure 20.
GAIN ERROR vs TEMPERATURE
0.2
Gain Error (%FSR)
0.1
0.05
0
−0.05
−0.1
Gain = 2
VREF = 2.5V, Internal
5
20
35
0.3
0.22
0.26
0.18
0.1
0.14
0.02
0.06
GAIN ERROR vs TEMPERATURE
0.3
−10
-0.02
Figure 21.
0.15
−25
-0.1
Gain Error (%FSR)
Gain Error (%FSR)
−0.15
−40
-0.06
-0.14
-0.22
-0.18
-0.3
0
0.15
0.11
0.13
0.09
0.05
0.07
0.01
0.03
-0.01
-0.03
-0.05
-0.07
-0.11
-0.09
-0.13
-0.15
10
-0.26
Population (%)
2048
Code
Figure 19.
50
Gain Error (%FSR)
Ch9
Ch10
Ch11
−0.2
−0.6
TA = +25°C
Gain = 2
VREF = 2.5V, Internal
−0.8
0
Ch6
Ch7
Ch8
−0.4
−0.6
−1
Ch0
Ch1
Ch2
0.8
INL (LSB)
DNL (LSB)
0.6
Ch4
Ch5
Ch6
Ch7
50
65
80
95
110
Gain = 5
VREF = 2.5V, Internal
0.1
0
−0.1
−0.2
−0.3
−40
TA (°C )
−25
−10
5
20
35
50
65
80
95
110
TA (°C )
Figure 22.
Figure 23.
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
17
AMC7812
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
www.ti.com
TYPICAL CHARACTERISTICS: DAC (continued)
At +25°C, unless otherwise noted.
GAIN ERROR vs SUPPLY
0.3
0.1
0.2
Gain Error (%FSR)
0.05
0
−0.05
0.1
0
−0.1
TA = +25°C
Gain = 2
VREF = 2.5V, Internal
−0.1
−0.15
4.5
6
7.5
9
10.5 12
AVCC (V)
13.5
15
16.5
TA = +25°C
Gain = 5
VREF = 2.5V, Internal
−0.2
−0.3
18
12
13
14
Figure 24.
OFFSET VOLTAGE
17
18
OFFSET VOLTAGE
35
Offset Error (mV)
Offset Error (mV)
Figure 26.
Figure 27.
OFFSET VOLTAGE vs TEMPERATURE
1.4
1.6
1
1.2
0.8
0.4
0
0.2
-0.2
-0.6
-1
-0.8
0.6
0.5
0.4
0.3
0.2
0
0
0.1
0
-0.1
5
-0.3
5
-0.2
10
-0.5
10
-1.2
15
-1.4
15
20
-1.6
Population (%)
25
20
-0.4
TA = +25°C
Gain = 5
VREF = 2.5V, Internal
Code = 020h
10884 Channels
30
0.6
TA = +25°C
Gain = 2
VREF = 2.5V, Internal
Code = 020h
2220 Channels
-0.6
Population (%)
25
16
Figure 25.
35
30
15
AVCC (V)
-0.4
Gain Error (%FSR)
GAIN ERROR vs SUPPLY
0.15
OFFSET VOLTAGE vs TEMPERATURE
2
5
1.5
4
3
Offset Error (mV)
Offset Error (mV)
1
0.5
0
−0.5
2
1
0
−1
−2
−1
Gain = 2
VREF = 2.5V, Internal
Code = 020h
−1.5
−2
−40
−25
−10
5
20
35
50
65
80
95
110
−3
−5
−40
TA (°C )
−25
−10
5
20
35
50
65
80
95
110
TA (°C )
Figure 28.
18
Gain = 5
VREF = 2.5V, Internal
Code = 020h
−4
Figure 29.
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
AMC7812
www.ti.com
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
TYPICAL CHARACTERISTICS: DAC (continued)
At +25°C, unless otherwise noted.
OFFSET VOLTAGE vs SUPPLY VOLTAGE
OFFSET VOLTAGE vs SUPPLY VOLTAGE
3
5
3
Offset Error (mV)
Offset Error (mV)
2
1
0
−1
TA = +25°C
Gain = 2
VREF = 2.5V, Internal
Code = 020h
−2
−3
4.5
6
7.5
9
10.5
12
13.5
15
16.5
−1
TA = +25°C
Gain = 5
VREF = 2.5V, Internal
Code = 020h
−3
−5
18
12
14
18
OUTPUT VOLTAGE vs OUTPUT CURRENT
OUTPUT VOLTAGE vs SOURCE CURRENT CAPABILITY
5
TA = +25°C
AVCC = 15V
Gain = 2
VREF = 2.5V, Internal
Code = 800h
FFFh
FF0h
FE0h
FC0h
F80h
Voltage Output (V)
4.95
2.6
2.5
2.4
2.3
2.2
4.9
4.85
4.8
TA = +25°C
AVCC = 5V
Gain = 2
VREF = 2.5V, Internal
4.75
2.1
−30
−20
−10
0
10
20
30
4.7
40
0
2
4
ILOAD (mA)
6
8
10
12
ILOAD (mA)
Figure 32.
Figure 33.
OUTPUT VOLTAGE vs SINK CURRENT CAPABILITY
DAC SUPPLY CURRENT vs DAC SUPPLY VOLTAGE
4.9
350
080h
040h
020h
010h
000h
300
250
4.7
4.5
IVCC (mA)
Voltage Output (mV)
17
Figure 31.
2.7
200
150
50
16
Figure 30.
2.8
100
15
AVCC (V)
2.9
2
−40
13
AVCC (V)
3
Voltage Output (V)
1
TA = +25°C
AVCC = 15V
Gain = 2
VREF = 2.5V, Internal
0
−12 −11 −10 −9
−8
4.3
4.1
3.9
TA = +25°C
Gain = 2
VREF = 2V, External
Code = 800h
3.7
3.5
−7
−6
−5
−4
−3
−2
−1
0
3.3
4.5
ILOAD (mA)
6
7.5
9
10.5
12
13.5
15
16.5
18
AVCC (V)
Figure 34.
Figure 35.
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
19
AMC7812
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
www.ti.com
TYPICAL CHARACTERISTICS: DAC (continued)
At +25°C, unless otherwise noted.
SUPPLY CURRENT vs DAC CODE
SUPPLY CURRENT vs TEMPERATURE
6.5
6
6.1
5.5
5.8
5
5.1
IVCC (mA)
4.7
4.4
4.5
4
4
All DAC Channels
TA = +25°C
Gain = 2
VREF = 2.5V, Internal
3.7
3.4
3
0
512
1024
1536
2048
Code
2560
3072
3584
Gain = 2
VREF = 2.5V, Internal
Code = 800h
3.5
3
−40
4096
−25
−10
5
20
Figure 36.
DAC SUPPLY CURRENT
65
80
95
110
DAC NOISE VOLTAGE vs FREQUENCY
1400
TA = +25°C
30 Units
50
TA = +25°C
Gain = 2
VREF = 2.5V, Internal
1200
1000
Noise (nV/ Hz)
40
30
20
800
600
400
6.5
6.1
6.3
5.9
5.5
5.7
5.1
5.3
4.9
4.5
4.7
4.1
0
4.3
0
3.9
200
3.5
10
3.7
Population (%)
50
Figure 37.
60
10
100
1k
10k
Frequency (Hz)
AICC (mA)
Figure 38.
100k
1M
Figure 39.
DAC NOISE 0.1Hz to 10Hz
SETTLING TIME RISING EDGE
2
20
10
5
0
−5
16
TA = +25°C
Gain = 2
VREF = 2.5V, Internal
RL= 2KΩ, CL = 250pF
DAC Out SS
DAC Out LS
CS
1.5
1
Small Signal (LSB)
TA = +25°C
Gain = 2
VREF = 2.5V, Internal
Code = 800h
15
VNOISE (µV)
35
TA (°C )
0.5
14
12
10
0
8
−0.5
6
−1
4
−1.5
2
Large Signal (V)
IVCC (mA)
5.4
−10
−15
−2
−20
0
4
8
12
16
−3
20
0
3
6
9
12
0
Time (µs)
Time (s)
Figure 40.
20
Figure 41.
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
AMC7812
www.ti.com
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
TYPICAL CHARACTERISTICS: DAC (continued)
At +25°C, unless otherwise noted.
SETTLING TIME FALLING EDGE
2
16
1.5
Small Signal (LSB)
1
0.5
14
12
10
0
8
−0.5
6
−1
4
−1.5
2
−2
−3
0
3
6
9
12
Large Signal (V)
TA = +25°C
Gain = 2
VREF = 2.5V, Internal
RL= 2KΩ, CL = 250pF
DAC Out SS
DAC Out LS
CS
0
Time (µs)
Figure 42.
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
21
AMC7812
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
www.ti.com
TYPICAL CHARACTERISTICS: ADC
At +25°C, unless otherwise noted.
LINEARITY ERROR vs CODE
1
0.8
0.8
0.6
0.6
0.4
0.4
0.2
0.2
INL (LSB)
DNL (LSB)
DIFFERENTIAL LINEARITY ERROR vs CODE
1
0
−0.2
−0.4
−0.8
−1
−0.4
TA = +25°C
0V to VREF Mode
VREF = 2.5V, Internal
Single−Ended Mode
−0.6
0
512
1024
1536
2048
Code
2560
3072
3584
0
−0.2
TA = +25°C
0V to VREF Mode
VREF = 2.5V, Internal
Single−Ended Mode
−0.6
−0.8
−1
4096
0
512
1024
Figure 43.
0.8
0.8
0.6
0.6
0.4
0.4
0.2
0.2
0
−0.2
−1
0
512
1024
1536
2048
Code
2560
3072
3584
−0.8
−1
4096
0
512
1024
0.8
0.6
0.6
0.4
0.4
0.2
0.2
INL (LSB)
DNL (LSB)
0.8
0
−0.2
TA = +25°C
0V to VREF Mode
VREF = 2.5V, Internal
Differential Mode
0
512
1024
1536
2048
Code
2560
3072
3584
4096
2560
3072
3584
4096
0
−0.2
−0.4
TA = +25°C
0V to VREF Mode
VREF = 2.5V, Internal
Differential Mode
−0.6
−0.8
−1
0
Figure 47.
22
2048
Code
LINEARITY ERROR vs CODE
1
−1
1536
Figure 46.
DIFFERENTIAL LINEARITY ERROR vs CODE
−0.8
4096
TA = +25°C
0V to (2 ⋅ VREF) Mode
VREF = 2.5V, Internal
Single−Ended Mode
−0.6
1
−0.6
3584
0
Figure 45.
−0.4
3072
−0.2
−0.4
TA = +25°C
0V to (2 ⋅ VREF) Mode
VREF = 2.5V, Internal
Single−Ended Mode
−0.8
2560
LINEARITY ERROR vs CODE
1
INL (LSB)
DNL (LSB)
DIFFERENTIAL LINEARITY ERROR vs CODE
−0.6
2048
Code
Figure 44.
1
−0.4
1536
512
1024
1536
2048
Code
2560
3072
3584
4096
Figure 48.
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
AMC7812
www.ti.com
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
TYPICAL CHARACTERISTICS: ADC (continued)
At +25°C, unless otherwise noted.
LINEARITY ERROR vs CODE
1
0.8
0.8
0.6
0.6
0.4
0.4
0.2
0.2
INL (LSB)
DNL (LSB)
DIFFERENTIAL LINEARITY ERROR vs CODE
1
0
−0.2
−0.4
−0.8
−1
−0.4
TA = +25°C
0V to (2 ⋅ VREF) Mode
VREF = 2.5V, Internal
Differential Mode
−0.6
0
512
1024
1536
2048
Code
2560
3072
3584
0
−0.2
TA = +25°C
0V to (2 ⋅ VREF) Mode
VREF = 2.5V, Internal
Differential Mode
−0.6
−0.8
−1
4096
0
1024
1536
2560
3072
3584
4096
Figure 50.
DIFFERENTIAL LINEARITY ERROR vs TEMPERATURE
DIFFERENTIAL LINEARITY ERROR vs TEMPERATURE
1
1
0.8
0.8
0.6
DNL Max
0.2
0
−0.2
−0.4
−0.6
DNL Max
0.4
DNL (LSB)
0.4
0.2
0
−0.2
−0.4
DNL Min
−1
−40 −25 −10
5
20
35
50
65
80
95
DNL Min
0V to (2 ⋅ VREF) Mode
VREF = 2.5V, Internal
Single−Ended Mode
−0.6
0V to VREF Mode
VREF = 2.5V, Internal
Single−Ended Mode
−0.8
−0.8
−1
−40 −25 −10
110 125
5
20
TA (°C )
35
50
65
80
95
110 125
TA (°C )
Figure 51.
Figure 52.
DIFFERENTIAL LINEARITY ERROR vs TEMPERATURE
DIFFERENTIAL LINEARITY ERROR vs TEMPERATURE
1
1
0.8
0.8
0.6
0.6
DNL Max
0.4
DNL (LSB)
0.4
DNL (LSB)
2048
Code
Figure 49.
0.6
DNL (LSB)
512
0.2
0
−0.2
−0.4
−0.6
0V to VREF Mode
VREF = 2.5V, Internal
Differential Mode
−0.8
−1
−40 −25 −10
5
0.2
0
−0.2
−0.4
DNL Min
20
35
50
65
80
95
110 125
DNL Max
DNL Min
0V to (2 ⋅ VREF) Mode
VREF = 2.5V, Internal
Differential Mode
−0.6
−0.8
−1
−40 −25 −10
TA (°C )
5
20
35
50
65
80
95
110 125
TA (°C )
Figure 53.
Figure 54.
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
23
AMC7812
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
www.ti.com
TYPICAL CHARACTERISTICS: ADC (continued)
At +25°C, unless otherwise noted.
LINEARITY ERROR vs TEMPERATURE
1
0.8
0.8
0.6
0.6
INL Max
0.4
0.4
0.2
0.2
INL (LSB)
INL (LSB)
LINEARITY ERROR vs TEMPERATURE
1
0
−0.2
−0.4
0V to (2 ⋅ VREF) Mode
VREF = 2.5V, Internal
Single−Ended Mode
INL Max
0
−0.2
−0.4
−0.6
INL Min
−0.8
−1
−40 −25 −10
5
−0.6
0V to VREF Mode
VREF = 2.5V, Internal
Single−Ended Mode
20
35
50
65
80
95
INL Min
−0.8
−1
−40 −25 −10
110 125
5
20
TA (°C )
LINEARITY ERROR vs TEMPERATURE
0.8
0.8
0.6
0.6
INL Max
INL (LSB)
INL (LSB)
0
−0.2
−0.4
0V to (2 ⋅ VREF) Mode
VREF = 2.5V, Internal
Differential Mode
INL Max
0
−0.2
−0.6
0V to VREF Mode
VREF = 2.5V, Internal
Differential Mode
20
35
50
65
80
95
INL Min
−0.8
−1
−40 −25 −10
110 125
5
20
TA (°C )
65
80
95
110 125
GAIN ERROR vs TEMPERATURE
3
2.5
2.5
2
2
1.5
1.5
Gain Error (LSB)
Gain Error (LSB)
GAIN ERROR vs SUPPLY
1
0.5
0
−0.5
−1
1
0.5
0
−0.5
−1
−1.5
−1.5
TA = +25°C
VREF = 2.5V, Internal
Single−Ended Mode
0V to VREF Mode
0V to (2 ⋅ VREF) Mode
3.1
3.5
3.9
4.3
4.7
5.1
5.5
−2
−2.5
0V to VREF Mode
0V to (2 ⋅ VREF) Mode
−3
−40 −25 −10
AVDD (V)
5
20
35
VREF = 2.5V, Internal
Single−Ended Mode
50
65
80
95
110 125
TA (°C )
Figure 59.
24
50
Figure 58.
3
−3
2.7
35
TA (°C )
Figure 57.
−2.5
110 125
0.2
−0.4
INL Min
−0.8
−2
95
0.4
0.2
5
80
LINEARITY ERROR vs TEMPERATURE
1
−1
−40 −25 −10
65
Figure 56.
1
−0.6
50
TA (°C )
Figure 55.
0.4
35
Figure 60.
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
AMC7812
www.ti.com
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
TYPICAL CHARACTERISTICS: ADC (continued)
At +25°C, unless otherwise noted.
OFFSET vs TEMPERATURE
CONVERSION FREQUENCY
20
5
4
0V to VREF Mode
0V to (2 ⋅ VREF) Mode
972 Units
VREF = 2.5V, Internal
Single−Ended Mode
15
2
Population (%)
Offset Error (LSB)
3
1
0
−1
−2
10
5
−3
−5
−40 −25 −10
0
5
20
35
50
65
80
95
110 125
480
482
484
486
488
490
492
494
496
498
500
502
504
506
508
510
512
514
516
518
520
−4
TA (dB)
Conversion Frequency (kHz)
Figure 61.
Figure 62.
CONVERSION FREQUENCY vs TEMPERATURE
540
530
530
Conversion Frequency (kHz)
Conversion Frequency (kHz)
CONVERSION FREQUENCY vs SUPPLY
540
520
510
500
490
480
520
510
500
490
480
470
470
TA = +25°C
460
2.7
3.1
3.5
3.9
4.3
4.7
5.1
460
−40 −25 −10
5.5
5
20
AVDD (V)
35
50
65
80
95
110 125
TA (°C )
Figure 63.
Figure 64.
SUPPLY CURRENT vs SUPPLY VOLTAGE
SUPPLY CURRENT vs TEMPERATURE
12
12
11
11
AIDD (mA)
AIDD (mA)
10
9
8
10
9
7
8
6
TA = +25°C
5
2.7
3.1
3.5
3.9
4.3
4.7
5.1
5.5
7
−40 −25 −10
AVDD (V)
5
20
35
50
65
80
95
110 125
TA (°C )
Figure 65.
Figure 66.
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
25
AMC7812
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
www.ti.com
TYPICAL CHARACTERISTICS: ADC (continued)
At +25°C, unless otherwise noted.
SUPPLY CURRENT vs CONVERSION RATE
COMBINED AVDD AND DVDD SUPPLY CURRENT
50
8
TA = +25°C
864 Units
7
40
500
AIDD (mA))
Figure 67.
26
12
400
11.5
200
300
Frequency (kHz)
11
100
10
0
0
10.5
10
9
Auto Convert Mode
Direct Mode With Nap
Direct Mode Without Nap
9.5
0
Single Channel
all DACs at code 800h
8
1
8.5
2
20
7.5
3
7
4
30
6.5
5
6
Population (%)
AIDD (mA)
6
Figure 68.
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
AMC7812
www.ti.com
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
TYPICAL CHARACTERISTICS: INTERNAL REFERENCE
At +25°C, unless otherwise noted.
OUTPUT VOLTAGE vs TEMPERATURE
OUTPUT VOLTAGE vs SUPPLY
2.505
2.501
10 Units
2.503
Voltage Output (V)
Voltage Output (V)
2.5005
2.501
2.499
2.5
2.4995
2.497
TA = +25°C
2.495
−40 −25 −10
5
20
35
50
65
80
95
2.499
2.7
110 125
3.1
3.5
3.9
TA (°C )
4.3
4.7
5.1
5.5
AVDD (V)
Figure 69.
Figure 70.
OUTPUT VOLTAGE vs OUTPUT CURRENT
OUTPUT VOLTAGE DRIFT
50
2.505
TA = -40°C to +105°C
30 Units
40
Population (%)
Output Voltage (V)
2.503
2.501
2.499
30
20
10
2.497
Figure 71.
25
20
15
10
10
8
5
6
0
4
-5
−2
0
2
ILOAD (mA)
-10
−4
-15
−6
-25
0
−8
-20
TA = +25°C
2.495
−10
Temperature Drift (ppm/°C )
Figure 72.
INTERNAL REFERENCE NOISE vs FREQUENCY
INTERNAL REFERENCE NOISE 0.1Hz to 10Hz
1000
20
TA = +25°C
Gain = 2
VREF = 2.5V, Internal
800
TA = +25°C
15
VNOISE (µV)
Noise (nV/ Hz)
10
600
400
5
0
−5
−10
200
−15
0
100
1k
10k
Frequency (Hz)
100k
1M
−20
0
4
8
12
16
20
Time (s)
Figure 73.
Figure 74.
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
27
AMC7812
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
www.ti.com
TYPICAL CHARACTERISTICS: TEMPERATURE SENSOR
At +25°C, unless otherwise noted.
LOCAL TEMPERATURE ERROR vs TEMPERATURE
REMOTE TEMPERATURE ERROR vs TEMPERATURE
2.5
Local Temperature Error (°C )
Remote Temperature Error (°C )
10 Units
QFN Package
2
1.5
1
0.5
0
−0.5
−1
−1.5
−2
−2.5
−40 −25 −10
5
20
35
50
65
80
95
1
0.5
0
−0.5
−1
−1.5
−2
5
20
35
50
65
80
95
110 125
TA (°C )
G001
Figure 75.
Figure 76.
LOCAL TEMPERATURE ERROR vs TEMPERATURE
REMOTE TEMPERATURE ERROR vs TEMPERATURE
2.5
2.5
Remote Temperature Error (°C)
16 units
TQFP Package
2
Local Temperature Error (°C)
1.5
10 Units
QFN Package
Auto Conversion Mode Disabled
−2.5
−40 −25 −10
110 125
TA (°C )
2
1.5
1
0.5
0
−0.5
−1
−1.5
−2
−2.5
−40 −25 −10
5
20
35 50
TA (°C)
65
80
95
2.0
1.5
16 units
TQFP Package
Auto Conversion Mode Disabled
1.0
0.5
0.0
−0.5
−1.0
−1.5
−2.0
−2.5
−40 −25 −10
110 125
5
20
G000
Figure 77.
35 50
TA (°C)
65
80
95
110 125
G000
Figure 78.
TYPICAL CHARACTERISTICS: DIGITAL INPUTS
At +25°C, unless otherwise noted.
SUPPLY CURRENT vs INPUT VOLTAGE
1.8
TA = +25°C
Digital Input = CS
1.6
1.4
IOVDD (mA)
1.2
1
IOVDD = 2.7V
IOVDD = 5V
0.8
0.6
0.4
0.2
0
0
0.5
1
1.5
2
2.5
3
3.5
Logic Input Voltage (V)
4
4.5
5
Figure 79.
28
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
AMC7812
www.ti.com
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
THEORY OF OPERATION
ADC OVERVIEW
The AMC7812 has two analog-to-digital converters (ADCs): a primary ADC and a secondary ADC. The primary
ADC features a 16-channel multiplexer, an on-chip track-and-hold, and a successive approximation register
(SAR) ADC based on a capacitive digital-to-analog converter (DAC). This ADC runs at 500kSPS and converts
the analog channel inputs, CH0 to CH15. The analog input range for the device can be selected as 0V to VREF or
0V to (2 · VREF). The analog input can be configured for either single-ended or differential signals. The AMC7812
has an on-chip 2.5V reference that can be disabled when an external reference is preferred. If the internal ADC
reference is to be used elsewhere in the system, the output must first be buffered. The various monitored and
uncommitted input signals are multiplexed into the ADC. The secondary ADC is a part of the temperature
sensing function that converts the analog temperature signals.
ANALOG INPUTS
The AMC7812 has 16 uncommitted analog inputs; 12 of these inputs (CH4 to CH15) are single-ended. The
inputs for CH0 to CH3 can be configured as four single-ended inputs or two fully-differential channels, depending
on the setup of the ADC Channel Registers, ADC Channel Register 0 and ADC Channel Register 1. See the
Registers section for details. Figure 80 shows the equivalent input circuit of the AMC7812. The (peak) input
current through the analog inputs depends on the sample rate, input voltage, and source impedance. The current
into the AMC7812 charges the internal capacitor array during the sample period. After this capacitance has been
fully charged, there is no further input current. The source of the analog input voltage must be able to charge the
input capacitance to a 12-bit settling level within the acquisition time. When the converter goes into hold mode,
the input impedance is greater than 1GΩ.
AVDD
50W
40W
40pF
CH0
AVDD
50W
CH3
AVDD
50W
Device in Hold Mode
CH4
AVDD
50W
CH15
50W
40W
40pF
ADC-GND
Figure 80. Equivalent Input Circuit
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
29
AMC7812
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
www.ti.com
Single-Ended Analog Input
In applications where the signal source has high impedance, it is recommended to buffer the analog input before
applying it to the ADC. The analog input range can be programmed to be either 0V to VREF or 0V to (2 · VREF). In
2 · VREF mode, the input is effectively divided by two before the conversion takes place. Note that the voltage
with respect to GND on the ADC analog input pins cannot exceed AVDD.
Fully-Differential Input
When the AMC7812 is configured as a differential input, the differential signal is defined as VDM, as shown in
Figure 81(a). It is the equivalent of the difference between the signals of V1 and V2, as shown in Figure 81(b).
The common-mode input VCOMMON is equal to (V1 + V2)/2.
When the conversion occurs, only the differential mode voltage (VDM) is converted; the common mode voltage
(VCOMMON) is rejected. This process results in a virtually noise-free signal with a maximum amplitude of –VREF to
+VREF for VREF range, or (–2 · VREF) to (+2 · VREF) for (2 · VREF) range. The results are stored in straight binary or
twos complement format.
VDM
2
VIN+
VIN+
V1
AMC7812
VCOMMON
AMC7812
VDM
2
VIN-
VINV2
(a)
(b)
Figure 81. Fully-Differential Analog Input
PRIMARY ADC OPERATION
The following sections describe the operation of the primary ADC.
ADC Trigger Signals (see AMC Configuration Register 0)
The ADC can be triggered externally by the falling edge of the external trigger CNVT, or internally by writing to
the ICONV bit in AMC Configuration Register 0. The ADC Channel Registers specify which external analog
channel is converted.
When a new trigger activates, the ADC stops any existing conversion immediately and starts a new cycle. For
example, the ADC is programmed to sample channel 0 to channel 3 repeatedly (auto-mode). During the
conversion of channel 1, an external trigger is activated. The ADC stops the conversion of channel 1 immediately
and starts the conversion of channel 0 again, instead of proceeding to convert channel 2.
Conversion Mode
Two types of ADC conversions are available: direct mode and auto mode. The CMODE (conversion mode) bit of
the AMC Configuration 0 Register specifies the conversion mode.
In direct mode, each analog channel within the specified group is converted a single time. After the last channel
is converted, the ADC goes into an idle state and waits for a new trigger.
Auto mode is a continuous operation. In auto mode, each analog channel within the specified group is converted
sequentially and repeatedly.
The flow chart of the ADC conversion sequence in Figure 82 shows the conversion process.
30
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
AMC7812
www.ti.com
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
Start
(Reset)
Wait for
ADC Trigger
First
Conversion
Yes
New
Trigger Occurred
or CMODE
Changed?
No
Stop Current
Conversion
Yes
Has
Input Channel
Register been
Rewritten?
No
Yes
Has
Input Threshold
Register been
Rewritten?
No
Yes
Is this the
Last
Conversion?
No
Yes
Direct
Mode?
Convert
Next Channel
No
Figure 82. ADC Conversion Sequence
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
31
AMC7812
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
www.ti.com
When any of following events occur, the current conversion cycle stops immediately:
• A new trigger is issued.
• The conversion mode changes.
• Either ADC channel register is rewritten.
• Any of the analog input threshold registers is rewritten.
When a new external or internal trigger activates, the ADC starts a new conversion cycle.
The internal trigger should not be issued at the same time the conversion mode is changed. If a '1' is
simultaneously written to the ICONV bit when changing the CMODE bit to '0' or '1', the current conversion stops
and immediately returns to the wait for ADC trigger state.
Double-Buffered ADC Data Registers
Single-Ended
Single-Ended/
Differential
The host can access all sixteen, double-buffered ADC Data Registers, as shown in Figure 83. The conversion
result from the analog input with channel address n (where n = 0 to 15) is stored in the ADC-n-Data Register.
When the conversion of an individual channel is completed, the data are immediately transferred into the
corresponding ADC-n temporary (TMPRY) register, the first stage of the data buffer. When the conversion of the
last channel completes, all data in the ADC-n TMPRY Registers are simultaneously transferred into the
corresponding ADC-n-Data Registers, the second stage of the data buffer. However, if a data transfer is in
progress between any ADC-n-Data Register and the AMC Shift Register, all ADC-n-Data Registers are not
updated until the data transfer is complete. The conversion result from channel address n is stored in the ADC-nData Register. For example, the result from channel 0 is stored in the ADC-0-Data Register, and the result from
channel 3 is stored in the ADC-3-Data Register.
CH0
CH1
CH2
CH3
CH4
CH5
CH6
CH7
CH8
CH9
CH10
CH11
CH12
CH13
CH14
CH15
Out-of-Limit
Alarm
ADC
ADC-0
Temporary
ADC-0
Data
ADC-7
Temporary
ADC-7
Data
ADC-15
Temporary
ADC-15
Data
To Shift
Register
Input
Range
Selection
ICONV
(Internal
Trigger)
OR
CONVERT
(External Trigger)
DAVF Bit
DAV Pin
Figure 83. Double-Buffered ADC Structure
32
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
AMC7812
www.ti.com
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
ADC Data Format
For a single ended input, the conversion result is stored in straight binary format. For a differential input, the
results are stored in twos complement format.
SCLK Clock Noise Reduction
To avoid noise caused by the bus clock, it is recommended that no bus clock activity occurs for at least the
conversion process time immediately after the ADC conversion starts.
Programmable Conversion Rate
The maximum conversion rate is 500kSPS for a single channel in auto mode, as shown in Table 1. The
conversion rate is programmable through the CONV-RATE-[1:0] bits of AMC Configuration Register 1. When
more than one channel is selected, the conversion rate is divided by the number of channels selected in ADC
Channel Register 0 and ADC Channel Register 1. In auto mode, the CONV-RATE-[1:0] bits determine the actual
conversion rate. In direct mode, the CONV-RATE-[1:0] bits limit the maximum possible conversion rate. The
actual conversion rate in direct mode is determined by the rate of the conversion trigger. Note that when a trigger
is issued, there may be a delay of up to 4µs to internally synchronize and initiate the start of the sequential
channel conversion process. In both direct and auto modes, when the CONV-RATE-[1:0] bits are set to a value
other than the maximum rate ('00'), nap mode is activated between conversions. By activating nap mode, the
AIDD supply current is reduced, as shown in Figure 67.
Table 1. ADC Conversion Rate
CONV-RATE-1
CONV-RATE-0
tACQ
(µs)
0
0
0.375
0
1
2.375
1
0
1
1
tCONV
(µs)
NAP
ENABLED
THROUGHPUT
(Single-Channel Auto Mode)
1.625
No
500kSPS (default)
1.625
Yes
250kSPS
6.375
1.625
Yes
125kSPS
14.375
1.625
Yes
62.5kSPS
Handshaking with the Host (see AMC Configuration Register 0)
The DAV pin and the DAVF (data available flag) bit in AMC Configuration Register 0 provide handshaking with
the host. Pin and bit status depend on the conversion mode (direct or auto), as shown in Figure 84 and
Figure 85. In direct mode, after ADC-n-Data Registers of all of the selected channels are updated, the DAVF bit
in AMC Configuration Register 0 is set immediately to '1', and the DAV pin is active (low) to signify that new data
are available. Reading the ADC-n-Data Register or restarting via the external CNVT pin, the ADC clears the
DAVF bit to '0' and deactivates the DAV pin (high). If an internal convert start (ICONV bit) is used to start the new
ADC conversion, in order to reset the DAV status, an ADC-n-Data Register must be read after the current
conversion finishes before a new conversion can be started.
In auto-mode, after the ADC-n-Data Registers of the selected channels are updated, a pulse of 1µs (low)
appears on the DAV pin to signify that new data are available. However, the DAVF bit is always cleared to '0' in
auto-mode.
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
33
AMC7812
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
www.ti.com
a) External Trigger, Direct Mode:
a) Internal Trigger, Direct Mode:
SS
CNVT
Set ICONV
bit to ‘1’
First
Internal
Trigger
Read Data
Set ICONV
bit to ‘1’
Second
Internal
Trigger
DATA
SDI
First
Trigger
Read Data
Second
Trigger
Third
Trigger
DATA
DAV
DAV
Second Conversion of
the Channels Specified in
the ADC Channel Register
First Conversion of
the Channels Specified in
the ADC Channel Register
Second Conversion of
the Channels Specified in
the ADC Channel Register
First Conversion of
the Channels Specified in
the ADC Channel Register
Third Conversion of
the Channels Specified in
the ADC Channel Register
b) External Trigger, Auto Mode:
b) Internal Trigger, Auto Mode:
CNVT
First
Trigger
SS
Set ICONV
bit to ‘1’
Internal
Trigger
1ms
DAV
SDI
1m s
First Conversion of
the Channels Specified in
the ADC Channel Register
DAV
First Conversion of
the Channels Specified in
the ADC Channel Register
Second Conversion
Third Conversion
Second Conversion of
the Channels Specified in
the ADC Channel Register
Third Conversion of
the Channels Specified in
the ADC Channel Register
Figure 85. ADC External Trigger
Figure 84. ADC Internal Trigger
Data Available Pin (DAV)
DAV is an output pin that indicates the completion of ADC conversions. The DAVF bit in AMC Configuration
Register 0 determines the status of the DAV pin. In direct mode, after the selected group of input channels have
been converted and the ADC has been stopped, the DAVF bit is set to '1' and the DAV pin is driven to logic low
(active). In ADC auto mode, each time the group of input channels have been sequentially converted, a 1µs
pulse (low) appears on the DAV pin.
Convert Pin (CNVT)
CNVT is the input pin for the external ADC trigger signal. ADC channel conversions begin on the falling edge of
the CNVT pulse. If a CNVT pulse occurs when the ADC is already converting, then the ADC continues
conversion of the current channel. After the completion of the current channel, the existing conversion cycle
finishes and a new conversion cycle starts. The selected channels specified in the ADC Channel Registers are
converted sequentially in order of enabled channels.
Analog Input Out-of-Range Detection (see the Analog Input Out-of-Range Alarm Section)
The analog inputs of CH0 to CH3 and the temperature inputs are implemented with out-of-range detection. When
any one of them is out of the preset range, the corresponding alarm flag in the Status Register is set. If any
inputs are out of range, the global out-of-range pin (ALARM) goes low. To avoid a false alarm, the device is
implemented with false-alarm protection. See the Alarm Operation section for more details.
Full-Scale Range of the Analog Input
The Gain bit of the ADC Gain Register determines the full-scale range of the analog input. Full-scale range is
VREF when ADGn = 0, or (2 · VREF) when ADGn = 1. If a channel pair is configured for differential operation, the
input ranges are either ±VREF or ±(2 · VREF). In (2 · VREF) mode, the input is effectively divided by two before the
conversion takes place. Each input must not exceed the supply value of AVDD + 0.2V or AGND - 0.2V. When the
REF-OUT pin is connected to the REF-ADC pin, the internal reference is used as the ADC reference. When an
external reference voltage is applied to the REF-ADC pin, the external reference is used as the ADC reference.
34
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
AMC7812
www.ti.com
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
SECONDARY ADC/TEMPERATURE SENSOR OPERATION
The AMC7812 contains one local and two remote temperature sensors. The temperature sensors continuously
monitor the three temperature inputs, and new readings are automatically available every cycle. The on-chip
integrated temperature sensor (shown in Figure 86) is used to measure the device temperature, and two remote
diode sensor inputs are used to measure the two external temperatures. All analog signals are converted by the
secondary ADC that runs in the background at a lower speed. The measurement relies on the characteristics of
a semiconductor junction operation at a fixed current level. The forward voltage of the diode (VBE) depends on
the current passing through it and the ambient temperature. The change in VBE when the diode operates at two
different currents (a low current of ILOW and a high current of IHIGH, is shown in Equation 1:
IHIGH
hkT
VBE_HIGH - VBE_LOW =
ln
q
ILOW
( )
Where:
k is Boltzmann's constant.
q is the charge of the carrier.
T is the absolute temperature in Kelvins (K).
η is the ideality of the transistor as sensor.
(1)
IHIGH
ILOW
SW2
SW1
Mux
LPF and Signal
Conditioning
Local
Temperature
Registers
Second ADC
and Signal
Processing
Diode
Temperature
Sensor
Figure 86. Integrated Local Temperature Sensor
The remote sensing transistor can be a discrete small-signal type transistor or substrate transistor built within the
microprocessor. This architecture is shown in Figure 87. An internal voltage source biases the D– terminal above
ground to prevent the ground noise from interfering with the measurement. An external capacitor (up to 330pF)
may be placed between D+ and D– to further reduce noise interference.
ILOW
SW1
Remote
Temperature
Registers
IHIGH
SW2
D+
Mux
D-
LPF and Signal
Conditioning
Second ADC
and Signal
Processing
VBIAS
Figure 87. Remote Temperature Sensor
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
35
AMC7812
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
www.ti.com
The AMC7812 has three temperature sensors: two remote (D1 and D2) and one on-chip (LT). If any sensor is
not used, it can be disabled by clearing the corresponding enable bit (bits D2EN, D1EN, and LTEN of the Temp
Configuration Register). When disabled, the sensors are not converted. The AMC7812 continuously monitors the
selected temperature sensors in the background, leaving the user free to perform conversions on the other
channels. When one monitor cycle finishes, a signal passes to the control logic to automatically initiate a new
conversion.
The analog sensing signal is preprocessed by a low-pass filter and signal conditioning circuitry, and then
digitized by the ADC. The resulting digital signal is further processed by the digital filter and processing unit. The
final result is stored in the LT-Temperature-Data Register, the D1-Temperature-Data Register, and the D2Temperature-Data Register, respectively. The format of the final result is in twos complement, as shown in
Table 2. Note that the device measures the temperature from –40°C to +150°C.
Table 2. Temperature Data Format
36
TEMPERATURE (°C)
DIGITAL CODE
+255.875
011111111111
+150
010010110000
+100
001100100000
+50
000110010000
+25
000011001000
+1
000000001000
0
000000000000
–1
111111111000
–25
111100111000
–50
111001110000
–100
110011100000
–150
101101010000
–256
100000000000
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
AMC7812
www.ti.com
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
Remote Sensing Diode
Errors in remote temperature sensor readings are typically the consequence of the ideality factor and current
excitation used by the AMC7812 versus the manufacturer-specified operating current for a given transistor. Some
manufacturers specify a low-level (ILOW) and high-level (IHIGH) current for the temperature-sensing substrate
transistors. The AMC7812 uses 6μA for ILOW and 120μA for IHIGH. The AMC7812 is designed to work with
discrete transistors, such as the 2N3904 and 2N3906. If an alternative transistor is used, the AMC7812 operates
as specified, as long as the following conditions are met:
1. Base-emitter voltage > 0.25V at 6μA, at the highest sensed temperature.
2. Base-emitter voltage < 0.95V at 120μA, at the lowest sensed temperature.
3. Base resistance < 100Ω.
4. Tight control of VBE characteristics indicated by small variations in hFE (that is, 50 to 150).
Ideality Factor
The ideality factor (η) is a measured characteristic of a remote temperature sensor diode as compared to an
ideal diode. The AMC7812 allows for different η-factor values, according to Table 3. The AMC7812 is trimmed for
a power-on reset (POR) value of η = 1.008. If η is different, the η-Factor Correction Register can be used. The
value (NADJUST) written in this register must be in twos complement format, as shown in Table 3. This value is
used to adjust the effective η-factor according to Equation 2 and Equation 3.
Table 3. η-Factor Range (Single Byte)
NADJUST
HEX
DECIMAL
ηEFF
0111 1111
7F
127
1.747977
0000 1010
0A
10
1.042759
0000 1000
08
8
1.035616
0000 0110
06
6
1.028571
0000 0100
04
4
1.021622
0000 0010
02
2
1.014765
0000 0001
01
1
1.011371
0000 0000
00
0
1.008
1111 1111
FF
–1
1.004651
1111 1110
FE
–2
1.001325
1111 1100
FC
–4
0.994737
1111 1010
FA
–6
0.988235
1111 1000
F8
–8
0.981818
1111 0110
F6
–10
0.975484
1000 0000
80
–128
0.706542
BINARY
heff =
1.008 ´ 300
300 - NADJUST
NADJUST = 300 -
(2)
300 ´ 1.008
heff
Where:
ηEFF is the actual ideality of the transistor being used
NADJUST is the corrected ideality being used in the calculation
(3)
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
37
AMC7812
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
www.ti.com
Filtering
Figure 88 shows the connection of recommended (a) NPN or (b) PNP transistors. Remote junction temperature
sensors are usually implemented in a noisy environment. Noise is most often created by fast digital signals, and
it can corrupt measurements. The AMC7812 has a built-in 65kHz filter on the inputs of D+ and D-, to minimize
the effects of noise. However, a bypass capacitor placed differentially across the inputs of the remote
temperature sensor can make the application more robust against unwanted coupled signals. If filtering is
required, the capacitance between D+ and D– should be limited to 330pF or less for optimum measurement
performance. This capacitance includes any cable capacitance between the remote temperature sensor and the
AMC7812.
2N3906
2N3904
D+
D+
AMC7812
AMC7812
D-
D-
(a) NPN
(b) PNP
Figure 88. Remote Temperature Sensor Using Transistor
Series Resistance Cancellation
Parasitic resistance (seen in series with the remote diode) to the D+ and D– inputs to the AMC7812 is caused by
a variety of factors, including printed circuit board (PCB) trace resistance and trace length. This series resistance
appears as a temperature offset in the remote sensor temperature measurement, and causes more than 0.45°C
error per ohm. The AMC7812 implements a technology to automatically cancel out the effect of this series
resistance, giving a more accurate result without the need for user characterization of this resistance. With this
technology, the AMC7812 is able to reduce the effects of series resistance to typically less than 0.0075°C per
ohm. The resistance cancellation is disabled when the RC bit in Temperature Configuration Register is cleared
('0').
Reading Temperature Data
The temperature is always read as 12-bit data. When the conversion finishes, the temperature is sent to the
corresponding Temp-Data Register. However, if a data transfer is in progress between the Temp-Data Register
and the AMC Shift Register, the Temp-Data Register is frozen until the data transfer is complete.
Conversion Time
The conversion time depends on the type of sensor and configuration, as shown in Table 4.
Table 4. Conversion Times
MONITORING
CYCLE TIME (ms)
PROGRAMMABLE
DELAY RANGE (s)
Local sensor is active, remote sensors are disabled or in power-down
15
0.48 to 3.84
One remote sensor is active and RC = '0', local sensor and one remote sensor are disabled
or in power-down
44
1.40 to 11.2
One remote sensor is active and RC = '1', local sensor and one remote sensor are disabled
or in power-down
93
2.97 to 23.8
One remote sensor and local sensor are active and RC = '0', one remote sensor is disabled
or in power-down
59
1.89 to 15.1
One remote sensor and local sensor are active and RC = '1', one remote sensor is disabled
or in power-down
108
3.45 to 27.65
Two remote sensors are active and RC = '0', local sensor is disabled or in power-down
88
2.81 to 22.5
Two remote sensors are active and RC = '1', local sensor is disabled or in power-down
186
5.95 to 47.6
All sensors are active and RC = '0'
103
3.92 to 26.38
All sensors are active and RC = '1'
201
6.43 to 51.45
TEMPERATURE SENSOR
38
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
AMC7812
www.ti.com
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
REFERENCE OPERATION
The following sections describe the operation of the internal and external references.
Internal Reference
The AMC7812 includes a 2.5V internal reference. The internal reference is externally available at the REF-OUT
pin. A 100pF to 10nF capacitor is recommended between the reference output and GND for noise filtering. The
internal reference is a bipolar transistor-based, precision bandgap voltage reference. The output current is limited
by design to approximately 100mA.
The internal reference drives all temperature sensors. When connecting the REF-OUT pin to the REF-DAC pin,
the internal reference works as the DAC reference.
The ADC-REF-IN/CMP pin has a dual function. When an external reference is connected to this pin, the external
reference is used as the ADC reference. When a compensation capacitor ( 4.7µF, typical) is connected between
this pin and AGND, the internal reference is used as the ADC reference. When using an external reference to
drive the ADC, the ADC-REF-INT bit in AMC Configuration Register 0 must be cleared ('0') to turn off the ADC
reference buffer. When using the internal reference to drive the ADC, the ADC-REF-INT bit in AMC Configuration
Register 0 must be set to '1' to turn on the ADC reference buffer.
External Reference
Figure 89 shows how the external reference is used as the DAC reference when applied on the DAC-REF pin,
and as the ADC reference when applied on the ADC-REF pin. Figure 90 shows the use of the internal reference.
CH0
CH1
CH0
CH1
ADC
ADC
CH14
CH15
Ext.
Ref.
CH14
CH15
ADC-REF-IN/CMP
ADC-REF-IN/CMP
Control Logic: Bit
ADC-REF-INT = ‘0’
REF-OUT
Reference
(2.5V)
Control Logic:
Bit PREF = ‘0’
DAC-0
REF-DAC
REF-OUT
Reference
(2.5V)
Control Logic:
Bit PREF = ‘1’
Ext.
Ref.
DAC0-OUT
Figure 89. Use of the External Reference
Control Logic: Bit
ADC-REF-INT = ‘1’
C > 470nF
(Minimize
Inductance
to Pin)
DAC-0
REF-DAC
DAC0-OUT
Figure 90. Use of the Internal Reference
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
39
AMC7812
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
www.ti.com
DAC OPERATION
The AMC7812 contains 12 DACs that provide digital control with 12 bits of resolution using an internal or
external reference. The DAC core is a 12-bit string DAC and output buffer. The DAC drives the output buffer to
provide an output voltage. Refer to the DAC Configuration Register for details. Figure 91 shows a function block
diagram of the DAC architecture. The DAC Latch stores the code that determines the output voltage from the
DAC string. The code is transferred from the DAC-n-Data Register to the DAC Latch when the internal DACLoad signal is generated.
DAC
Data
Register
DAC
Latch
12-Bit
Resistor
String
VOUT
DAC Load(1)
Gain Logic
Gain Bits
(1)
Gain
Internal DAC load is generated by writing '1' to ILDAC bit in synchronous mode. In asynchronous mode, the DAC
latch is transparent.
Figure 91. DAC Block Diagram
Resistor String
The resistor string structure is shown in Figure 92. It consists of a string of resistors, each of value R. The code
loaded to the DAC Latch determines at which node on the string the voltage is tapped off to be fed into the
output amplifier. The voltage is tapped off by closing one of the switches connecting the string to the amplifier.
This architecture is inherently monotonic, voltage out, and low glitch. It is also linear because all the resistors are
of equal value.
R
R
R
To Output
Amplifier
R
R
Figure 92. Resistor String
40
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
AMC7812
www.ti.com
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
DAC Output
The output range is programmable from 0 to (2 · VREF) or from 0 to (5 · VREF), depending on the gain bits in the
DAC Gain Register. The maximum output is AVCC. The output buffer amplifier is capable of generating rail-to-rail
voltages on its output, giving an output range of 0V to AVCC. The source and sink capabilities of the output
amplifier can be seen in the Typical Characteristics. The slew rate is 1.5V/μs with a typical ¼ to ¾ scale settling
time of 3μs with the output unloaded.
Double-Buffered DAC Data Registers
There are 12 double-buffered DAC data registers. Each DAC has an internal latch preceded by a DAC Data
Register. Data are initially written to an individual DAC-n-Data Register and then transferred to the corresponding
DAC-n Latch. When the DAC-n Latch is updated, the output of DAC-n changes to the newly set value. When the
host reads the register memory map location labeled DAC-n Data, the value held in the DAC-n Latch is returned
(not the value held in the input DAC-n-Data Register).
Full-Scale Output Range
The full-scale output range of each DAC is set by the product of the value of the reference voltage times the gain
of the DAC output buffer (VREF · Gain). The gain bits of the DAC Gain Register set the output range of the
individual DAC-n. The full-scale output range of each DAC is limited by the analog power supply. The maximum
output from the DAC must not be greater than AVCC, and the minimum output must not be less than AGND.
DAC Output After Power-On Reset
After power on, the DAC output buffer is in power-down mode. The output buffer is in a Hi-Z state and the DACOut output pin connects to the analog ground through an internal 10kΩ resistor. After power on or hardware
reset, all DAC-n-Data Registers, all DAC-n Latches, and the DAC output are set to default values (000h).
Load DAC Latch
See Figure 91 for the structure of the DAC register and DAC latch. The contents of the DAC-n Latch determine
the output level of the DAC-n pin. After writing to the DAC-n-Data Register, the DAC Latch can be loaded in the
following ways:
• In asynchronous mode (SLDAC-n bit = '0'), the data are loaded into the DAC-n Latch immediately after the
write operation.
• In synchronous mode (SLDAC-n bit = '1'), the DAC latch updates when the synchronous DAC loading signal
occurs. Setting the ILDAC bit in AMC Configuration Register 0 generates the loading signal.
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
41
AMC7812
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
www.ti.com
Synchronous Load, Asynchronous Load, and Output Updating
The SLDA-n (synchronous load) bit of the DAC Configuration Register determines the DAC updating mode, as
shown in Table 5. When SLDA-n is cleared to '0', asynchronous mode is active, the DAC Latch updates
immediately after writing to the DAC-n-Data Register, and the output of DAC-n changes accordingly.
Table 5. DAC-n Output Update Summary for Manual Mode Update
SLDA-n BIT
WRITING TO ILDAC BIT
0
Don't care
1
1
OPERATION
Update DAC-n individually. The DAC-n Latch and DAC-n output are immediately
updated after writing to the DAC-n-Data Register.
Simultaneously update all DACs by internal trigger. Writing '1' to the ILDAC bit
generates an internal load DAC trigger signal that updates the DAC-n Latches and
DAC-n outputs with the contents of the corresponding DAC-n-Data Register.
When the SLDA-n bit is set to '1', synchronous mode is selected. The value of the DAC-n-Data Register is
transferred to the DAC-n Latch only after an active DAC synchronous loading signal (ILDAC) occurs, which
immediately updates the DAC-n output. Under synchronous loading operation, writing data into a DAC-n-Data
Register changes only the value in that register, but not the content of DAC-n Latch nor the output of DAC-n,
until the synchronous load signal occurs.
The DAC synchronous load is triggered by writing '1' to the ILDAC bit in AMC Configuration Register 0. When
this DAC synchronous load signal occurs, all DACs with the SLDA-n bit set to '1' are simultaneously updated with
the value of the corresponding DAC-n-Data Register. By setting the SLDA-n bit properly, several DACs can be
updated at the same time. For example, to update DAC0 and DAC1 synchronously, set bits SLDA-0 and SLDA-1
to '1' first, and then write the proper values into the DAC-0 and DAC-1-Data Registers, respectively. After this
presetting, set the ILDAC bit = '1' to simultaneously load DAC0 and DAC1. The outputs of DAC0 and DAC1
change at the same time.
The AMC7812 updates the DAC Latch only if it has been accessed since the last time ILDAC was issued,
thereby eliminating any unnecessary glitch. Any DAC channels that have not been accessed are not reloaded
again. When the DAC Latch is updated, the corresponding output changes to the new level immediately.
NOTE
When DACs are cleared by an external DAC-CLR-n or by the internal CLR bit, the DAC
Latch is loaded with the predefined value of the DAC-n-CLR-Setting Register and the
output is set to the corresponding level immediately, regardless of the SLDA-n bit value.
However, the DAC Data Register does not change.
42
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
AMC7812
www.ti.com
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
Clear DACs
DAC-n can be cleared using hardware or software as shown in Figure 93. When DAC-n goes to a clear state, it
is immediately loaded with predefined code in the DAC-n-CLR-Setting Register, and the output is set to the
corresponding level to shut down the external LDMOS device. However, the DAC-DATA-n Register does not
change. When the DAC goes back to normal operation, DAC-n is immediately loaded with the previous data from
the DAC-DATA-n Register and the output of DAC-n-Out is set back to the previous level to restore LDMOS to the
status before shutdown, regardless of the SLDAC-n bit status.
DAC
Data Register
DAC
Latch
0
DAC
1
DAC
CLR-Setting
Register
DAC-CLR-n Pin
CLR-n Bit in HW-DAC-CLR-n Register
CLR-n Bit in SW-DAC-CLR-n Register
ACLR-n Bit
Alarm Source
Figure 93. Clearing DAC-n
The AMC7812 is implemented with two external control lines, the DAC-CLR-0 and DAC-CLR-1 pins, to clear the
DACs. When either pin goes low, the corresponding user-selected DACs are in a cleared state. The HW_DACCLR-0 Register determines which DAC is cleared when the DAC-CLR-0 pin is low. The register contains 12 clear
bits (CLR-n), one per DAC. If the CLR-n bit = '1', DAC-n is in a cleared state when the DAC-CLR-0 pin is low.
However, if the CLR-n bit = '0', DAC-n does not change when the pin is low. Likewise, the HW-DAC-CLR-1
Register determines which DAC is cleared when the DAC-CLR-1 pin is low.
Writing directly to the SW_DAC_CLR Register puts the selected DACs in a cleared state. DACs can also be
forced into a clear state by alarm events. The AUTO-DAC-CLR-SOURCE Register specifies which alarm events
force the DACs into a clear state, and the AUTO-DAC-CLR-EN Register defines which DACs are forced into a
clear state. Refer to the AUTO-DAC-CLR-SOURCE and AUTO-DAC-CLR-EN Registers for further details.
DAC Output Thermal Protection
A significant amount of power can be dissipated in the DAC outputs. The AMC7812 is implemented with a
thermal protection circuit that sets the THERM-ALR bit in the Status Register if the die temperature exceeds
+150°C. The THERM-ALR bit can be used in combination with THERM-ALR-CLR (bit 2 in the AUTO-DAC-CLRSOURCE Register) and ACLR-n (bits[14:3] in the AUTO-DAC-CLR-EN Register) to set the DAC output to a
predefined code when this condition occurs. Note that this feature is disabled when the local temperature sensor
powers down.
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
43
AMC7812
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
www.ti.com
Alarm Operation
The AMC7812 continuously monitors all analog inputs and temperatures in normal operation. When any input is
out of the specified range, an alarm triggers. When an alarm state occurs, the corresponding individual alarm bit
in the Status Register is set ('1'). Global alarm bit GALR in AMC Configuration Register 0 is the OR of individual
alarms, see Figure 94. When the ALARM-LATCH-DIS bit in the Alarm Control Register is cleared ('0'), the alarm
is latched. The global alarm bit (GALR) maintains '1' until the corresponding error condition[s] subside and the
alarm status is read. The alarm bits are referred to as being latched because they remain set until read by
software. This design ensures that out-of-limit events cannot be missed if the software is polling the device
periodically. All bits are cleared when reading the Status Register, and all bits are reasserted if the out-of limit
condition still exists on the next monitoring cycle, unless otherwise noted.
CH0-ALR
Alarm
Status
Bits
GALR Bit
THERM-ALR
Figure 94. Global Alarm Bit
When the ALARM-LATCH-DIS bit in the Alarm Control Register is set ('1'), the alarm bit is not latched. The alarm
bit in the Status Register goes to '0' when the error condition subsides, regardless of whether the bit is read or
not. When GALR = '1', the ALARM pin goes low. When the GALR bit = '0', the ALARM is high (inactive).
44
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
AMC7812
www.ti.com
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
Analog Input Out-of-Range Alarm
The AMC7812 provides out-of-range detection for four individual analog inputs (CH0, CH1, CH2, and CH3) as
shown in Figure 95. When the measurement is out-of-range, the corresponding alarm bit in the Status Register is
set to '1' to flag the out-of-range condition. The value in the High-Threshold Register defines the upper bound
threshold of the nth analog input, while the value in Low-Threshold defines the lower bound. These two bounds
specify a window for the out-of-range detection.
High-Threshold-n
Register
(upper bound)
CHn-ALR Bit
nth Analog Input
(n = 0 to 3)
Low-Threshold-n
Register
(lower bound)
Figure 95. CHn Out-of-Range Alarm
The AMC7812 also has high-limit or low-limit detection for the temperature sensors (D1, D2, and LT), as shown
in Figure 96. To implement single, upper-bound threshold detection for analog input CHn, the host processor can
set the upper-bound threshold to the desired value and the lower-bound threshold to the default value. For lowerbound threshold detection, the host processor can set the lower-bound threshold to the desired value and the
upper-bound threshold to the default value. Note that the value of the High-Threshold Register must not be less
than the value of the Low-Threshold Register; otherwise, ALR-n is always set to '1' and the alarm indicator is
always active. Each temperature sensor has two alarm bits: High-ALR (high-limit alarm) and Low-ALR (low-limit
alarm).
High-Threshold
(upper bound)
High-ALR Bit
Temperature Data
(D1, D2, LT)
Low-ALR Bit
Low-Threshold
(lower bound)
Figure 96. Temperature Out-of-Range Alarm
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
45
AMC7812
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
www.ti.com
ALARM pin
The ALARM pin is a global alarm indicator. ALARM is an open-drain pin, as Figure 97 illustrates; an external
pull-up resistor is required. When the pin is activated, it goes low. When the pin is inactive, it is in Hi-Z status.
The ALARM pin works as an interrupt to the host so that it may query the Status Register to determine the alarm
source. Any alarm event (including analog inputs, temperatures, diode status, and device thermal condition)
activates the pin if the alarm is not masked (the corresponding EALR bit in the Alarm Control Register = '1').
When the alarm pin is masked (EN-ALARM bit = '0'), the occurrence of the event sets the corresponding status
bit in Status Register to '1', but does not activate the ALARM pin.
CH0-ALR Bit
ALARM
EALR-CH0 Bit
G1
D2-FAIL-ALR Bit
EALR-D2-FAIL Bit
THERM-ALR Bit
EN-ALARM Bit
AMC7812
Figure 97. ALARM Pin
When the ALARM-LATCH-DIS bit in the Alarm Control Register is cleared ('0'), the alarm is latched. Reading the
Status Register clears the alarm status bit. Whenever an alarm status bit is set, indicating an alarm condition, it
remains set until the event that caused it is resolved and the Status Register is read. The alarm bit can only be
cleared by reading the Status Register after the event is resolved, or by hardware reset, software reset, or
power-on reset (POR). All bits are cleared when reading the Status Register, and all bits are reasserted if the
out-of limit condition still exists after the next conversion cycle, unless otherwise noted. When the ALARMLATCH-DIS bit in the Alarm Control Register is set ('1'), the ALARM pin is not latched. The alarm bit clears to '0'
when the error condition subsides, regardless of whether the bit is read or not.
46
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
AMC7812
www.ti.com
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
Hysteresis
The AMC7812 continuously monitors the analog input channels and temperatures. If any of the alarms are out of
range and the alarm is enabled, its alarm bit is set ('1'). However, the alarm condition is cleared only when the
conversion result returns to a value of at least hys below the value of High Threshold Register, or hys above the
value of Low Threshold Register. The Hysteresis Registers store the value for each analog input (CH0, CH1,
CH2, and CH3) and temperature (D1, D2, and LT). hys is the value of hysteresis that is programmable: 0 LSB to
127 LSB for analog input, and 0°C to +31°C for temperatures. For the THERM-ALR bit, the hysteresis is fixed at
8°C. The hysteresis behavior is shown in Figure 98.
High Threshold
Hysteresis
Input
Hysteresis
Low Threshold
Over High Alarm
Below Low Alarm
Figure 98. Hysteresis
False Alarm Protection
As noted previously, the AMC7812 continuously monitors all analog inputs and temperatures in normal operation.
When any input is out of the specified range in N consecutive conversions, the corresponding alarm bit is set
('1'). If the input returns to the normal range before N consecutive times, the alarm bit remains clear ('0'). This
design avoids false alarms.
The number N is programmable by the CH-FALR-CT-[2:0] bits in AMC Configuration Register 1 for analog input
CH-n as shown in Table 6, or by the TEMP-FALR-CT-[1:0] bits for temperature monitors as shown in Table 7.
Table 6. Consecutive Sample Number for False Alarm Protection for CH-n
CH-FALR-CT-2
CH-FALR-CT-1
CH-FALR-CT-0
N CONSECUTIVE SAMPLES
BEFORE ALARM IS SET
0
0
0
1
0
0
1
4
0
1
0
8
0
1
1
16 (default)
1
0
0
32
1
0
1
64
1
1
0
128
1
1
1
256
Table 7. Consecutive Sample Number for False Alarm Protection for Temperature Channels
TEMP-FALR-CT-1
TEMP-FALR-CT-0
N CONSECUTIVE SAMPLES BEFORE ALARM IS SET
0
0
1
0
1
2
1
0
4 (default)
1
1
8
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
47
AMC7812
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
www.ti.com
GENERAL-PURPOSE INPUT/OUTPUT PINS (GPIO-0 to GPIO-7)
The AMC7812 has eight GPIO pins. The GPIO-0, -1, -2 and -3 pins are dedicated to general, bidirectional, digital
I/O signals. GPIO-4, GPIO-5, GPIO-6 and GPIO-7 are dual-function pins and can be programmed as either
bidirectional digital I/O pins or remote temperature sensors D1 and D2. When D1 or D2 is disabled, the pins work
as a GPIO. These pins can receive an input or produce an output. When the GPIO-n pin acts as an output, it has
an open-drain, and the status is determined by the corresponding GPIO-n bit of the GPIO Register. The output
state is high impedance when the GPIO-n bit is set to '1', and is logic low when the GPIO-n bit is cleared ('0').
Note that a 10kΩ pullup resistor is required when using the GPIO-n pin as an output, see Figure 99. The dual
function GPIO-4, -5, -6 and -7 pins should not be tied to a pullup voltage that exceeds the AVDD supply. The
dedicated GPIO-0, -1, -2 and -3 pins are only restricted by the absolute maximum voltage. To use the GPIO-n
pin as an input, the corresponding GPIO-n bits in the GPIO Register must be set to '1'. When the GPIO-n pin
acts as input, the digital value on the pin is acquired by reading the corresponding GPIO-n bit. After a power-on
reset or any forced hardware or software reset, all GPIO-n bits are set to '1', and the GPIO-n pin goes to a highimpedance state.
V+
GPIO-n
GPIO-n Bit
(when writing)
ENABLE
GPIO-n Bit
(when reading)
Figure 99. GPIO Pins
HARDWARE RESET
Pulling the RESET pin low performs a hardware reset. When the RESET pin is low, the device enters a reset
state, all registers are set to the default values (including the Power-Down Register); therefore, all function blocks
(except the internal temperature sensor) are in power-down mode. On the rising edge of RESET, the device
returns to the normal operating mode. After returning, all registers remain set to the default value until a new
value is written. Note that after reset, it is important to properly write to the power-down register in order to
activate the device. Hardware reset should only be issued when DVDD has reached the minimum specification of
2.7V or above.
SOFTWARE RESET
Software reset returns all register settings to their default and can be performed by writing to the Software Reset
Register. In the case of I2C communication, any value written to this register results in a reset condition. In the
case of SPI communications, only writing the specific value of 6600h to this register resets the device. See the
Registers section for details. During reset, all communication is blocked. After issuing the reset, the user should
wait at least 30µs before attempting to resume communication.
POWER-ON RESET (POR)
When powered on, the internal POR circuit invokes a power-on reset, which performs the equivalent function of
the RESET pin. To ensure a POR, DVDD must start from a level below 750mV.
48
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
AMC7812
www.ti.com
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
POWER SUPPLY SEQUENCE
The preferred (not required) order for applying power is IOVDD, DVDD/AVDD and then AVCC. All registers
initialize to the default values after these supplies have been established. Communication with the AMC7812 will
be valid after a 250µS maximum power-on reset delay. The default state of all analog blocks is off as determined
by the power-down register (6Bh). Before writing to this register, a hardware reset should be issued to ensure
specified operation of the AMC7812. Communication to the AMC7812 will be valid after a maximum 250µS reset
delay from the rising edge of RESET.
If DVDD falls below 2.7V, the minimum supply value of DVDD, either a hardware or power-on reset should be
issued before proper operation can be resumed.
To avoid activating the ESD protection diodes of the AMC7812, GPIO-4, GPIO-5, GPIO-6 and GPIO-7 inputs
should not be applied before the AVDD is established. Also, if using the external reference configuration of the
ADC, ADC-REF-IN/CMP should not be applied before AVDD.
PRIMARY COMMUNICATION INTERFACE
The AMC7812 communicates with the system controller through the primary communication interface, which can
be configured as either an I2C-compatible two-wire bus or an SPI bus. When the SPI/I2C pin is tied to ground,
the I2C interface is enabled, and the SPI is disabled. When the SPI/I2C pin is tied to IOVDD, the I2C interface is
disabled, and SPI is enabled.
I2C-Compatible Interface
This device uses a two-wire serial interface compatible with the I2C-bus specification, version 2.1. The bus
consists of a data line (SDA) and a clock line (SCL) with pull-up structures. When the bus is idle, both SDA and
SCL lines are pulled high. All the I2C-compatible devices connect to the I2C bus through open-drain I/O pins SDA
and SCL. A master device, usually a micro controller or a digital signal processor, controls the bus. The master is
responsible for generating the SCL signal and device addresses. The master also generates specific conditions
that indicate the start and stop of data transfers. A slave device receives and/or transmits data on the bus under
control of the master device. The AMC7812 works as a slave and supports the following data transfer modes, as
defined in the I2C-bus specification: standard mode (100kbps), fast mode (400kbps), and high-speed mode
(3.4Mbps). The data transfer protocol for standard and fast modes is exactly the same; therefore, they are
referred to as F/S mode in this document. The protocol for high-speed mode is different from the F/S mode, and
is referred to as Hs mode. The AMC7812 supports 7-bit addressing. However 10-bit addressing and general call
addressing are not supported. The slave address of the AMC7812 is determined by the status of pins A0, A1,
and A2, as shown in Table 8.
Table 8. Slave Addresses
A0
A1
A2
SLAVE ADDRESS
GND
GND
GND
GND
1100001
GND
IOVDD
1100010
GND
IOVDD
GND
1100100
GND
IOVDD
IOVDD
1100101
IOVDD
GND
GND
0101100
IOVDD
GND
IOVDD
0101101
IOVDD
IOVDD
GND
0101110
IOVDD
IOVDD
IOVDD
0101111
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
49
AMC7812
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
www.ti.com
F/S-Mode Protocol
• The master initiates the data transfer by generating a start condition. The start condition is when a high-to-low
transition occurs on the SDA line while SCL is high, as shown in Figure 2. All I2C-compatible devices must
recognize a start condition.
• The master then generates the SCL pulses, and transmits the 7-bit address and the read/write direction bit
R/W on the SDA line. During all transmissions, the master ensures that data are valid. A valid data condition
requires the SDA line to be stable during the entire high period of the clock pulse (see Figure 2). All devices
recognize the address sent by the master and compare it to their internal fixed addresses. Only the slave
device with a matching address generates an acknowledge (see Figure 2) by pulling the SDA line low during
the entire high period of the ninth SCL cycle. Upon detecting this acknowledge, the master recognizes that
communication link with a slave has been established.
• The master generates further SCL cycles to either transmit data to the slave (R/W bit = '1') or receive data
from the slave (R/W bit = '0'). In either case, the receiver must acknowledge the data sent by the transmitter.
Therefore, an acknowledge signal can either be generated by the master or by the slave, depending on which
one is the receiver. The 9-bit valid data sequences consisting of 8-bit data and 1-bit acknowledge can
continue as long as necessary.
• To signal the end of the data transfer, the master generates a stop condition by pulling the SDA line from lowto-high while the SCL line is high (see Figure 2). This action releases the bus and stops the communication
link with the addressed slave. All I2C-compatible devices must recognize the stop condition. Upon the receipt
of a stop condition, all devices recognize that the bus is released and wait for a start condition followed by a
matching address.
Hs-Mode Protocol
• When the bus is idle, both SDA and SCL lines are pulled high by the pull-up devices.
• The master generates a start condition followed by a valid serial byte containing Hs master code 00001xxx.
This transmission is made in F/S mode at no more than 400 kbps. No device is allowed to acknowledge the
Hs master code, but all devices must recognize it and switch their internal setting to support 3.4 Mbps
operation.
• The master then generates a repeated start condition (a repeated start condition has the same timing as the
start condition). After this repeated start condition, the protocol is the same as for F/S mode, except that
transmission speeds up to 3.4 Mbps are allowed. A stop condition ends Hs mode and switches all the internal
settings of the slave devices to support F/S mode. Note that instead of using a stop condition, repeated start
conditions should be used to secure the bus in Hs mode.
Address Pointer
The Address Pointer Register of AMC7812 is an 8-bit register. Each register has an address and when it is
accessed, the address pointer points to it. All registers in the AMC7812 are 16-bit, consisting of a high byte
(D15:D8) and a low byte (D7:D0). The high byte is always accessed first, and the low byte accessed second.
When the register is accessed, the entire register is frozen until the operation on the low byte is complete. During
write operation, the new content does not take effect until the low byte is written. In read operation, the whole
register value is frozen until the low byte is read.
The address pointer does not change after the current register is accessed. To change the pointer, the master
issues a slave address byte with the R/W bit low, followed by the Pointer Register byte; no additional data are
required.
AMC7812 Communication Protocol for I2C
The AMC7812 uses the following I2C protocols.
Writing a Single Word of Data to a 16-Bit Register (Figure 100)
1. The master device asserts a start condition.
2. The master then sends the 7-bit AMC7812 slave address followed by a zero for the direction bit, indicating a
write operation.
3. The AMC7812 asserts an acknowledge signal on SDA.
4. The master sends a register address.
5. The AMC7812 asserts an acknowledge signal on SDA.
50
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
AMC7812
www.ti.com
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
6. The master sends a data byte of the high byte of the register (D15:D8).
7. The AMC7812 asserts an acknowledge signal on SDA.
8. The master sends a data byte of the low byte of the register (D7:D0).
9. The AMC7812 asserts an acknowledge signal on SDA.
10. The master asserts a stop condition to end the transaction.
S
AMC7812
Slave Address
From Master to Slave
From Slave to Master
0
A
Register Pointer
(Register Address)
A
High Byte to
AMC7812 Register
A
Low Byte to
AMC7812 Register
A
P
A = Acknowledge
N = Not Acknowledge
S = START Condition
P = Stop Condition
Sr = Repeated START Condition
Figure 100. Write Single Byte
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
51
AMC7812
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
www.ti.com
Writing Multiple Words to Different Registers (Figure 101)
A complete word must be written to a register (high byte and low byte) for proper operation.
1. The master device asserts a start condition.
2. The master then sends the 7-bit AMC7812 slave address followed by a zero for the direction bit, indicating a
write operation.
3. The AMC7812 asserts an acknowledge signal on SDA.
4. The master sends the first register address.
5. The AMC7812 asserts an acknowledge signal on SDA.
6. The master sends the high byte of the data word to the first register.
7. The AMC7812 asserts an acknowledge signal on SDA.
8. The master sends the low byte of the data word to the first register.
9. The AMC7812 asserts an acknowledge signal on SDA.
10. The master sends a second register address.
11. The AMC7812 asserts an acknowledge signal on SDA.
12. The master then sends the high byte of the data word to the second register.
13. The AMC7812 asserts an acknowledge on SDA.
14. The master sends the low byte of the data word to the second register.
15. The AMC7812 asserts an acknowledge signal on SDA.
16. The master and the AMC7812 repeat steps 4 to 15 until the last data are transferred.
17. The master then asserts a stop condition to end the transaction.
S
AMC7812
Slave Address
From Master to Slave
From Slave to Master
0
A
Register Pointer
(1st Register Address)
A
High Byte of Data to
1st Register
A
Low Byte of Data to
1st Register
A
Register Pointer
(2nd Register Address)
A
High Byte of Data to
2nd Register
A
Low Byte of Data to
2nd Register
A
Register Pointer
(Last Register Address)
A
High Byte of Data to
Last Register
A
Low Byte of Data to
Last Register
A
P
A = Acknowledge
N = Not Acknowledge
S = START Condition
P = Stop Condition
Sr = Repeated START Condition
Figure 101. Write to Multiple 16-Bit Registers
52
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
AMC7812
www.ti.com
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
Reading a Single Word from Any Register (Figure 102)
1. The master device asserts a start condition.
2. The master then sends the 7-bit AMC7812 slave address followed by a zero for the direction bit, indicating a
write operation.
3. The AMC7812 asserts an acknowledge signal on SDA.
4. The master sends a register address.
5. The AMC7812 asserts an acknowledge signal on SDA.
6. The master device asserts a restart condition.
7. The master then sends the 7-bit AMC7812 slave address followed by a '1' for the direction bit, indicating a
read operation.
8. The AMC7812 asserts an acknowledge signal on SDA.
9. The AMC7812 then sends the high byte of the register (D15:D8).
10. The master asserts an acknowledge signal on SDA.
11. The AMC7812 sends the low byte of the register (D7:D0).
12. The master asserts a not acknowledge signal on SDA.
13. The master then asserts a stop condition to end the transaction.
S
AMC7812
Slave Address
0
A
Register Pointer
(Register Address)
A
A
From High Byte of
AMC7812 Register
A
Sr
AMC7812
Slave Address
From Low Byte of
AMC7812 Register
1
N
P
A = Acknowledge
N = Not Acknowledge
S = START Condition
P = Stop Condition
Sr = Repeated START Condition
From Master to Slave
From Slave to Master
Figure 102. Read a Single Word
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
53
AMC7812
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
www.ti.com
Reading the Same Register Multiple Times (Figure 103 and Figure 104)
1. The master device asserts a start condition.
2. The master then sends the 7-bit AMC7812 slave address followed by a zero for the direction bit, indicating a
write operation.
3. The AMC7812 asserts an acknowledge signal on SDA.
4. The master sends a register address.
5. The AMC7812 asserts an acknowledge signal on SDA.
6. The master device asserts a restart condition.
7. The master then sends the 7-bit AMC7812 slave address followed by a '1' for the direction bit, indicating a
read operation.
8. The AMC7812 asserts an acknowledge signal on SDA.
9. The AMC7812 then sends the high byte of the register (D15:D8).
10. The master asserts an acknowledge signal on SDA.
11. The AMC7812 sends the low byte of the register (D7:D0).
12. The master asserts an acknowledge signal on SDA.
13. The AMC7812 and the master repeat steps 9 to 12 until the low byte of last reading is transferred.
14. After receiving the low byte of the last register, the master asserts a not acknowledge signal on SDA.
15. The master then asserts a stop condition to end the transaction.
S
AMC7812
Slave Address
From Master to Slave
From Slave to Master
0
A
Register Pointer
(Register Address)
A
A
High Byte of Register;
1st Reading
A
Low Byte of Register;
1st Reading
A
High Byte of Register;
Last Reading
A
Low Byte of Register;
Last Reading
N
AMC7812
Slave Address
Sr
1
P
A = Acknowledge
N = Not Acknowledge
S = START Condition
P = Stop Condition
Sr = Repeated START Condition
Figure 103. Read Multiple Words
54
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
AMC7812
www.ti.com
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
S
S
S
AMC7812
Slave Address
AMC7812
Slave Address
AMC7812
Slave Address
From Master to Slave
From Slave to Master
0
0
0
A
Register Pointer
(1st Register Address)
A
A
High Byte of
1st Register
A
A
Register Pointer
(2nd Register Address)
A
A
High Byte of
2nd Register
A
A
Register Pointer
(Last Register Address)
A
A
High Byte of the Last
Register being Read
A
Sr
AMC7812
Slave Address
Low Byte of
1st Register
Sr
N
AMC7812
Slave Address
Low Byte of
2nd Register
Sr
1
1
N
AMC7812
Slave Address
Low Byte of the Last
Register being Read
P
P
1
N
P
A = Acknowledge
N = Not Acknowledge
S = START Condition
P = Stop Condition
Sr = Repeated START Condition
Figure 104. Read Multiple Registers Using the Reading Single Word from Any Register Method
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
55
AMC7812
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
www.ti.com
Serial Peripheral Interface (SPI)
The AMC7812 can be controlled over a versatile 3-wire serial interface that operates at clock rates of up to
50MHz and is compatible with SPI, QSPI™, MICROWIRE™, and DSP standards. The SPI communication
command consists of a read/write bit, seven register address bits, and 16 data bits (as shown in Table 9), for a
total of 24 bits. The timing for this operation is shown in the SPI timing diagrams (Figure 3, Figure 4, and
Figure 5).
SPI Shift Register
The SPI shift register is 24 bits wide. Data are loaded into the device MSB first as a 24-bit word under the control
of the serial clock input, SCLK. The falling edge of CS starts the communication cycle. The data are latched into
the SPI shift register on the falling edge of SCLK, while CS is low. When CS is high, the SCLK and SDI signals
are blocked out and the SDO line is in a high-impedance state. The contents of the SPI shift register are loaded
into the device internal register on the rising edge of CS (with delay). During the transfer, the command is
decoded and the new data are transferred into the proper registers.
The serial interface works with both a continuous and non-continuous serial clock. A continuous SCLK source
can only be used if CS is held low for the correct number of clock cycles. In gated clock mode, a burst clock
containing the exact number of clock cycles must be used and CS must be taken high after the final clock to
latch the data.
AMC7812 Communications Command for SPI
The AMC7812 is entirely controlled by registers. Reading from and writing to these registers is accomplished by
issuing a 24-bit operation word shown in Table 9.
Table 9. 24-Bit Word Structure for Read/Write Operation
OPERATION
Write
Read frame 1
Read frame 2
Bit 23
I/O
BIT 23 (MSB)
BIT22:BIT16
BIT15:BIT0
SDI
0 (R/W)
Addr6:Addr0
Data to be written
SDO
Data is undefined
Data is undefined
Undefined or data depending on the
previous frame
SDI
1 (R/W)
Addr6:Addr0
don't care
SDO
Data is undefined
Data is undefined
Undefined or data depending on the
previous frame
SDI
1 (R/W)
Addr6:Addr0
don't care
SDO
Data is undefined
Data is undefined
Data for address specified in frame 1
R/W. Indicates a read from or a write to the addressed register.
Bit = '0' sets the write operation and the data are written to the specified register.
Bit = '1' sets the read operation where bits [addr6:addr0] select the register to be read. The remaining bits are don't care.
The data read from the selected register appear on SDO pin in the next SPI cycle.
Bits[22:16]
Addr6:Addr0. Register address; specifies which register is accessed.
Bits[15:0]
DATA. 16-bit data bits.
In write operation, these bits are written to bits[15:0] of the register with the address of [Addr6:Addr0].
In read operation, these bits are determined by previous operation. If previous operation is a read, these bits are from
bits[15:0] of the internal register specified in previous read operation. If previous operation is a write, these data bits are
don’t care (undefined). The data read from current read operation appears on SDO in the next operation cycle.
56
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
AMC7812
www.ti.com
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
Standalone Operation
In standalone mode, as shown in Figure 105, each AMC7812 has its own SPI bus. The serial clock can be
continuous or gated. The first falling edge of CS starts the operation cycle. Exactly 24 falling clock edges must be
applied before CS is brought high again. If CS is brought high before the 24th falling SCLK edge, or if more than
24 falling SCLK edges are applied before CS is brought high, then the input data are incorrect. The device input
register is updated from the Shift Register on the rising edge of CS, and data are automatically transferred to the
addressed registers as well. In order for another serial transfer to occur, CS must be brought low again.
Figure 106 and Figure 107 show write, and read operations in standalone mode.
SDO
SDI
SCLK
CS
AMC7812
Figure 105. Standalone Operation
CS
SDI
W0
SDO
W1
XX
W3
W2
XX
XX
XX
Wn = Write Command for Register N
XX = Don’t care, undefined
Figure 106. Write Operation in Standalone Mode
CS
SDI
SDO
R0
R1
D0
XX
R2
D1
Any Command
R3
D3
D2
Rn = Read Command for Register N
Dn = Data from Register N
XX = Don’t care, undefined
Figure 107. Read Operation in Standalone Mode
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
57
AMC7812
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
www.ti.com
Daisy-Chain Operation
For systems that contain several AMC7812s, the SDO pin can be used to daisy-chain multiple devices together.
This daisy-chain feature is useful in reducing the number of serial interface lines. The first falling edge of CS
starts the operation cycle. SCLK is continuously applied to the Input Shift Register when CS is low.
If more than 24 clock pulses are applied, the data ripple out of the Shift Register and appear on the SDO line.
These data are clocked out on the rising edge of SCLK and are valid on the falling edge. By connecting the SDO
output of the first device to the SDI input of the next device in the chain, a multiple-device interface is
constructed. Each device in the system requires 24 clock pulses. Therefore, the total number of clock cycles
must equal 24N, where N is the total number of AMC7812s in the daisy chain. When the serial transfer to all
devices is complete, CS is taken high. This action transfers the data from the SPI Shifter Registers to the internal
register of each AMC7812 in the daisy chain and prevents any further data from being clocked in. The serial
clock can be continuous or gated. A continuous SCLK source can only be used if CS is held low for the correct
number of clock cycles. In gated clock mode, a burst clock containing the exact number of clock cycles must be
used and CS must be taken high after the final clock in order to latch the data.
B
C
SDI
SDI-C
SDO-C
SDI-B
A
SDO-B
SDO-A
SDI-A
SDO
CS
SCLK
Figure 108. Three AMC7812s in a Daisy-Chain Configuration
Cycle 0
CS
Cycle 1
Cycle 2
Cycle 3
SDI-C
RA0
RB0
RC0
RA1
RB1
RC1
RA2
RB2
RC2
RA3
RB3
RC3
SDO-C
XX
RA0
RB0
CD0
RA1
RB1
CD1
RA2
RB2
CD2
RA3
RB3
SDI-B
XX
RA0
RB0
CD0
RA1
RB1
CD1
RA2
RB2
CD2
RA3
RB3
SDO-B
XX
XX
RA0
BD0
CD0
RA1
BD1
CD1
RA2
BD2
CD2
RA3
SDI-A
XX
XX
RA0
BD0
CD0
RA1
BD1
CD1
RA2
BD2
CD2
RA3
SDO-A
XX
XX
XX
AD0
BD0
CD0
AD1
BD1
CD1
AD2
BD2
CD2
RAn (RBn, RCn) = Read Command for Register N of device A (B,C)
ADn (BDn, CDn) = Data from Register N of device A (B, C)
XX = Don’t care, undefined
Figure 109. Reading Multiple Registers
58
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
AMC7812
www.ti.com
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
Cycle 0
CS
Cycle 1
Cycle 2
Cycle 3
SDI-C
RA0
WB0
RC0
RA1
WB1
WC1
RA2
RB2
RC2
RA3
RB3
RC3
SDO-C
XX
RA0
WB0
CD0
RA1
WB1
XX
RA2
RB2
CD2
RA3
RB3
SDI-B
XX
RA0
WB0
CD0
RA1
WB1
XX
RA2
RB2
CD2
RA3
RB3
SDO-B
XX
XX
RA0
XX
CD0
RA1
XX
XX
RA2
BD2
CD2
RA3
SDI-A
XX
XX
RA0
XX
CD0
RA1
XX
XX
RA2
BD2
CD2
RA3
SDO-A
XX
XX
XX
AD0
XX
CD0
AD1
XX
XX
AD2
BD2
CD2
WBn (WCn) = Write Command for Register N of device A (B,C)
RAn (RBn, RCn) = Read Command for Register N of device A (B, C)
ADn (BDn, CDn) = Data from Register N of device A (B, C)
XX = Don’t care, undefined
Figure 110. Mixed Operation: Reading Devices A and C, and Writing to Device B; then Reading A, and
Writing to B and C; then Reading A, B, and C Twice
Cycle 0
CS
Cycle 1
Cycle 2
Cycle 3
SDI-C
WA0
WB0
RC0
WA1
WB1
RC1
WA2
WB2
RC2
WA3
WB3
RC3
SDO-C
XX
WA0
WB0
CD0
WA1
WB1
CD1
WA2
WB2
CD2
WA3
WB3
SDI-B
XX
WA0
WB0
CD0
WA1
WB1
CD1
WA2
WB2
CD2
WA3
WB3
SDO-B
XX
XX
WA0
XX
CD0
WA1
XX
CD1
WA2
XX
CD2
WA3
SDI-A
XX
XX
WA0
XX
CD0
WA1
XX
CD1
WA2
XX
CD2
WA3
SDO-A
XX
XX
XX
XX
XX
CD0
XX
XX
CD1
XX
XX
CD2
Figure 111. Writing to Devices A and B, and Reading Device C
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
59
AMC7812
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
www.ti.com
REGISTERS
REGISTER MAP
The AMC7812 has several 16-bit registers that consist of a high byte (8 MSBs) and a low byte (8 LSBs). An 8-bit
register pointer points to the proper register. The pointer does not change after the operation. Table 10 lists the
registers for the AMC7812. Note that the default values are for SPI operation; see the register descriptions for
I2C default values.
Table 10. Register Map
ADDRESS
(HEX)
R/W
DEFAULT
(HEX)
00
R
0000
01
R
02
R
0A
R/W
0B
(1)
60
ADDRESS
(HEX)
R/W
DEFAULT
(HEX)
LT-Temperature-Data
45
R/W
0000
DAC-6-CLR-Setting
0000
D1-Temperature-Data
46
R/W
0000
DAC-7-CLR-Setting
0000
D2-Temperature-Data
47
R/W
0000
DAC-8-CLR-Setting
003C (1)
Temperature Configuration
48
R/W
0000
DAC-9-CLR-Setting
R/W
0007 (1)
Temperature Conversion Rate
49
R/W
0000
DAC-10-CLR-Setting
21
R/W
0000 (1)
η-Factor Correction (for D1)
4A
R/W
0000
DAC-11-CLR-Setting
22
R/W
0000 (1)
η-Factor Correction (for D2)
4B
R/W
000F
GPIO
23
R
0000
ADC-0-Data
4C
R/W
2000
AMC Configuration 0
24
R
0000
ADC-1-Data
4D
R/W
0070
AMC Configuration 1
25
R
0000
ADC-2-Data
4E
R/W
0000
Alarm Control
26
R
0000
ADC-3-Data
4F
R
0000
Status
27
R
0000
ADC-4-Data
50
R/W
0000
ADC Channel 0
28
R
0000
ADC-5-Data
51
R/W
0000
ADC Channel 1
29
R
0000
ADC-6-Data
52
R/W
FFFF
ADC Gain
2A
R
0000
ADC-7-Data
53
R/W
0004
AUTO-DAC-CLR-SOURCE
REGISTER
REGISTER
2B
R
0000
ADC-8-Data
54
R/W
0000
AUTO-DAC-CLR-EN
2C
R
0000
ADC-9-Data
55
R/W
0000
SW-DAC-CLR
2D
R
0000
ADC-10-Data
56
R/W
0000
HW-DAC-CLR-EN-0
2E
R
0000
ADC-11-Data
57
R/W
0000
HW-DAC-CLR-EN-1
2F
R
0000
ADC-12-Data
58
R/W
0000
DAC Configuration
30
R
0000
ADC-13-Data
59
R/W
0000
DAC Gain
31
R
0000
ADC-14-Data
5A
R/W
0FFF
Input-0-High-Threshold
32
R
0000
ADC-15-Data
5B
R/W
0000
Input-0-Low-Threshold
33
R/W
0000
DAC-0-Data
5C
R/W
0FFF
Input-1-High-Threshold
34
R/W
0000
DAC-1-Data
5D
R/W
0000
Input-1-Low-Threshold
35
R/W
0000
DAC-2-Data
5E
R/W
0FFF
Input-2-High-Threshold
36
R/W
0000
DAC-3-Data
5F
R/W
0000
Input-2-Low-Threshold
37
R/W
0000
DAC-4-Data
60
R/W
0FFF
Input-3-High-Threshold
38
R/W
0000
DAC-5-Data
61
R/W
0000
Input-3-Low-Threshold
39
R/W
0000
DAC-6-Data
62
R/W
07FF
LT-High-Threshold
3A
R/W
0000
DAC-7-Data
63
R/W
0800
LT-Low-Threshold
3B
R/W
0000
DAC-8-Data
64
R/W
07FF
D1-High-Threshold
3C
R/W
0000
DAC-9-Data
65
R/W
0800
D1-Low-Threshold
3D
R/W
0000
DAC-10-Data
66
R/W
07FF
D2-High-Threshold
3E
R/W
0000
DAC-11-Data
67
R/W
0800
D2-Low-Threshold
3F
R/W
0000
DAC-0-CLR-Setting
68
R/W
0810
Hysteresis-0
40
R/W
0000
DAC-1-CLR-Setting
69
R/W
0810
Hysteresis-1
41
R/W
0000
DAC-2-CLR-Setting
6A
R/W
2108
Hysteresis-2
42
R/W
0000
DAC-3-CLR-Setting
6B
R/W
0000
Power-Down
43
R/W
0000
DAC-4-CLR-Setting
6C
R
1220
Device ID
44
R/W
0000
DAC-5-CLR-Setting
7C
R/W
N/A
Software Reset
2
See register descriptions for I C default values.
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
AMC7812
www.ti.com
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
TEMPERATURE DATA REGISTERS (Read-Only)
In twos complement format, 0.125°C/LSB.
LT-Temperature-Data Register (Address = 00h, Default 0000h, 0°C)
Store the local temperature sensor reading in twos complement data format.
MSB
BIT 15 BIT 14 BIT 13 BIT 12 BIT 11 BIT 10
BIT 9
BIT 8
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
LSB
BIT 0
LT-11
LT-5
LT-4
LT-3
LT-2
LT-1
LT-0
0
0
0
0
LT-10
LT-9
LT-8
LT-7
LT-6
D1-Temperature-Data Register (Address = 01h, Default 0000h, 0°C)
Store the remote temperature sensor D1 reading in twos complement data format.
MSB
BIT 15 BIT 14 BIT 13 BIT 12 BIT 11 BIT 10
BIT 9
BIT 8
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
LSB
BIT 0
D1-11
D1-5
D1-4
D1-3
D1-2
D1-1
D1-0
0
0
0
0
D1-10
D1-9
D1-8
D1-7
D1-6
D2-Temperature-Data Register (Address = 02h, Default 0000h, 0°C)
Store the remote temperature sensor D2 reading in twos complement data format.
MSB
BIT 15 BIT 14 BIT 13 BIT 12 BIT 11 BIT 10
BIT 9
BIT 8
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
LSB
BIT 0
D2-11
D2-5
D2-4
D2-3
D2-2
D2-1
D2-0
0
0
0
0
D2-10
D2-9
D2-8
D2-7
D2-6
TEMPERATURE CONFIGURATION REGISTER (Read/Write, Address = 0Ah)
When using the SPI, the following bit configuration must be used; default = 003Ch.
MSB
BIT 15 BIT 14 BIT 13 BIT 12 BIT 11 BIT 10
0
0
0
0
0
0
BIT 9
BIT 8
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
LSB
BIT 0
0
0
0
0
D2EN
D1EN
LTEN
RC
0
0
When using the I2C interface, the following bit configuration must be used; default = 3CFFh.
MSB
BIT 15 BIT 14 BIT 13 BIT 12 BIT 11 BIT 10
0
0
D2EN
D1EN
LTEN
RC
BIT 9
BIT 8
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
LSB
BIT 0
0
0
1
1
1
1
1
1
1
1
The bit descriptions are shown in Table 11.
Table 11. Temperature Configuration Register Bit Descriptions
NAME
DEFAULT
R/W
DESCRIPTION
D2EN
1
R/W
Remote temperature sensor D2 enable.
If this bit = '1', D2 is enabled.
If this bit = '0', D2 is disabled.
D1EN
1
R/W
Remote temperature sensor D1 enable.
If this bit = '1', D1 is enabled.
If this bit = '0', D1 is disabled.
LTEN
1
R/W
Local temperature sensor enable.
If this bit = '1', LT is enabled.
If this bit = '0', LT is disabled.
RC
1
R/W
Resistance correction enable.
If this bit = '1', correction is enabled.
If this bit = '0', correction is disabled.
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
61
AMC7812
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
www.ti.com
TEMPERATURE CONVERSION RATE REGISTER (Read/Write, Address = 0Bh)
When using the SPI, the following bit configuration must be used; default = 0007h.
MSB
BIT 15 BIT 14 BIT 13 BIT 12 BIT 11 BIT 10
0
0
0
0
0
0
BIT 9
BIT 8
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
LSB
BIT 0
0
0
0
0
0
0
0
R2
R1
R0
When using the I2C interface, the following bit configuration must be used; default = 07FFh.
MSB
BIT 15 BIT 14 BIT 13 BIT 12 BIT 11 BIT 10
0
0
0
0
0
R2
BIT 9
BIT 8
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
LSB
BIT 0
R1
R0
1
1
1
1
1
1
1
1
The bit descriptions are shown in Table 12.
Table 12. Temperature Conversion Time
R2
R1
R0
CONVERSION TIME
0
0
0
128x minimum
0
0
1
64x minimum
0
1
0
32x minimum
0
1
1
16x minimum
1
0
0
8x minimum
1
0
1
4x minimum
1
1
0
2x minimum
1
1
1
Minimum cycle time
Table 13. Temperature Monitoring Cycle Time
MONITORING
CYCLE TIME
TEMPERATURE SENSOR STATUS
Local sensor is active, remote sensors are disabled or in power-down.
15ms
One remote sensor is active and RC = '0', local sensor and one remote sensor are disabled or in power-down.
44ms
One remote sensor is active and RC = '1', local sensor and one remote sensor are disabled or in power-down.
93ms
One remote sensor and local sensor are active and RC = '0', one remote sensor is disabled or in power-down.
59ms
One remote sensor and local sensor are active and RC = '1', one remote sensor is disabled or in power-down.
108ms
Two remote sensors are active and RC = '0', local sensor is disabled or in power-down.
88ms
Two remote sensors are active and RC = '1', local sensor is disabled or in power-down.
186ms
All sensors are active and RC = '0'.
103ms
All sensors are active and RC = '1'.
201ms
62
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
AMC7812
www.ti.com
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
η-FACTOR CORRECTION REGISTER (Read/Write, Addresses = 21h and 22h)
Only the low byte is used; the high byte is ignored.
When using the SPI interface, the following bit configuration must be used; (Default = 0000h).
MSB
BIT 15 BIT 14 BIT 13 BIT 12 BIT 11 BIT 10
0
0
0
0
0
BIT 9
BIT 8
0
0
0
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
LSB
BIT 0
NADJUST
When using the I2C, the following bit configuration must be used; (Default = 00FFh).
MSB
BIT 15 BIT 14 BIT 13 BIT 12 BIT 11 BIT 10
BIT 9
NADJUST
BIT 8
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
LSB
BIT 0
1
1
1
1
1
1
1
1
The NADJUST value for ideality correction is stored as shown in Table 14. ηEFF is the actual ideality of the
transistor being used. Refer to the Ideality Factor section for more details.
Table 14. NADJUST and ηEFF Values
NADJUST
BINARY
HEX
DECIMAL
ηEFF
0111 1111
7F
127
1.747977
0000 1010
0A
10
1.042759
0000 1000
08
8
1.035616
0000 0110
06
6
1.028571
0000 0100
04
4
1.021622
0000 0010
02
2
1.014765
0000 0001
01
1
1.011371
0000 0000
00
0
1.008 (Default)
1111 1111
FF
–1
1.004651
1111 1110
FE
–2
1.001325
1111 1100
FC
–4
0.994737
1111 1010
FA
–6
0.988235
1111 1000
F8
–8
0.981818
1111 0110
F6
–10
0.975484
1000 0000
80
–128
0.706542
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
63
AMC7812
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
www.ti.com
ADC-n-DATA REGISTERS (Read-Only, Addresses = 23h to 32h)
MSB
BIT 15 BIT 14 BIT 13 BIT 12 BIT 11 BIT 10
0
0
Bits[11:0]
0
0
A11
A10
BIT 9
BIT 8
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
LSB
BIT 0
A9
A8
A7
A6
A5
A4
A3
A2
A1
A0
ADC data.
Four ADC data registers are available. The ADC-n-Data Registers (where n = 0 to 15) store the conversion
results of the corresponding analog channel-n, as shown in Table 15.
Table 15. ADC Data Register Definitions
64
INPUT CHANNEL
INPUT TYPE
CONVERSION RESULT
STORED IN
FORMAT
Channel 0
Single-Ended
ADC-0-Data Register
Straight binary
Channel 1
Single-Ended
ADC-1-Data Register
Straight binary
Channel 2
Single-Ended
ADC-2-Data Register
Straight binary
Channel 3
Single-Ended
ADC-3-Data Register
Straight binary
CH0+/CH1–
Differential
ADC-0-Data Register
Twos complement
CH2+/CH3–
Differential
ADC-2-Data Register
Twos complement
Channel 4
Single-Ended
ADC-4-Data Register
Straight binary
Channel 5
Single-Ended
ADC-5-Data Register
Straight binary
Channel 6
Single-Ended
ADC-6-Data Register
Straight binary
Channel 7
Single-Ended
ADC-7-Data Register
Straight binary
Channel 8
Single-Ended
ADC-8-Data Register
Straight binary
Channel 9
Single-Ended
ADC-9-Data Register
Straight binary
Channel 10
Single-Ended
ADC-10-Data Register
Straight binary
Channel 11
Single-Ended
ADC-11-Data Register
Straight binary
Channel 12
Single-Ended
ADC-12-Data Register
Straight binary
Channel 13
Single-Ended
ADC-13-Data Register
Straight binary
Channel 14
Single-Ended
ADC-14-Data Register
Straight binary
Channel 15
Single-Ended
ADC-15-Data Register
Straight binary
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
AMC7812
www.ti.com
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
DAC-n-DATA REGISTERS (Read/Write, Addresses = 33h to 3Eh, Default 0000h)
Each DAC has a DAC data register to store the data [DAC11:DAC0] that is loaded into the DAC Latches.
MSB
BIT 15 BIT 14 BIT 13 BIT 12 BIT 11 BIT 10
0
0
Bits[11:0]
0
0
D11
D10
BIT 9
BIT 8
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
LSB
BIT 0
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
DAC data.
DAC-n-CLR-SETTING REGISTERS (Read/Write, Addresses = 3Fh to 4Ah, Default 0000h)
Each DAC has a DAC-CLR-Setting Register to store the data to be loaded into the DAC Latch when the DAC is
cleared.
MSB
BIT 15 BIT 14 BIT 13 BIT 12 BIT 11 BIT 10
0
0
0
0
DCLR
11
DCLR
10
BIT 9
BIT 8
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
LSB
BIT 0
DCLR
9
DCLR
8
DCLR
7
DCLR
6
DCLR
5
DCLR
4
DCLR
3
DCLR
2
DCLR
1
DCLR
0
GPIO REGISTER (Read/Write, Address = 4Bh, Default = 000Fh)
MSB
BIT 15 BIT 14 BIT 13 BIT 12 BIT 11 BIT 10
0
0
0
0
0
0
BIT 9
BIT 8
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
LSB
BIT 0
0
0
GPIO7
GPIO6
GPIO5
GPIO4
GPIO3
GPIO2
GPIO1
GPIO0
For write operations, the GPIO pin operates as an output. Writing a '1' to the GPIO-n bit sets the GPIO-n pin to
high impedance. Writing a '0' sets the GPIO-n pin to logic low. An external pull-up resistor is required when using
the GPIO pin as an output.
For read operations, the GPIO pin operates as an input. Read the GPIO-n bit to receive the status of the GPIO-n
pin. Reading a '0' indicates that the GPIO-n pin is low; reading a '1' indicates that the GPIO-n pin is high.
After power-on reset, or any forced hardware or software reset, the GPIO-n bit is set to '1' and is in a highimpedance state.
When D1 is enabled, GPIO-4 and GPIO-5 are ignored.
When D2 is enabled, GPIO-6 and GPIO-7 are ignored.
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
65
AMC7812
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
www.ti.com
AMC CONFIGURATION REGISTER 0 (Read/Write, Address = 4Ch, Default = 2000h)
Table 16. AMC Configuration Register 0
BIT
NAME
DEFAULT
R/W
15
—
0
R
Reserved. Writing to this bit causes no change. Reading this bit returns '0'.
14
—
0
R
Reserved. Writing to this bit causes no change. Reading this bit returns '0'.
13
CMODE
1
R/W
ADC Conversion Mode Bit. This bit selects between the two operating conversion modes
(direct or auto).
CMODE = '0': Direct mode. The analog inputs specified in the ADC Channel Registers are
converted sequentially (see the ADC Channel Registers) one time. When one set of
conversions is complete, the ADC is idle and waits for a new trigger.
CMODE = '1': Auto mode. The analog inputs specified in the AMC Channel Registers are
converted sequentially and repeatedly (see the ADC Channel Registers). When one set of
conversions is complete, the ADC multiplexer returns to the first channel and repeats the
process. Repetitive conversions continue until the CMODE bit is cleared ('0').
12
ICONV
0
R/W
Internal conversion bit.
Set this bit to '1' to start the ADC conversion internally. The bit is automatically cleared ('0')
after the ADC conversion starts.
R/W
Load DAC bit. Set this bit to '1' to synchronously load the DAC Data Registers, which are
programmed for synchronous update mode (SLDAC-n = 1). The AMC7812 updates the
DAC Latch only if the ILDAC bit is set ('1'), thereby eliminating any unnecessary glitch. Any
DAC channels that have not been accessed are not reloaded. When the DAC Latch is
updated, the corresponding output changes to the new level immediately. This bit is
cleared ('0') after the DAC Data Register is updated.
11
66
DESCRIPTION
ILDAC
0
10
ADC-REF-INT
0
R/W
ADC VREF select bit.
When this bit = '0', the internal reference buffer is off, and the external reference drives the
ADC.
When this bit = '1', the internal buffer is on and the internal reference drives the ADC. Note
that a compensation capacitor is required.
9
EN-ALARM
0
R/W
Enable ALARM pin bit.
When this bit = '0', the ALARM pin is disabled.
When this bit = '1', the ALARM pin is enabled.
8
—
0
R
Reserved. Writing to this bit causes no change. Reading this bit returns '0'.
R
ADC Data available flag bit. For Direct mode only. Always cleared (set to '0') in Auto mode.
DAVF = '1': The ADC conversions are complete and new data are available.
DAVF = '0': The ADC conversion is in progress (data are not ready) or the ADC is in Auto
mode.
In Direct mode, the DAVF bit sets the DAV pin. DAV goes low when DAVF = '1', and goes
high when DAVF = '0'.
In Auto mode, DAVF is always cleared to '0'. However, a 1µs pulse (active low) appears on
the DAV pin when the last input specified in the ADC Channel Registers is converted.
DAVF is cleared to '0' in one of three ways: (1) reading the ADC Data Register, (2) starting
a new ADC conversion, or (3) writing '0' to this bit. Reading the Status Register does not
clear this bit.
7
DAVF
6
GALR
0
R
Global alarm bit. This bit is the OR function of all individual alarm bits of the Status
Register. This bit is set ('1') when any alarm condition occurs, and remains '1' until the
Status Register is read. This bit is cleared ('0') after reading the Status Register.
5
—
0
R
Reserved. Writing to this bit causes no change. Reading this bit returns '0'.
4
—
0
R
Reserved. Writing to this bit causes no change. Reading this bit returns '0'.
3
—
0
R
Reserved. Writing to this bit causes no change. Reading this bit returns '0'.
2
—
0
R
Reserved. Writing to this bit causes no change. Reading this bit returns '0'.
1
—
0
R
Reserved. Writing to this bit causes no change. Reading this bit returns '0'.
0
—
0
R
Reserved. Writing to this bit causes no change. Reading this bit returns '0'.
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
AMC7812
www.ti.com
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
AMC CONFIGURATION REGISTER 1 (Read/Write, Address = 4Dh, Default = 0070h)
Table 17. AMC Configuration Register 1
BIT
NAME
DEFAULT
R/W
15
—
0
R
Reserved. Writing to this bit causes no change. Reading this bit returns '0'.
DESCRIPTION
14
—
0
R
Reserved. Writing to this bit causes no change. Reading this bit returns '0'.
13
—
0
R
Reserved. Writing to this bit causes no change. Reading this bit returns '0'.
12
—
0
R
Reserved. Writing to this bit causes no change. Reading this bit returns '0'.
11
—
0
R
Reserved. Writing to this bit causes no change. Reading this bit returns '0'.
10
—
0
R
Reserved. Writing to this bit causes no change. Reading this bit returns '0'.
9
CONV-RATE-1
0
R/W
ADC conversion rate bit. See Table 18.
8
CONV-RATE-0
0
R/W
ADC conversion rate bit. See Table 18.
7
CH-FALR- CT-2
0
R/W
False alarm protection bit for CH0 to CH3. See Table 19.
6
CH-FALR- CT-1
1
R/W
False alarm protection bit for CH0 to CH3. See Table 19.
5
CH-FALR- CT-0
1
R/W
False alarm protection bit for CH0 to CH3. See Table 19.
4
TEMP-FALR- CT-1
1
R/W
False alarm protection bit for temperature monitor. See Table 20.
3
TEMP-FALR- CT-0
0
R/W
False alarm protection bit for temperature monitor. See Table 20.
2
—
0
R
Reserved. Writing to this bit causes no change. Reading this bit returns '0'.
1
—
0
R
Reserved. Writing to this bit causes no change. Reading this bit returns '0'.
0
—
0
R
Reserved. Writing to this bit causes no change. Reading this bit returns '0'.
Table 18. CONV-RATE-[1:0] Bit Settings
CONV-RATE-1
CONV-RATE-0
ADC CONVERSION RATE
0
0
500 kSPS, the specified rate (default)
0
1
½ of the specified rate
1
0
1/4 of the specified rate
1
1
1/8 of the specified rate
Table 19. CH-FALR-CT-[2:0] Bit Settings
CH-FALR-CT-2
CH-FALR-CT-1
CH-FALR-CT-0
N CONSECUTIVE SAMPLES
BEFORE ALARM IS SET
0
0
0
1
0
0
1
4
0
1
0
8
0
1
1
16 (default for CH-0 to CH-3)
1
0
0
32
1
0
1
64
1
1
0
128
1
1
1
256
Table 20. TEMP-FALR-CT-[1:0] Bit Settings
TEMP-FALR-CT-1
TEMP-FALR-CT-0
N CONSECUTIVE SAMPLES BEFORE ALARM IS SET
0
0
1
0
1
2
1
0
4 (default)
1
1
8
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
67
AMC7812
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
www.ti.com
ALARM CONTROL REGISTER (Read/Write, Address = 4Eh, Default = 0000h)
The Alarm Control Register determines whether the ALARM pin is accessed when a corresponding alarm event
occurs. However, this register does not affect the status bit in the Status Register. Note that the thermal alarm is
always enabled. When the THERM_ALR bit = '1', the ALARM pin goes low, if the pin is enabled.
Table 21. Alarm Control Register
BIT
NAME
DEFAULT
R/W
15
—
0
R
14
13
12
11
10
9
8
7
6
5
4
68
EALR-CH0
EALR-CH1
EALR-CH2
EALR-CH3
EALR-LT-Low
EALR-LT-High
EALR-D1-Low
EALR-D1-High
EALR-D2-Low
EALR-D2-High
EALR-D1-FAIL
0
0
0
0
0
0
0
0
0
0
0
DESCRIPTION
Reserved. Writing to this bit causes no change. Reading this bit returns '0'.
R/W
CH0 and (CH0+/CH1–) alarm enable bit.
If EALR-CH0 = '1', the alarm is enabled, the CH0-ALR bit is set, and the ALARM pin goes
low (if enabled) when the input of CH0 or (CH0+/CH1–) is out of range.
If EALR-CH0 = '0', the alarm is masked. When the input of CH0 or (CH0+/CH1–) is out of
range, the ALARM pin does not go low, but the CH0-ALR bit is set.
R/W
CH1 alarm enable bit.
If EALR-CH1 = '1', the alarm is enabled, the CH1-ALR bit is set, and the ALARM pin goes
low (if enabled) when the input of CH1 is out of range.
If EALR-CH1 = '0', the alarm is masked. When the input of CH1 is out of range, the
ALARM pin does not go low, but the CH1-ALR bit is set.
R/W
CH2 and (CH2+/CH3–) alarm enable bit.
If EALR-CH2 = '1', the alarm is enabled, the CH2-ALR bit is set, and the ALARM pin goes
low (if enabled) when the input of CH2 or (CH2+/CH3–) is out of range.
If EALR-CH2 = '0', the alarm is masked. When the input of CH2 or (CH2+/CH3–) is out of
range, the ALARM pin does not go low, but the CH2-ALR bit is set.
R/W
CH3 alarm enable bit.
If EALR-CH3 = '1', the alarm is enabled, the CH3-ALR bit is set, and the ALARM pin goes
low (if enabled) when the input of CH3 is out of range.
If EALR-CH3 = '0', the alarm is masked. When the input of CH3 is out of range, the
ALARM pin does not go low, but the CH3-ALR bit is set.
R/W
Local sensor low alarm enable bit.
If EALR-LT-Low = '1', the LT-Low alarm is enabled. When LT is below the specified range,
the LT-Low-ALR bit is set ('1') and the ALARM pin goes low (if enabled).
If EALR-LT-Low = '0', the LT-Low alarm is masked. When LT is below the specified range,
the ALARM pin does not go low, but the LT-Low-ALR bit is set.
R/W
Local sensor high alarm enable bit.
If EALR-LT-High = '1', the LT-High alarm is enabled. When LT is above the specified
range, the LT-High-ALR bit is set ('1') and the ALARM pin goes low (if enabled).
If EALR-LT-High = '0', the LT-High alarm is masked. When LT is above the specified
range, the ALARM pin does not go low, but the LT-High-ALR bit is set.
R/W
D1 low alarm enable bit.
If EALR-D1-Low = '1', the D1-Low alarm is enabled. When D1 is below the specified range,
the D1-Low-ALR bit is set ('1'), and the ALARM pin goes low (if enabled).
If EALR-D1-Low = '0', the D1-Low alarm is masked. When D1 is below the specified range,
the ALARM pin does not go low, but the D1-Low-ALR bit is set.
R/W
D1 high alarm enable bit.
If EALR-D1-High = '1', the D1-High alarm is enabled. When D1 is above the specified
range, the D1-High-ALR bit is set ('1'), and the ALARM pin goes low (if enabled).
If EALR-D1-High = '0', the D1-High alarm is masked. When D1 is above the specified
range, the ALARM pin does not go low, but the D1-High-ALR bit is set.
R/W
D2 low alarm enable bit.
If EALR-D2-Low = '1', the D2-Low alarm is enabled. When D2 is below the specified range,
the D2-Low-ALR bit is set ('1'), and the ALARM pin goes low (if enabled).
If EALR-D2-Low = '0', the D2-Low alarm is masked. When D2 is below the specified range,
the ALARM pin does not go low, but the D2-Low-ALR bit is set.
R/W
D2 high alarm enable bit.
If EALR-D2-High = '1', the D2-High alarm is enabled. When D2 is above the specified
range, the D2-High-ALR bit is set ('1'), and the ALARM pin goes low (if enabled).
If EALR-D2-High = '0', the D2-High alarm is masked. When D2 is above the specified
range, the ALARM pin does not go low, but the D2-High-ALR bit is set.
R/W
D1 fail alarm enable bit.
If EALR-D1-FAIL = '1', the D1-Fail alarm is enabled. When D1 fails, the D1-FAIL-ALR bit is
set ('1'), the ALARM pin goes low (if enabled).
If EALR-D1-FAIL = '0', the D1-FAIL alarm is masked. When D1 fails, the ALARM pin does
not go low, but the D1-FAIL-ALR bit is set.
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
AMC7812
www.ti.com
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
Table 21. Alarm Control Register (continued)
BIT
3
NAME
EALR-D2-FAIL
DEFAULT
0
R/W
DESCRIPTION
R/W
D2 fail alarm enable bit.
If EALR-D2-FAIL = '1', the D2-Fail alarm is enabled. When D2 fails, the D2-FAIL-ALR bit is
set ('1'), the ALARM pin goes low (if enabled).
If EALR-D2-FAIL = '0', the D2-FAIL alarm is masked. When D2 fails, the ALARM pin does
not go low, but the D2-FAIL-ALR bit is set.
Alarm latch disable bit.
When ALARM-LATCH-DIS = '1', the Status Register bits are not latched. When the alarm
condition subsides, the alarm bits are cleared regardless of whether the Status Register
has been read or not.
When ALARM-LATCH-DIS = '0', the Status Register bits are latched. When an alarm
occurs, the corresponding alarm bit is set ('1'). The alarm bit remains '1' until the error
condition subsides and the Status Register is read. Before reading, the alarm bit is not
cleared ('0') even if the alarm condition disappears.
2
ALARMLATCH-DIS
0
R/W
1
—
0
R
Reserved. Writing to this bit causes no change. Reading this bit returns '0'.
0
—
0
R
Reserved. Writing to this bit causes no change. Reading this bit returns '0'.
STATUS REGISTER (Read Only, Address = 4Fh, Default = 0000h)
The AMC7812 continuously monitors all analog inputs and temperatures during normal operation. When any
input is out of the specified range N consecutive times, the corresponding alarm bit is set ('1'). If the input returns
to the normal range before N consecutive times, the corresponding alarm bit remains clear ('0'). This
configurations avoids any false alarms.
When an alarm status occurs, the corresponding alarm bit is set ('1'). When the ALARM-LATCH-DIS bit in the
Alarm Control Register is cleared ('0'), the ALARM pin is latched. Whenever an alarm status bit is set, it remains
set until the event that caused it is resolved and the Status Register is read. Reading the Status Registers clears
the alarm status bit. The alarm bit can only be cleared by reading the Status Register after the event is resolved,
or by hardware reset, software reset, or power-on reset. All alarm status bits are cleared when reading the Status
Register, and all these bits are reasserted if the out-of-limit condition still exists after the next conversion cycle,
unless otherwise noted.
When the ALARM-LATCH-DIS bit in the Alarm Control Register is set ('1'), the ALARM pin is not latched. The
alarm bit goes to '0' when the error condition subsides, regardless of whether the bit is read or not.
Table 22. Status Register
BIT
NAME
DEFAULT
R/W
15
—
0
R
Reserved. Writing to this bit causes no change. Reading this bit returns '0'.
14
CH0-ALR
0
R
CH0-ALR = '1' when single-ended channel 0 or differential input pair (CH0+/CH1–) is out of
the range defined by the corresponding threshold registers.
CH0-ALR = '0' when the analog input is not out of the specified range.
13
CH1-ALR
0
R
CH1-ALR = '1' when single-ended channel 1 is out of the range defined by the
corresponding threshold registers.
CH1-ALR = '0' when the analog input is not out of the specified range.
12
CH2-ALR
0
R
CH2-ALR = '1' when single-ended channel 2 or differential input pair (CH2+/CH3–) is out of
the range defined by the corresponding threshold registers.
CH2-ALR = '0' when the analog input is not out of the specified range.
11
CH3-ALR
0
R
CH3-ALR = '1' when single-ended channel 3 is out of the range defined by the
corresponding threshold registers.
CH3-ALR = '0' when the analog input is not out of the specified range.
R
Local temperature under-range flag.
LT-Low-ALR = '1' when the local temperature is less than the low-bound threshold.
LT-Low-ALR = '0' when the local temperature is not less than the range.
This bit is only checked when LT is enabled (EN-LT = '1'); it is ignored when EN-LT = '0'.
R
Local temperature over-range flag.
LT-High-ALR = '1' when the local temperature is greater than the high-bound threshold.
LT-High-ALR = '0' when the local temperature is not greater than the range.
This bit is only checked when LT is enabled (EN-LT = '1'); it is ignored when EN-LT = '0'.
10
9
LT-Low-ALR
LT-High-ALR
0
0
DESCRIPTION
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
69
AMC7812
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
www.ti.com
Table 22. Status Register (continued)
BIT
70
NAME
DEFAULT
R/W
DESCRIPTION
8
D1-Low-ALR
0
R
Remote temperature reading of D1when less than the range flag.
D1-Low-ALR = '1' when the local temperature is less than the low-bound threshold.
D1-Low-ALR = '0' when the local temperature is not less than the range.
This bit is only checked when D1 is enabled (EN-D1 = '1'); it is ignored when EN-D1 = '0'.
7
D1-High -ALR
0
R
Remote temperature reading of D1 when greater than the range flag.
D1-High-ALR = '1' when the local temperature is greater than the high-bound threshold.
D1-High-ALR = '0' when the local temperature is not greater than the range.
This bit is only checked when D1 is enabled (EN-D1 = '1'); it is ignored when EN-D1 = '0'.
6
D2-Low-ALR
0
R
Remote temperature reading of D2 when less than the range flag.
D2-Low-ALR = '1' when the local temperature is less than the low-bound threshold.
D2-Low-ALR = '0' when the local temperature is not less than the range.
This bit is only checked when D2 is enabled (EN-D2 = '1'); it is ignored when EN-D2 = '0'.
5
D2-High -ALR
0
R
Remote temperature reading of D2 when greater than the range flag.
D2-High-ALR = '1' when the local temperature is greater than the high-bound threshold.
D2-High-ALR = '0' when the local temperature is not greater than the range.
This bit is only checked when D2 is enabled (EN-D2 = '1'); it is ignored when EN-D2 = '0'.
4
D1-FAIL-ALR
0
R
Remote sensor D1 failure flag.
D1-FAIL-ALR = '1' when the sensor is an open-circuit or short-circuit.
D1-FAIL-ALR = '0' when the sensor is in a normal condition.
This bit is only checked when D1 is enabled (EN-D1 = '1'); it is ignored when EN-D1 = '0'.
3
D2-FAIL-ALR
0
R
Remote sensor D2 failure flag.
D2-FAIL-ALR = '1' when the sensor is an open-circuit or short-circuit.
D2-FAIL-ALR = '0' when the sensor is in a normal condition.
This bit is only checked when D2 is enabled (EN-D2 = '1'); it is ignored when EN-D2 = '0'.
2
THERM-ALR
0
R
Thermal alarm flag. When the die temperature is equal to or greater than +150°C, the bit is
set ('1') and the THERM-ALR flag activates. The on-chip temperature sensor (LT) monitors
the die temperature. If LT is disabled, the THERM-ALR bit is always '0'. The hysteresis of
this alarm is 8°C.
1
—
0
R
Reserved. Writing to this bit causes no change. Reading this bit returns '0'.
0
—
0
R
Reserved. Writing to this bit causes no change. Reading this bit returns '0'.
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
AMC7812
www.ti.com
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
ADC CHANNEL REGISTER 0 (Read/Write, Address = 50h, Default = 0000h)
MSB
BIT 15 BIT 14 BIT 13
0
SE0
BIT 12
DF
(CH0+/
CH1–)
SE1
BIT 9
BIT 8
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
LSB
BIT 0
DF
(CH2+/
CH3–)
SE4
SE5
SE6
SE7
SE8
SE9
SE10
SE11
SE12
BIT 11 BIT 10
SE2
SE3
These bits specify the external analog auxiliary input channels (CH0 to CH12) to be converted. The specified
channel(s) is accessed sequentially in order from bit 14 to bit 0. The input is converted when the corresponding
bit is set ('1').
Bit 15
Reserved. Writing to this bit causes no change. Reading this bit returns '0'.
Bits 14, 13, 11, 10, 8:0
SE0 to SE12. External single-ended analog input for CHn. The result is stored in ADC-n-Data Register in
straight binary format.
Bit 12
DF (CH0+CH1–). External analog differential input pair, CH0 and CH1, with CH0 as positive and CH1 as
negative. The difference of (CH0 – CH1) is converted and the result is stored in the ADC-0-Data Register in twos
complement format.
DF(CH2+/CH3-). External analog differential input pair, CH2 and CH3, with CH2 as positive and CH3 as
negative. The difference of (CH2 – CH3) is converted and the result is stored in the ADC-2-Data Register in twos
complement format.
Bit 9
Table 23. CH0 and CH1 Bit Settings
BIT 14
BIT 13
BIT 12
1
1
0
CH0 and CH1 are both accessed as single-ended inputs. Bit 12 is ignored.
DESCRIPTION
1
0
0
CH0 is accessed as a single-ended input. CH1 is not accessed. Bit 12 is ignored.
0
1
0
CH1 is accessed as a singled-ended. CH0 is not accessed. Bit 12 is ignored.
0
0
1
Differential input pair CH0 + and CH1– is accessed as a differential input.
0
0
0
CH0, CH1, and differential pair CH0+/CH1– are not accessed.
Table 24. CH2 and CH3 Bit Settings
BIT 11
BIT 10
BIT 9
1
1
0
CH2 and CH3 are both accessed as single-ended inputs. Bit 9 is ignored.
DESCRIPTION
1
0
0
CH2 is accessed as a single-ended input. CH3 is not accessed. Bit 9 is ignored.
0
1
0
CH3 is accessed as a singled-end input. CH2 is not accessed. Bit 9 is ignored.
0
0
1
Differential input pair CH2+ and CH3– is accessed as a differential input.
0
0
0
CH2, CH3, and differential pair CH2+/CH3– are not accessed.
Table 25. CH4 to CH12 Bit Settings
BIT 8
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
DESCRIPTION
1
—
—
—
—
—
—
—
—
CH4 is accessed as a single-ended input
—
1
—
—
—
—
—
—
—
CH5 is accessed as a single-ended input
—
—
1
—
—
—
—
—
—
CH6 is accessed as a single-ended input
—
—
—
1
—
—
—
—
—
CH7 is accessed as a single-ended input
—
—
—
—
1
—
—
—
—
CH8 is accessed as a single-ended input
—
—
—
—
—
1
—
—
—
CH9 is accessed as a single-ended input
—
—
—
—
—
—
1
—
—
CH10 is accessed as a single-ended input
—
—
—
—
—
—
—
1
—
CH11 is accessed as a single-ended input
—
—
—
—
—
—
—
—
1
CH12 is accessed as a single-ended input
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
71
AMC7812
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
www.ti.com
ADC CHANNEL REGISTER 1 (Read/Write, Address = 51h, Default = 0000h)
MSB
BIT 15 BIT 14 BIT 13 BIT 12 BIT 11 BIT 10
0
SE13
SE14
SE15
0
BIT 9
BIT 8
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
LSB
BIT 0
0
0
0
0
0
0
0
0
0
0
0
These bits specify the external analog auxiliary input channels (CH13, CH14,and CH 15) to be converted. The
specified channel is accessed sequentially in the order from bit 14 to bit 0 of ADC Channel Register 0, and then
bit 14 to bit 12 of ADC Channel Register 1. The input is converted when the corresponding bit is set ('1').
Bits[14:12]
SEn: External single-ended analog input CHn. The result is stored in the ADC-n-Data Register in straight binary format.
ADC GAIN REGISTER (Read/Write, Address = 52h, Default = FFFFh)
MSB
BIT
15
BIT
14
BIT
13
BIT
12
BIT
11
BIT
10
BIT 9
BIT 8
BIT 7
BIT 6
ADG0 ADG1 ADG2 ADG3 ADG4 ADG5 ADG6 ADG7 ADG8 ADG9
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
LSB
BIT 0
ADG10
ADG11
ADG12
ADG13
ADG14
ADG15
Bit 15
ADG0.
When ADG0 = '1', the analog input range of single-ended input CH0 (SE0) is 0 to (2 · VREF) or differential input pair
DF(CH0+/CH1–) is (–2 · VREF) to (+2 · VREF).
When ADG0 = '0', the analog input range of single-ended input CH0 (SE0) is 0 to VREF or differential input pair
DF(CH0+/CH1–) is –VREF to +VREF.
Bit 14
ADG1.
When ADG1 = '1', the analog input range is 0 to (2 · VREF).
When ADG1 = '0', the analog input range of single-ended input CH1 (SE1) is 0 to VREF.
Bit 13
ADG2.
When ADG2 = '1', the analog input range of single-ended input CH2 (SE2) is 0 to (2 · VREF) or differential input pair
DF(CH2+/CH3–) is (–2 · VREF) to (+2 · VREF).
When ADG2 = '0', the analog input range of single-ended input CH2 (SE2) is 0 to VREF or differential input pair
DF(CH2+/CH3–) is –VREF to +VREF.
Bit 12
ADG3.
When ADG3 = '1', the analog input range is 0 to (2 · VREF).
When ADG3 = '0', the analog input range of single-end input CH3 (SE3) is 0 to VREF.
Bit[11:0]
ADG4 to ADG15.
When these bits = '1', the analog input range is 0 to (2 · VREF).
When these bits = '0', the analog input range of CHn (where n = 4 to 15) is 0 to VREF
AUTO-DAC-CLR-SOURCE REGISTER (Read/Write, Address = 53h, Default = 0004h)
This register selects which alarm forces the DAC into a clear state, regardless of which DAC operation mode is
active, auto or manual.
Table 26. AUTO-DAC-CLR-SOURCE Register
BIT
NAME
DEFAULT
R/W
15
—
0
R
14
13
12
72
CH0-ALR-CLR
CH1-ALR-CLR
CH2-ALR-CLR
0
0
0
DESCRIPTION
Reserved. Writing to this bit causes no change. Reading this bit returns '0'.
R/W
CH0 alarm clear bit.
If CH0-ALR_CLR = '1', and if both the ACLRn bit in the AUTO-DAC-CLR-EN Register and
the CH0-ALR bit in the Status Register are set ('1'), then DAC-n is forced to a clear status.
If CH0-ALR_CLR = '0', then CH1-ALR goes to '1' and does not force any DAC to a clear
status.
R/W
CH1 alarm clear bit.
If CH1-ALR_CLR = '1', and if both the ACLRn bit in the AUTO-DAC-CLR-EN Register and
the CH1-ALR bit in the Status Register are set ('1'), then DACn is forced to a clear status.
If CH1-ALR_CLR = '0', then CH1-ALR goes to '1' and does not force any DAC to a clear
status.
R/W
CH2 alarm clear bit.
If CH2-ALR_CLR = '1', and if both the ACLRn bit in the AUTO-DAC-CLR-EN Register and
the CH2-ALR bit in the Status Register are set ('1'), then DACn is forced to a clear status.
If CH2-ALR_CLR = '0', then CH2-ALR goes to '1' and does not force any DAC to a clear
status.
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
AMC7812
www.ti.com
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
Table 26. AUTO-DAC-CLR-SOURCE Register (continued)
BIT
11
10
9
8
7
6
5
4
3
NAME
CH3-ALR-CLR
LT-Low-ALRCLR
LT-High-ALRCLR
D1-Low-ALRCLR
D1-High-ALRCLR
D2-Low-ALRCLR
D2-High-ALRCLR
D1-FAIL-CLR
D2-FAIL-CLR
DEFAULT
0
0
0
0
0
0
0
0
0
R/W
DESCRIPTION
R/W
CH3 alarm clear bit.
If CH3-ALR_CLR = '1', and if both the ACLRn bit in the AUTO-DAC-CLR-EN Register and
the CH3-ALR bit in the Status Register are set ('1'), then DACn is forced to a clear status.
If CH3-ALR_CLR = '0', then CH3-ALR goes to '1' and does not force any DAC to a clear
status.
R/W
Local temperature sensor low alarm clear bit.
If LT-Low-ALR-CLR = '1', and if both the ACLRn bit in the AUTO-DAC-CLR-EN Register
and the LT-Low-ALR bit in the Status Register are set ('1'), then DACn is forced to a clear
status.
If LT-Low-ALR-CLR = '0', then LT-Low-ALR goes to '1' and does not force any DAC to a
clear status.
R/W
Local temperature sensor high alarm clear bit.
If LT-High-ALR-CLR = '1', and if both the ACLRn bit in the AUTO-DAC-CLR-EN Register
and the LT-High-ALR bit in the Status Register are set ('1'), then DACn is forced to a clear
status.
If LT-High-ALR-CLR = '0', then LT-High-ALR goes to '1' and does not force any DAC to a
clear status.
R/W
Remote temperature sensor D1 low alarm clear bit.
If D1-Low-ALR-CLR = '1', and if both the ACLRn bit in the AUTO-DAC-CLR-EN Register
and the D1-Low-ALR bit in the Status Register are set ('1'), then DACn is forced to a clear
status.
If D1-Low-ALR-CLR = '0', then D1-Low-ALR goes to '1' and does not force any DAC to a
clear status.
R/W
Remote temperature sensor D1 high alarm clear bit.
If D1-High-ALR-CLR = '1', and if both the ACLRn bit in the AUTO-DAC-CLR-EN Register
and the D1-High-ALR bit in the Status Register are set ('1'), then DACn is forced to a clear
status.
If D1-High-ALR-CLR = '0', then D1-High-ALR goes to '1' and does not force any DAC to a
clear status.
R/W
Remote temperature sensor D2 low alarm clear bit.
If D2-Low-ALR-CLR = '1', and if both the ACLRn bit in the AUTO-DAC-CLR-EN Register
and the D2-Low-ALR bit in the Status Register are set ('1'), then DACn is forced to a clear
status.
If D2-Low-ALR-CLR = '0', then D2-Low-ALR goes to '1' and does not force any DAC to a
clear status.
R/W
Remote temperature sensor D2 high alarm clear bit.
If D2-High-ALR-CLR = '1', and if both the ACLRn bit in the AUTO-DAC-CLR-EN Register
and the D2-High-ALR bit in the Status Register are set ('1'), then DACn is forced to a clear
status.
If D2-High-ALR-CLR = '0', then D2-High-ALR goes to '1' and does not force any DAC to a
clear status.
R/W
D1 fail alarm clear bit.
If D1-FAIL-CLR = '1', and if both the ACLRn bit in the AUTO-DAC-CLR-EN Register and
the D2-FAIL-ALR bit in the Status Register are set ('1'), then DACn is forced to a clear
status.
If D1-FAIL-ALR-CLR = '0', then D1-FAIL-ALR goes to '1' and does not force any DAC to a
clear status.
R/W
D2 fail alarm clear bit.
If D2-FAIL-CLR = '1', and if both the ACLRn bit in the AUTO-DAC-CLR-EN Register and
the D2-FAIL-ALR bit in the Status Register are set ('1'), then DACn is forced to a clear
status.
If D2-FAIL-ALR-CLR = '0', then D2-FAIL-ALR goes to '1' and does not force any DAC to a
clear status.
Thermal alarm clear bit.
If THERM-ALR-CLR = '1', and if both the ACLRn bit in the AUTO-DAC-CLR-EN Register
and the THERM-ALR bit in the Status Register are set ('1'), then DACn is forced to a clear
status.
If THERM-ALR-CLR = '0', then THERM-ALR goes to '1' and does not force any DAC to a
clear status.
2
THERM-ALRCLR
1
R/W
1
—
0
R
Reserved. Writing to this bit causes no change. Reading this bit returns '0'.
0
—
0
R
Reserved. Writing to this bit causes no change. Reading this bit returns '0'.
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
73
AMC7812
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
www.ti.com
AUTO-DAC-CLR-EN REGISTER (Read/Write, Address = 54h, Default = 0000h)
MSB
BIT 15 BIT 14 BIT 13 BIT 12 BIT 11 BIT 10
0
ACLR
11
Bits[14:3]
ACLR
10
ACLR
9
ACLR
8
ACLR
7
BIT 9
BIT 8
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
LSB
BIT 0
ACLR
6
ACLR
5
ACLR
4
ACLR
3
ACLR
2
ACLR
1
ACLR
0
0
0
0
ACLRn: Auto clear DAC-n enable bit.
If ACLRn = '1', DAC-n is forced into a clear state when the alarm occurs.
If ACLRn = '0', DAC-n is not forced into a clear state when the alarm occurs (default).
NOTE
ACLRn is always ignored when an alarm occurs for a temperature greater than +150°C
(THERM-ALR = '1'). If an alarm activates for a temperature greater than +150°C, and if
the THERM-ALR-CLR bit in the AUTO-DAC-CLR-SOURCE Register is set ('1'), all DACs
are forced into a clear status. However, if THERM-ALR-CLR is cleared ('0'), the over
+150°C alarm does not force any DAC to a clear status.
SW-DAC-CLR REGISTER (Read/Write, Address = 55h, Default = 0000h)
This register uses software to force the DAC into a clear state.
MSB
BIT 15 BIT 14 BIT 13 BIT 12 BIT 11 BIT 10
0
ICLR
11
Bits[14:3]
ICLR
10
ICLR
9
ICLR
8
ICLR
7
BIT 9
BIT 8
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
LSB
BIT 0
ICLR
6
ICLR
5
ICLR
4
ICLR
3
ICLR
2
ICLR
1
ICLR
0
0
0
0
ICLRn: Software clear DACn bit.
If ICLRn = '1', DACn is forced into a clear state.
If ICLRn = '0', DACn is restored to normal operation.
HW-DAC-CLR-EN 0 REGISTER (Read/Write, Address = 56h, Default = 0000h)
This register determines which DAC is in a clear state when the DAC-CLR-0 pin goes low.
MSB
BIT
15
0
BIT 14
BIT 13
BIT 12
BIT 11
BIT 10
BIT 9
BIT 8
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
H0CLR H0CLR H0CLR H0CLR H0CLR H0CLR H0CLR H0CLR H0CLR H0CLR H0CLR H0CLR
11
10
9
8
7
6
5
4
3
2
1
0
Bits[14:3]
BIT
2
BIT
1
LSB
BIT
0
0
0
0
H0CLRn: Hardware clear DAC-n enable 1 bit.
If H0CLRn = '1', DAC-n is forced into a clear state when the DAC-CLR-0 pin goes low.
If H0CLRn = '0', pulling the DAC-CLR-0 pin low does not effect the state of DAC-n.
74
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
AMC7812
www.ti.com
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
HW-DAC-CLR-EN 1 REGISTER (Read/Write, Address = 57h, Default = 0000h)
This register determines which DAC is in a clear state when the DAC-CLR-1 pin goes low.
MSB
BIT
15
0
BIT 14
BIT 13
BIT 12
BIT 11
BIT 10
BIT 9
BIT 8
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT
2
BIT
1
LSB
BIT
0
0
0
0
H1CLR H1CLR H1CLR H1CLR H1CLR H1CLR H1CLR H1CLR H1CLR H1CLR H1CLR H1CLR
11
10
9
8
7
6
5
4
3
2
1
0
Bits[14:3]
H1CLRn: Hardware clear DAC-n enable 1 bit.
If H1CLRn = '1', DAC-n is forced into a clear state when the DAC-CLR-1 pin goes low.
If H1CLRn = '0', pulling the DAC-CLR-1 pin low does not effect the state of DAC-n.
DAC CONFIGURATION REGISTER (Read/Write, Address = 58h, Default = 0000h)
MSB
BIT 15 BIT 14 BIT 13 BIT 12 BIT 11 BIT 10
0
0
Bits[11:0]
0
0
SLDA
11
SLDA
10
BIT 9
BIT 8
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
LSB
BIT 0
SLDA
9
SLDA
8
SLDA
7
SLDA
6
SLDA
5
SLDA
4
SLDA
3
SLDA
2
SLDA
1
SLDA
0
SLDA-n: DAC synchronous load enable bit.
If SLDA-n = '1', synchronous load is enabled. When internal load DAC signal ILDAC occurs, the DAC-n Latch is loaded
with the value of the corresponding DACn-Data Register, and the output of DAC-n is updated immediately. The internal
load DAC signal ILDAC is generated by writing a '1' to the ILDAC bit in the AMC Configuration Register. In synchronous
Load, a write command to the DAC-n-Data Register updates that register only, and does not change the DAC-n output.
If SLDA-n = '0', asynchronous load is enabled. A write command to the DAC-n-Data Register immediately updates the
DAC-n Latch and the output of DAC-n. The synchronous load DAC signal (ILDAC) does not affect DACn. the default
value of SLDA-n = '0'. The AMC7812 updates the DAC Latch only if the ILDAC bit was set ('1'), thereby eliminating
unnecessary glitch. Any DAC channels that have not been accessed are not reloaded. When the DAC Latch is updated,
the corresponding output changes to the new level immediately. Note that the SLDA-n bit is ignored in auto mode (DAC-n
Mode bits do not equal '00'). In auto mode, the DAC Latch is always updated asynchronously.
NOTE
The DACs can be forced into a clear state immediately by the external DAC-CLR-n signal,
by alarm events, and by writing to the SW-DAC-CLR Register. In these cases, the SLDA-n
bit is ignored.
DAC GAIN REGISTER (Read/Write, Address = 59h, Default = 0000h)
The DACn GAIN bits specify the output range of DACn.
MSB
BIT 15 BIT 14 BIT 13 BIT 12
0
Bits[11:0]
0
0
0
BIT 11
BIT 10
BIT 9
BIT 8
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
LSB
BIT 0
DAC11
GAIN
DAC10
GAIN
DAC9
GAIN
DAC8
GAIN
DAC7
GAIN
DAC6
GAIN
DAC5
GAIN
DAC4
GAIN
DAC3
GAIN
DAC2
GAIN
DAC1
GAIN
DAC0
GAIN
DACnGAIN: DACn gain bit.
If DACn GAIN = '1', the gain = 5 and the output is 0 to 5 · VREF
If DACn GAIN = '0', the gain = 2 and the output is 0 to 2 · VREF
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
75
AMC7812
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
www.ti.com
ANALOG INPUT CHANNEL THRESHOLD REGISTERS (Read/Write, Addresses = 5Ah to 61h)
Four analog auxiliary inputs (CH0, CH1, CH2, and CH3) and three temperature sensors (LT, D1, and D2)
implement an out-of-range alarm function. Threshold-High-n and Threshold-Low-n (where n = 0, 1, 2, 3) define
the upper bound and lower bound of the nth analog input range, as shown in Table 27. This window determines
whether the nth input is out-of-range. When the input is outside the window, the corresponding CH-ALR-n bit in
the Status Register is set to '1'.
For normal operation, the value of Threshold-High-n must be greater than the value of Threshold-Low-n;
otherwise, CH-ALR-n is always set to '1' and an alarm is always indicated. Note that when the analog channel is
accessed as single-ended input, its threshold is in a straight binary format. However, when the channel is
accessed as a differential pair, its threshold is in twos complement format.
Table 27. Threshold Coding
INPUT CHANNEL
INPUT TYPE
THRESHOLD STORED IN
FORMAT
Channel 0
Single-Ended
Input-0-Threshold-High-Byte
Input-0-Threshold-Low-Byte
Straight binary
Channel 1
Single-Ended
Input-1-Threshold- High-Byte
Input-1-Threshold- Low-Byte
Straight binary
Channel 2
Single-Ended
Input-2-Threshold- High-Byte
Input-2-Threshold- Low-Byte
Straight binary
Channel 3
Single-Ended
Input-3-Threshold- High-Byte
Input-3-Threshold- Low-Byte
Straight binary
CH0+/CH1–
Differential
Input-0-Threshold- High-Byte
Input-0-Threshold- Low-Byte
Twos complement
CH2+/CH3–
Differential
Input-2-Threshold- High-Byte
Input-2-Threshold- Low-Byte
Twos complement
Input-n-High-Threshold Register (where n = 0, 1, 2, 3) (Read/Write, Default = 0FFFh)
MSB
BIT 15 BIT 14 BIT 13 BIT 12 BIT 11 BIT 10
0
0
0
0
THRH
11
THRH
10
BIT 9
BIT 8
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
LSB
BIT 0
THRH
9
THRH
8
THRH
7
THRH
6
THRH
5
THRH
4
THRH
3
THRH
2
THRH
1
THRH
0
Bits[15:12]
Reserved. These bits are '0' when read back. Writing to these bits has no effect.
Bits[11:0]
THRHn: Data bits of the upper-bound threshold of the nth analog input.
Input-n-Low-Threshold Register (where n = 0, 1, 2, 3) (Read/Write, Default = 0000h)
MSB
BIT 15 BIT 14 BIT 13 BIT 12 BIT 11 BIT 10
0
0
0
0
THRL
11
THRL
10
BIT 9
BIT 8
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
LSB
BIT 0
THRL
9
THRL
8
THRL
7
THRL
6
THRL
5
THRL
4
THRL
3
THRL
2
THRL
1
THRL
0
Bits[15:12]
Reserved. These bits are '0' when read back. Writing to these bits has no effect.
Bits[11:0]
THRLn: Data bits of the lower-bound threshold of the nth analog input.
76
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
AMC7812
www.ti.com
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
TEMPERATURE THRESHOLD REGISTERS
LT-High-Threshold Register (Read/Write, Address = 62h, Default = 07FFh, +255.875°C)
MSB
BIT 15 BIT 14 BIT 13 BIT 12 BIT 11 BIT 10
0
0
0
0
THRH
11
THRH
10
BIT 9
BIT 8
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
LSB
BIT 0
THRH
9
THRH
8
THRH
7
THRH
6
THRH
5
THRH
4
THRH
3
THRH
2
THRH
1
THRH
0
Bits [15:12] = ‘0' when read back. Writing these bits causes no change
LT-Low-Threshold Register (Read/Write, Address = 63h, Default = 0800h, –256°C)
MSB
BIT 15 BIT 14 BIT 13 BIT 12 BIT 11 BIT 10
0
0
0
0
THRL
11
THRL
10
BIT 9
BIT 8
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
LSB
BIT 0
THRL
9
THRL
8
THRL
7
THRL
6
THRL
5
THRL
4
THRL
3
THRL
2
THRL
1
THRL
0
Bits [15:12] = Reserved. Writing to these bits causes no change. Reading these bits returns '0'.
D1-High-Threshold Register (Read/Write, Address = 64h, Default = 07FFh, +255.875°C)
MSB
BIT 15 BIT 14 BIT 13 BIT 12 BIT 11 BIT 10
0
0
0
0
THRH
11
THRH
10
BIT 9
BIT 8
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
LSB
BIT 0
THRH
9
THRH
8
THRH
7
THRH
6
THRH
5
THRH
4
THRH
3
THRH
2
THRH
1
THRH
0
Bits [15:12] = ‘0' when read back. Writing these bits causes no change
D1-Low-Threshold Register (Read/Write, Address = 65h, Default = 0800h, –256°C)
MSB
BIT 15 BIT 14 BIT 13 BIT 12 BIT 11 BIT 10
0
0
0
0
THRL
11
THRL
10
BIT 9
BIT 8
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
LSB
BIT 0
THRL
9
THRL
8
THRL
7
THRL
6
THRL
5
THRL
4
THRL
3
THRL
2
THRL
1
THRL
0
Bits [15:12] = ‘0' when read back. Writing these bits causes no change
D2-High-Threshold Register (Read/Write, Address = 66h, Default = 07FFh, +255.875°C)
MSB
BIT 15 BIT 14 BIT 13 BIT 12 BIT 11 BIT 10
0
0
0
0
THRH
11
THRH
10
BIT 9
BIT 8
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
LSB
BIT 0
THRH
9
THRH
8
THRH
7
THRH
6
THRH
5
THRH
4
THRH
3
THRH
2
THRH
1
THRH
0
Bits [15:12] = ‘0' when read back. Writing these bits causes no change
D2-Low-Threshold Register (Read/Write, Address = 67h, Default = 0800h, –256°C)
MSB
BIT 15 BIT 14 BIT 13 BIT 12 BIT 11 BIT 10
0
0
0
0
THRL
11
THRL
10
BIT 9
BIT 8
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
LSB
BIT 0
THRL
9
THRL
8
THRL
7
THRL
6
THRL
5
THRL
4
THRL
3
THRL
2
THRL
1
THRL
0
Bits [15:12] = ‘0' when read back. Writing these bits causes no change
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
77
AMC7812
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
www.ti.com
HYSTERESIS REGISTERS
The hysteresis registers define the hysteresis in the alarm detection of an individual alarm.
Hysteresis Register 0 (Read/Write, Address = 68h, Default = 0810h, 8 LSB)
This register contains the hysteresis values for CH0 and CH1.
MSB
BIT 15 BIT 14 BIT 13 BIT 12 BIT 11 BIT 10
BIT 9
BIT 8
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
CH0CH0CH0CH0CH0CH0CH0CH1CH1CH1CH1CH1CH1CH1HYS-6 HYS-5 HYS-4 HYS-3 HYS-2 HYS-1 HYS-0 HYS-6 HYS-5 HYS-4 HYS-3 HYS-2 HYS-1 HYS-0
0
Bits[14:8]
CH0-HYS-n: Hysteresis of CH0, 1 LSB per step.
Bits[7:1]
CH1-HYS-n: Hysteresis of CH1, 1 LSB per step.
LSB
BIT 0
0
Hysteresis Register 1 (Read/Write, Address = 69h, Default = 0810h, 8 LSB)
This register contains the hysteresis values for CH2 and CH3.
MSB
BIT 15 BIT 14 BIT 13 BIT 12 BIT 11 BIT 10
BIT 9
BIT 8
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
CH2CH2CH2CH2CH2CH2CH2CH3CH3CH3CH3CH3CH3CH3HYS-6 HYS-5 HYS-4 HYS-3 HYS-2 HYS-1 HYS-0 HYS-6 HYS-5 HYS-4 HYS-3 HYS-2 HYS-1 HYS-0
0
Bits[14:8]
CH2-HYS-n: Hysteresis of CH2, 1 LSB per step.
Bits[7:1]
CH3-HYS-n: Hysteresis of CH3, 1 LSB per step.
LSB
BIT 0
0
Hysteresis Register 2 (Read/Write, Address = 6Ah, Default = 2108h, 8°C)
This register contains the hysteresis values for D2, D1, and LT. The range is 0°C to +32°C.
MSB
BIT 15 BIT 14 BIT 13 BIT 12 BIT 11 BIT 10
BIT 9
BIT 8
BIT 7
BIT 6
BIT 5
BIT 4
BIT 2
BIT 1
LSB
BIT 0
D2D2D2D2D2D1D1D1D1D1LTLTLTLTLTHYS-7 HYS-6 HYS-5 HYS-4 HYS-3 HYS-7 HYS-6 HYS-5 HYS-4 HYS-3 HYS-7 HYS-6 HYS-5 HYS-4 HYS-3
0
Bits[14:10]
D2-HYS-n: Hysteresis of D2, 1°C per step. Note that bits D2-HYS-[2:0] are always '0'.
Bits[9:5]
D1-HYS-n: Hysteresis of D1, 1°C per step. Note that bits D1-HYS-[2:0] are always '0'.
Bits[4:0]
LT-HYS-n: Hysteresis of LT, 1°C per step. Note that bits LT-HYS-[2:0] are always '0'.
78
BIT 3
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
AMC7812
www.ti.com
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
POWER-DOWN REGISTER (Read/Write, Address = 6Bh, Default = 0000h)
After power-on or reset, all bits in the Power-Down Register are cleared to '0', and all the components controlled
by this register are either powered-down or off. The Power-Down Register allows the host to manage the
AMC7812 power dissipation. When not required, the ADC, the reference buffer amplifier, and any of the DACs
can be put into an inactive low-power mode to reduce current drain from the supply. The bits in the Power-Down
Register control this power-down function. Set the respective bit to '1' to activate the corresponding function.
MSB
BIT 15 BIT 14 BIT 13 BIT 12 BIT 11 BIT 10
0
PADC
PREF
PDAC
0
PDAC
1
PDAC
2
BIT 9
BIT 8
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
PDAC
3
PDAC
4
PDAC
5
PDAC
6
PDAC
7
PDAC
8
PDAC
9
PDAC
10
PDAC
11
LSB
BIT 0
Bit 14
PADC: Power-down mode control bit.
If PADC = '1', the ADC is in normal operating mode.
If PADC = '0', the ADC is inactive in low-power mode.
Bit 13
PREF: Internal reference in power-down mode control bit.
If PREF = '1', the reference buffer amplifier is powered on.
If PREF = '0', the reference buffer amplifier is inactive in low-power mode.
Bits[12:1]
PDACn: DACn power-down control bit.
If PDACn = '1', DACn is in normal operating mode.
If PDACn = '0', DACn is inactive in low-power mode and its output buffer amplifier is in a Hi-Z state. The output pin of
DACn is internally switched from the buffer output to the analog ground through an internal resistor.
0
Device ID Register (Read-Only, Address = 6Ch, Default = 1220h)
Model and revision information.
Software Reset Register (Read/Write, Address = 7Ch, Default = NA)
The Software Reset Register resets all registers to default values, except for the DAC Data Register, DAC Latch,
and DAC Clear Register. The software reset is similar to a hardware reset, which resets all registers including
the DAC Data Register, DAC Latch, and DAC Clear Register. After a software reset, make sure that the DAC
Data Register, DAC latch, and DAC Clear Register are set to the desired values before the DAC is powered on.
SPI Mode
In SPI Mode, writing 6600h to this register forces the device reset.
I2C Mode
Writing to this register (with any data) forces the device to perform a software reset. Reading this register returns
an undefined value that must be ignored. Note that this register is 8-bit, instead of 16-bit. Both reading from and
writing to this register are single-byte operations. Writing data to the Software Reset Register in I2C Mode is
shown in the following steps:
1. The master device asserts a start condition.
2. The master then sends the 7-bit AMC7812 slave address followed by a zero for the direction bit, indicating a
write operation.
3. The AMC7812 asserts an acknowledge signal on SDA.
4. The master sends register address 7Ch.
5. The AMC7812 asserts an acknowledge signal on SDA.
6. The master sends a data byte.
7. The AMC7812 asserts an acknowledge signal on SDA.
8. The master asserts a stop condition to end the transaction.
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
79
AMC7812
SBAS513C – JANUARY 2011 – REVISED MARCH 2012
www.ti.com
REVISION HISTORY
NOTE: Page numbers for previous revisions may differ from page numbers in the current version.
Changes from Revision B (November 2011) to Revision C
Page
•
Changed Features Bullet From: Small Packages: 9mm x 9mm QFN-64 To: Small Packages: 9mm x 9mm QFN-64,
and 10mm x 10mm HTQFP-64 ............................................................................................................................................. 1
•
Added HTQFP-64 package option to the Description .......................................................................................................... 1
•
Added HTQFP-64 package to the PACKAGE/ORDERING INFORMATION table .............................................................. 2
•
Added PAP (HTQFP) to the Thermal Information table ....................................................................................................... 2
•
Added the HTQFP-64 Pin Configuration .............................................................................................................................. 8
•
Added text "QFN Package" to Figure 75 and Figure 76 ..................................................................................................... 28
•
Added Figure 77 and Figure 78 .......................................................................................................................................... 28
•
η-Factor Range Table, Changed From: 0000 0020 To: 0000 0010 ................................................................................... 37
•
η-Factor Range Table, Changed From 1111 0000 To: 1000 0000 .................................................................................... 37
Changes from Revision A (March 2011) to Revision B
Page
•
Added text to Desciption section .......................................................................................................................................... 1
•
Added Reset Delay parameter to Electrical Charactieristics ................................................................................................ 6
•
Added Convert Pulse Width parameter to Electrical Characteristics .................................................................................... 6
•
Added Reset Pulse Width parameter to Electrical Characteristics ....................................................................................... 6
•
Changed recommended compensation capacitor from 470nF to 4.7µF .............................................................................. 9
•
Changed recommended compensation capacitor value from 470nF to 4.7µF to reflect bench characterization
conditions ............................................................................................................................................................................ 39
•
Changed text in first paragraph of Clear DACs section ...................................................................................................... 43
•
Clarified voltage condition for hardware reset .................................................................................................................... 48
•
Added description of software reset function ...................................................................................................................... 48
•
Added voltage condition for initiation of POR ..................................................................................................................... 48
•
Added Power Supply Sequence section. ............................................................................................................................ 49
Changes from Original (January 2011) to Revision A
Page
•
Changed Load Current to include separate source/sink test conditions; updated from one row with typical value of
±7mA at 200mV .................................................................................................................................................................... 3
•
Added Direct Mode test condition to Conversion Rate parameter ....................................................................................... 4
•
Deleted test condition from Absolute Input Voltage parameter ............................................................................................ 4
•
Added note to clarify Power Dissipation conditions .............................................................................................................. 6
•
Added missing figure number for Figure 6 ......................................................................................................................... 15
•
Updated X axis range in Figure 34 to include –12mA ........................................................................................................ 19
•
Changed Y axis label to "Offset Error" in Figure 61 (typo) ................................................................................................. 25
•
Added Figure 67 ................................................................................................................................................................. 26
•
Updated Programmable Conversion Rate section ............................................................................................................. 33
•
Added Nap Enabled column to Table 1 .............................................................................................................................. 33
•
Changed latch position in Figure 93 ................................................................................................................................... 43
•
Changed Table 9 to show SDI/SDO relationship ............................................................................................................... 56
•
Changed bit 12 entries of Table 23 from don't care to 0 .................................................................................................... 71
•
Changed bit 9 entries of Table 24 from don't care to 0 ...................................................................................................... 71
80
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): AMC7812
PACKAGE OPTION ADDENDUM
www.ti.com
30-May-2012
PACKAGING INFORMATION
Orderable Device
Status
(1)
Package Type Package
Drawing
Pins
Package Qty
Eco Plan
(2)
Lead/
Ball Finish
MSL Peak Temp
(3)
AMC7812SPAP
ACTIVE
HTQFP
PAP
64
160
Green (RoHS
& no Sb/Br)
CU NIPDAU Level-3-260C-168 HR
AMC7812SPAPR
ACTIVE
HTQFP
PAP
64
1000
Green (RoHS
& no Sb/Br)
CU NIPDAU Level-3-260C-168 HR
AMC7812SRGCR
ACTIVE
VQFN
RGC
64
2000
Green (RoHS
& no Sb/Br)
CU NIPDAU Level-3-260C-168 HR
AMC7812SRGCT
ACTIVE
VQFN
RGC
64
250
Green (RoHS
& no Sb/Br)
CU NIPDAU Level-3-260C-168 HR
Samples
(Requires Login)
(1)
The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
(2)
Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availability
information and additional product content details.
TBD: The Pb-Free/Green conversion plan has not been defined.
Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that
lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes.
Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used between
the die and leadframe. The component is otherwise considered Pb-Free (RoHS compatible) as defined above.
Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight
in homogeneous material)
(3)
MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature.
Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information
provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and
continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals.
TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release.
In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis.
Addendum-Page 1
PACKAGE MATERIALS INFORMATION
www.ti.com
14-Jul-2012
TAPE AND REEL INFORMATION
*All dimensions are nominal
Device
Package Package Pins
Type Drawing
SPQ
Reel
Reel
A0
Diameter Width (mm)
(mm) W1 (mm)
B0
(mm)
K0
(mm)
P1
(mm)
W
Pin1
(mm) Quadrant
AMC7812SPAPR
HTQFP
PAP
64
1000
330.0
24.4
13.0
13.0
1.5
16.0
24.0
Q2
AMC7812SRGCR
VQFN
RGC
64
2000
330.0
16.4
9.3
9.3
1.5
12.0
16.0
Q2
AMC7812SRGCT
VQFN
RGC
64
250
180.0
16.4
9.3
9.3
1.5
12.0
16.0
Q2
Pack Materials-Page 1
PACKAGE MATERIALS INFORMATION
www.ti.com
14-Jul-2012
*All dimensions are nominal
Device
Package Type
Package Drawing
Pins
SPQ
Length (mm)
Width (mm)
Height (mm)
AMC7812SPAPR
HTQFP
PAP
64
1000
367.0
367.0
55.0
AMC7812SRGCR
VQFN
RGC
64
2000
367.0
367.0
38.0
AMC7812SRGCT
VQFN
RGC
64
250
210.0
185.0
35.0
Pack Materials-Page 2
IMPORTANT NOTICE
Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, enhancements, improvements and other
changes to its semiconductor products and services per JESD46C and to discontinue any product or service per JESD48B. Buyers should
obtain the latest relevant information before placing orders and should verify that such information is current and complete. All
semiconductor products (also referred to herein as “components”) are sold subject to TI’s terms and conditions of sale supplied at the time
of order acknowledgment.
TI warrants performance of its components to the specifications applicable at the time of sale, in accordance with the warranty in TI’s terms
and conditions of sale of semiconductor products. Testing and other quality control techniques are used to the extent TI deems necessary
to support this warranty. Except where mandated by applicable law, testing of all parameters of each component is not necessarily
performed.
TI assumes no liability for applications assistance or the design of Buyers’ products. Buyers are responsible for their products and
applications using TI components. To minimize the risks associated with Buyers’ products and applications, Buyers should provide
adequate design and operating safeguards.
TI does not warrant or represent that any license, either express or implied, is granted under any patent right, copyright, mask work right, or
other intellectual property right relating to any combination, machine, or process in which TI components or services are used. Information
published by TI regarding third-party products or services does not constitute a license to use such products or services or a warranty or
endorsement thereof. Use of such information may require a license from a third party under the patents or other intellectual property of the
third party, or a license from TI under the patents or other intellectual property of TI.
Reproduction of significant portions of TI information in TI data books or data sheets is permissible only if reproduction is without alteration
and is accompanied by all associated warranties, conditions, limitations, and notices. TI is not responsible or liable for such altered
documentation. Information of third parties may be subject to additional restrictions.
Resale of TI components or services with statements different from or beyond the parameters stated by TI for that component or service
voids all express and any implied warranties for the associated TI component or service and is an unfair and deceptive business practice.
TI is not responsible or liable for any such statements.
Buyer acknowledges and agrees that it is solely responsible for compliance with all legal, regulatory and safety-related requirements
concerning its products, and any use of TI components in its applications, notwithstanding any applications-related information or support
that may be provided by TI. Buyer represents and agrees that it has all the necessary expertise to create and implement safeguards which
anticipate dangerous consequences of failures, monitor failures and their consequences, lessen the likelihood of failures that might cause
harm and take appropriate remedial actions. Buyer will fully indemnify TI and its representatives against any damages arising out of the use
of any TI components in safety-critical applications.
In some cases, TI components may be promoted specifically to facilitate safety-related applications. With such components, TI’s goal is to
help enable customers to design and create their own end-product solutions that meet applicable functional safety standards and
requirements. Nonetheless, such components are subject to these terms.
No TI components are authorized for use in FDA Class III (or similar life-critical medical equipment) unless authorized officers of the parties
have executed a special agreement specifically governing such use.
Only those TI components which TI has specifically designated as military grade or “enhanced plastic” are designed and intended for use in
military/aerospace applications or environments. Buyer acknowledges and agrees that any military or aerospace use of TI components
which have not been so designated is solely at the Buyer's risk, and that Buyer is solely responsible for compliance with all legal and
regulatory requirements in connection with such use.
TI has specifically designated certain components which meet ISO/TS16949 requirements, mainly for automotive use. Components which
have not been so designated are neither designed nor intended for automotive use; and TI will not be responsible for any failure of such
components to meet such requirements.
Products
Applications
Audio
www.ti.com/audio
Automotive and Transportation www.ti.com/automotive
Amplifiers
amplifier.ti.com
Communications and Telecom www.ti.com/communications
Data Converters
dataconverter.ti.com
Computers and Peripherals
www.ti.com/computers
DLP® Products
www.dlp.com
Consumer Electronics
www.ti.com/consumer-apps
DSP
dsp.ti.com
Energy and Lighting
www.ti.com/energy
Clocks and Timers
www.ti.com/clocks
Industrial
www.ti.com/industrial
Interface
interface.ti.com
Medical
www.ti.com/medical
Logic
logic.ti.com
Security
www.ti.com/security
Power Mgmt
power.ti.com
Space, Avionics and Defense
www.ti.com/space-avionics-defense
Microcontrollers
microcontroller.ti.com
Video and Imaging
www.ti.com/video
RFID
www.ti-rfid.com
OMAP Mobile Processors
www.ti.com/omap
TI E2E Community
e2e.ti.com
Wireless Connectivity
www.ti.com/wirelessconnectivity
Mailing Address: Texas Instruments, Post Office Box 655303, Dallas, Texas 75265
Copyright © 2012, Texas Instruments Incorporated