TI1 DAC7678 12-bit, octal-channel, ultra-low glitch, voltage output, two-wire interface digital-to-analog converter with 2.5v internal reference Datasheet

DAC7678
www.ti.com
SBAS493A – FEBRUARY 2010 – REVISED AUGUST 2010
12-Bit, Octal-Channel, Ultra-Low Glitch, Voltage Output, Two-Wire Interface
Digital-to-Analog Converter with 2.5V Internal Reference
Check for Samples: DAC7678
FEATURES
APPLICATIONS
•
•
•
•
•
•
•
1
23
•
•
•
•
•
•
•
•
Relative Accuracy:
– 1 LSB INL
Glitch Energy: 0.15nV-s
Internal Reference:
– 2.5V Reference Voltage (disabled by
default)
– ±5mV Initial Accuracy (max)
– 5ppm/°C Temperature Drift (typ)
– 25ppm/°C Temperature Drift (max)
– 20mA Sink/Source Capability
Power-On Reset to Zero Scale or Midscale
– Devices in the TSSOP Package Reset to
Zero Scale
– Devices in the QFN Package Reset to Zero
Scale or Midscale
Ultra-Low Power Operation: 0.13mA/Channel
at 5V (without internal reference current)
Wide Power-Supply Range: +2.7V to +5.5V
2-Wire Serial Interface ( I2C™ compatible)
On-Chip Output Buffer Amplifier with
Rail-to-Rail Operation
Temperature Range: –40°C to +125°C
AVDD
VREFIN/VREFOUT
DAC7678
SCL
2.5V
Reference
Input Control Logic
Data Buffer H
DAC Register H
12-Bit DAC
VOUTH
Data Buffer G
DAC Register G
12-Bit DAC
VOUTG
Data Buffer F
DAC Register F
12-Bit DAC
VOUTF
Data Buffer E
DAC Register E
12-Bit DAC
VOUTE
Data Buffer D
DAC Register D
12-Bit DAC
VOUTD
Data Buffer C
DAC Register C
12-Bit DAC
VOUTC
Data Buffer B
DAC Register B
12-Bit DAC
VOUTB
Data Buffer A
DAC Register A
12-Bit DAC
VOUTA
Buffer Control
Register Control
Power-Down
Control Logic
SDA
Control Logic
ADDR0
ADDR1
LDAC
RSTSEL
CLR
Portable Instrumentation
Closed-Loop Servo-Control
Process Control
Data Acquisition Systems
Programmable Attenuation
PC Peripherals
DESCRIPTION
The DAC7678 is a low-power, voltage-output, octal
channel, 12-bit digital-to-analog converter (DAC). The
DAC7678 includes a 2.5V internal reference (disabled
by default), giving a full-scale output voltage range of
5V. The internal reference has an initial accuracy of
±5mV and can source up to 20mA at the
VREFIN/VREFOUT pin. The device is monotonic,
provides very good linearity, and minimizes undesired
code-to-code transient voltages (glitch).
The DAC7678 uses a versatile, 2-wire serial interface
that is I2C-compatible and operates at clock rates of
up to 3.4MHz. Multiple devices can share the same
bus.
The DAC7678 incorporates a power-on-reset circuit
that ensures the DAC output powers up to either
zero-scale or mid-scale until a valid code is written to
the device. These devices contain a power-down
feature, accessed over the serial interface that
reduces the current consumption of the device to
typically 0.42mA at 5V. Power consumption (including
internal reference) is typically 3.56mW at 3V,
reducing to 0.68mW in power-down mode. The low
power consumption, internal reference, and small
footprint make this device ideal for portable,
battery-operated equipment. The DAC7678 is drop-in
and
functionally
compatible
with
DAC5578,
DAC6578, and DAC7578. All devices are available in
a 4x4 QFN-24 package and a TSSOP-16 package.
8-BIT
10-BIT
12-BIT
Pin- and Function-Compatible
(w/internal reference)
RELATED DEVICES
—
—
DAC7678
Pin- and Function-Compatible
DAC5578
DAC6578
DAC7578
GND
1
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.
I C is a trademark of NXP Semiconductors.
All other trademarks are the property of their respective owners.
2
2
3
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 © 2010, Texas Instruments Incorporated
DAC7678
SBAS493A – FEBRUARY 2010 – REVISED AUGUST 2010
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)
MAXIMUM
REFERENCE DRIFT
(ppm/°C)
DAC7678
±1
±0.25
25
(1)
PACKAGELEAD
PACKAGE
DESIGNATOR
TSSOP-16
PW
QFN-24
RGE
SPECIFIED
TEMPERATURE
RANGE
PACKAGE
MARKING
–40°C to +125°C
DAC7678
For the most current package and ordering information see the Package Option Addendum at the end of this document, or see the TI
web site at www.ti.com.
ABSOLUTE MAXIMUM RATINGS (1)
Over operating free-air temperature range, unless otherwise noted.
DAC7678
UNIT
–0.3 to +6
V
Digital input voltage to GND
–0.3 to +AVDD + 0.3
V
VOUT to GND
–0.3 to +AVDD + 0.3
V
VREFIN/VREFOUT to GND
AVDD to GND
–0.3 to +AVDD + 0.3
V
Operating temperature range
–40 to +125
°C
Storage temperature range
–65 to +150
°C
+150
°C
(TJ max – TA)/qJA
W
Junction temperature range (TJ max)
Power dissipation
(1)
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
THERMAL METRIC (1)
DAC7678
PW (16 PINS)
RGE (24 PINS)
qJA
Junction-to-ambient thermal resistance
111.9
33.7
qJCtop
Junction-to-case (top) thermal resistance
33.3
16.9
qJB
Junction-to-board thermal resistance
52.4
7.4
yJT
Junction-to-top characterization parameter
2
0.5
yJB
Junction-to-board characterization parameter
51.2
7.1
qJCbot
Junction-to-case (bottom) thermal resistance
n/a
1.7
(1)
2
UNITS
°C/W
For more information about traditional and new thermal metrics, see the IC Package Thermal Metrics application report, SPRA953.
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SBAS493A – FEBRUARY 2010 – REVISED AUGUST 2010
ELECTRICAL CHARACTERISTICS
At AVDD = 2.7V to 5.5V, External Reference Used, and over –40°C to +125°C, unless otherwise noted.
PARAMETER
TEST CONDITIONS
DAC7678
MIN
TYP
MAX
UNIT
STATIC PERFORMANCE (1)
Resolution
12
Bits
Relative accuracy
Measured by the line passing through codes 30 and 4050
±0.3
±1
LSB
Differential nonlinearity
12-bit monotonic
±0.1
±0.25
LSB
Offset error
Extrapolated from two-point line (2), unloaded
0.5
±4
Offset error drift
Full-scale error
DAC register loaded with all '1's
±0.03
Full-scale error drift
Zero-code error
mV/°C
±0.2
% of FSR
2
DAC register loaded with all '0's
1
Zero-code error drift
Gain error
mV
3
mV/°C
4
mV
2
Extrapolated from two-point line (2), unloaded
±0.01
Gain temperature coefficient
mV/°C
±0.15
% of FSR
ppm of
FSR/°C
±1
OUTPUT CHARACTERISTICS (3)
Output voltage range
Output voltage settling time
0
DACs unloaded, 1/4 scale to 3/4 scale
RL = 1MΩ, CL = 470 pF
Slew rate
Capacitive load stability
RL = ∞
AVDD
V
7
ms
12
ms
0.75
V/ms
470
pF
RL = 2kΩ
1000
pF
Code change glitch impulse
1LSB change around major carry
0.15
nV-s
Digital feedthrough
SCL toggling
1.5
nV-s
Power-on glitch
RL = ∞
Channel-to-channel dc crosstalk
3
mV
Full-scale swing on adjacent channel
0.1
LSB
DC output impedance
At midscale input
4.5
Ω
Short-circuit current
DAC outputs shorted to GND
25
mA
Power-up time (including settling time)
Coming out of power-down mode, AVDD = 5V
50
ms
DAC output noise density
TA = +25°C, at zero-code input, fOUT = 1kHz
20
nV/√Hz
DAC output noise
TA = +25°C, at midscale input, 0.1Hz to 10Hz (external
reference used)
3
mVPP
AC PERFORMANCE (3)
(1)
(2)
(3)
Linearity calculated using a reduced code range; output unloaded.
12-bit: 30 and 4050
Specified by design or characterization; not production tested.
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DAC7678
SBAS493A – FEBRUARY 2010 – REVISED AUGUST 2010
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ELECTRICAL CHARACTERISTICS (continued)
At AVDD = 2.7V to 5.5V, External Reference Used, and over –40°C to +125°C, unless otherwise noted.
PARAMETER
DAC7678
TEST CONDITIONS
MIN
TYP
MAX
UNIT
INTERNAL REFERENCE
Output voltage
TA = +25°C
2.495
2.5
2.505
Initial accuracy
TA = +25°C
–5
±0.1
5
mV
5
25
ppm/°C
Output voltage temperature drift (4)
Output voltage noise
TA = +25°C, f = 0.1Hz to 10Hz
15
Output voltage noise density
(high-frequency noise)
TA = +25°C, f = 1kHz, CL = 0mF
250
TA = +25°C, f = 1MHz, CL = 0mF
50
Load regulation (5)
Output current load capability
Thermal hysteresis
(5)
Internal reference current consumption
External reference current
500
mV/mA
200
mV/mA
±20
mA
80
mV/V
TA = +25°C, time = 0 to 2160 hours
100
ppm
First cycle
200
ppm
50
ppm
AVDD = 5.5V
420
mA
AVDD = 3.6V
400
mA
60
mA
Additional cycles
External VREF = 2.5V (when internal reference is disabled), all
eight channels active
VREFIN/VREFOUT pin reference input range
Reference input impedance
nV/√Hz
Sinking, TA = +25°C
TA = +25°C
Long-term stability/drift (aging) (5)
mVPP
Sourcing, TA = +25°C
(4)
Line regulation
V
0
Reference disabled
AVDD
42
V
kΩ
LOGIC INPUTS (4)
Input current
±1
mA
VINL
Logic input LOW voltage
2.7V ≤ AVDD ≤ 5.5V
GND–0.3
0.3×AVDD
VINH
Logic input HIGH voltage
2.7V ≤ AVDD ≤ 5.5V
0.7×AVDD
AVDD+0.3
V
3
pF
Pin capacitance
1.5
V
POWER REQUIREMENTS
AVDD
IDD
2.7
(6)
5.5
V
Normal mode, internal
reference switched off
AVDD = 3.6V to 5.5V, VINH = AVDD and VINL = GND
1.02
1.4
mA
AVDD = 2.7V to 3.6V, VINH = AVDD and VINL = GND
0.86
1.3
mA
Normal mode, internal
reference switched on
AVDD = 3.6V to 5.5V, VINH = AVDD and VINL = GND
1.49
2.2
mA
AVDD = 2.7V to 3.6V, VINH = AVDD and VINL = GND
1.32
2
mA
AVDD = 3.6V to 5.5V, VINH = AVDD and VINL = GND
0.42
6
mA
AVDD = 2.7V to 3.6V, VINH = AVDD and VINL = GND
0.25
4.7
mA
Normal mode, internal
reference switched off
AVDD = 3.6V to 5.5V, VINH = AVDD and VINL = GND
3.67
7.7
mW
AVDD = 2.7V to 3.6V, VINH = AVDD and VINL = GND
2.32
4.68
mW
Normal mode, internal
reference switched on
AVDD = 3.6V to 5.5V, VINH = AVDD and VINL = GND
5.36
12.1
mW
AVDD = 2.7V to 3.6V, VINH = AVDD and VINL = GND
3.56
7.2
mW
AVDD = 3.6V to 5.5V, VINH = AVDD and VINL = GND
1.51
33
mW
AVDD = 2.7V to 3.6V, VINH = AVDD and VINL = GND
0.68
16.92
mW
+125
°C
All power-down modes
Power
dissipation (6)
All power-down modes
TEMPERATURE RANGE
Specified performance
(4)
(5)
(6)
4
–40
Specified by design or characterization; not production tested.
Explained in more detail in the Application Information section of this data sheet.
Input code = midscale, no load.
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SBAS493A – FEBRUARY 2010 – REVISED AUGUST 2010
PIN CONFIGURATIONS
PW PACKAGE
TSSOP-16
(TOP VIEW)
TWOC
SDA
22
SCL
NC
23
21
20
19
LDAC
1
16
SCL
NC
LDAC
RGE PACKAGE
QFN-24
(TOP VIEW)
ADDR0
2
15
SDA
24
AVDD
3
14
GND
NC
1
18
VOUTA
4
13
VOUTB
AVDD
2
17
GND
VOUTA
3
16
VOUTB
VOUTC
4
15
VOUTD
VOUTE
5
14
VOUTF
VOUTG
6
13
VOUTH
VOUTE
6
11
VOUTF
VOUTG
7
10
VOUTH
VREFIN/VREFOUT
8
9
CLR
DAC7678
(Thermal pad)
NC
7
(1)
1
8
9
10
11
12
CLR
VOUTD
ADDR1
12
ADDR0
5
RSTSEL
VOUTC
VREFIN/VREFOUT
DAC7678
NC
It is recommended to connect the thermal
pad to GND for better thermal dissipation.
PIN DESCRIPTIONS
16-PIN
24-PIN
NAME
1
22
LDAC
DESCRIPTION
2
11
ADDR0
3
2
AVDD
Power-supply input, 2.7V to 5.5V
4
3
VOUTA
Analog output voltage from DAC A
5
4
VOUTC
Analog output voltage from DAC C
6
5
VOUTE
Analog output voltage from DAC E
7
6
VOUTG
Analog output voltage from DAC G
8
8
VREFIN/
VREFOUT
Load DACs.
Three-state address input 0
Positive reference input or reference output of 2.5V, if internal reference used.
9
12
CLR
10
13
VOUTH
Asynchronous clear input
Analog output voltage from DAC H
11
14
VOUTF
Analog output voltage from DAC F
12
15
VOUTD
Analog output voltage from DAC D
13
16
VOUTB
Analog output voltage from DAC B
14
17
GND
Ground reference point for all circuitry on the device
15
19
SDA
Serial data input. Data are clocked into or out of the input register. This pin is a bidirectional,
open-drain data line that should be connected to the supply voltage with an external pull-up resistor.
16
20
SCL
Serial clock input. Data can be transferred at rates up to 3.4MHz. Schmitt-trigger logic input.
—
1
NC
Not internally connected.
—
7
NC
Not internally connected.
—
9
RSTSEL
Reset select pin. RSTSEL high resets device to mid-scale; RSTSEL low resets device to zero-scale.
—
10
ADDR1
Three-state address input 1
—
18
NC
—
21
TWOC
—
23
NC
Not internally connected.
—
24
NC
Not internally connected.
Not internally connected.
Twos complement select. If the TWOC pin is pulled high, the DAC registers use twos complement
format; if TWOC is pulled low, the DAC registers use straight binary format.
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DAC7678
SBAS493A – FEBRUARY 2010 – REVISED AUGUST 2010
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TIMING DIAGRAM
tLOW
Low Byte Ack Cycle
tR
tHD:STA
tF
SCL
tHD:STA
tHIGH
tSU:STA
tSU:STO
tSU:DAT
tHD:DAT
SDA
tBUF
P
S
S
P
t1
LDAC1
t3
t2
LDAC2
t4
CLR
(1)
Asynchronous LDAC update mode. For more information and details, see the LDAC Functionality section
(2)
Synchronous LDAC update mode. For more information and details, see the LDAC Functionality section
Figure 1. Serial Write Operation
TIMING REQUIREMENTS
At AVDD = 2.7 V to 5.5 V and –40°C to +125°C range (unless otherwise noted).
STANDARD
MODE
PARAMETER
MIN MAX
SCL frequency, fSCL
FAST
MODE
MIN
0.1
Bus free time between STOP and START conditions, tBUF
Hold time after repeated start, tHDSTA
HIGH SPEED
MODE
MAX
MIN
0.4
4.7
1.3
UNIT
MAX
3.4
MHz
µs
4
0.6
0.16
µs
4.7
0.6
0.16
µs
STOP condition setup time, tSUSTO
4
0.6
0.16
µs
Data hold time, tHDDAT
0
0
0
ns
Repeated Start setup time, tSUSTA
Data setup time, tSUDAT
250
100
10
ns
SCL clock LOW period, tLOW
4700
1300
160
ns
SCL clock HIGH period, tHIGH
4000
600
60
ns
Clock/Data fall time, tF
300
300
160
Clock/Data rise time, tR
1000
300
160
LDAC pulse width LOW time, t1
40
10
ns
ns
1.2
µs
SCL falling edge to LDAC falling edge for asynchronous LDAC update, t2
20
5
0.6
µs
LDAC falling edge to SCL falling edge for synchronous LDAC update, t3
360
90
10.5
µs
40
10
1.2
µs
CLR pulse width LOW time, t4
6
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TYPICAL CHARACTERISTICS: INTERNAL REFERENCE
At TA = 25°C, unless otherwise noted
INTERNAL REFERENCE VOLTAGE
vs TEMPERATURE
LONG-TERM STABILITY DRIFT
2.505
22 Devices Shown
150
2.502
100
2.501
50
2.500
2.499
0
-50
2.498
-100
2.497
-150
2.496
-200
2.495
-40
-25
-10
5
19 Devices Shown
200
2.503
Drift - ppm
Reference Voltage - V
2.504
250
20
35
50
65
T - Temperature - °C
80
95
110
-250
125
0
240
480
720
960
1200 1440
t - Time - Hours
1680
1920
Figure 2.
Figure 3.
INTERNAL REFERENCE VOLTAGE
vs SUPPLY VOLTAGE
INTERNAL REFERENCE VOLTAGE
vs LOAD CURRENT
2.505
2160
2.515
2.504
2.510
TA = 125°C
Reference Voltage - V
Reference Voltage - V
2.503
2.502
TA = 25°C
2.501
2.500
TA = -40°C
2.499
2.498
TA = 125°C
TA = 25°C
2.505
TA = -40°C
2.500
2.495
2.497
2.496
2.495
2.7
3.1
3.5
4.3
3.9
Supply Voltage - V
4.7
5.1
5.5
2.490
-20
-15
-10
-5
0
5
Load Current - mA
10
Figure 4.
Figure 5.
INTERNAL REFERENCE NOISE DENSITY
vs FREQUENCY
INTERNAL REFERENCE NOISE
0.1 Hz to 10 Hz
15
20
350
Reference Unbuffered
CREF = 0 mF
300
Vnoise - 5 mV/div
Voltage Noise - nV/ÖHz
250
200
150
- 15 mV
Peak-to-peak
100
50
0
10
100
1000
f - Frequency - Hz
10000
100000
Figure 6.
t - Time - 2s/div
Figure 7.
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TYPICAL CHARACTERISTICS: DAC at AVDD = 5.5 V
At TA = 25°C, external reference used, DAC output not loaded, and all DAC codes in straight binary data format, unless
otherwise noted
LINEARITY ERROR
vs DIGITAL INPUT CODE (All 8 channels)
DIFFERENTIAL LINEARITY ERROR
vs DIGITAL INPUT CODE (All 8 channels)
0.25
1.0
All Eight Channels Shown,
AVDD = 5.5 V,
Internal Reference = 2.5 V
0.8
0.6
0.15
0.10
DNL - Error - LSB
INL - Error - LSB
0.4
0.2
0.0
-0.2
-0.4
-0.8
CHB
CHF
CHD
CHH
0.00
-0.05
-0.15
0
1.00
512
1024
1536
2048
2560
Digital Input Code
3072
3584
DNL CHA
DNL CHB
DNL CHC
DNL CHD
-0.20
-1.0
-0.25
4096
0
512
1536
2048
2560
Digital Input Code
3072
3584
Figure 9.
LINEARITY ERROR
vs DIGITAL INPUT CODE (–40°C)
DIFFERENTIAL LINEARITY ERROR
vs DIGITAL INPUT CODE (–40°C)
4096
0.25
0.60
AVDD = 5.5 V,
0.20 Internal Reference = 2.5 V,
Typical Channel Shown
0.15
0.40
0.10
DNL - Error - LSB
0.20
0.00
-0.20
0.05
0.00
-0.05
-0.40
-0.10
-0.60
-0.15
-0.80
-0.20
-1.00
0
512
1024
1536
2048
2560
Digital Input Code
3072
3584
-0.25
4096
0
512
1024
1536
2048
2560
Digital Input Code
3072
3584
Figure 10.
Figure 11.
LINEARITY ERROR
vs DIGITAL INPUT CODE (+25°C)
DIFFERENTIAL LINEARITY ERROR
vs DIGITAL INPUT CODE(+25°C)
4096
0.25
1.00
AVDD = 5.5 V,
Internal Reference = 2.5 V,
Typical Channel Shown
0.80
0.60
0.20
0.15
AVDD = 5.5 V,
Internal Reference = 2.5 V,
Typical Channel Shown
0.10
DNL - Error - LSB
0.40
0.20
0.00
-0.20
0.05
0.00
-0.05
-0.40
-0.10
-0.60
-0.15
-0.80
-0.20
-1.00
0
512
1024
1536
2048
2560
Digital Input Code
3072
3584
4096
-0.25
0
Figure 12.
8
1024
DNL CHE
DNL CHF
DNLCHG
DNLCHH
Figure 8.
AVDD = 5.5 V,
Internal Reference = 2.5 V,
Typical Channel Shown
0.80
INL - Error - LSB
0.05
-0.10
CHA
CHE
CHC
CHG
-0.6
INL - Error - LSB
All Eight Channels Shown
AVDD = 5.5 V,
Internal Reference = 2.5 V
0.20
512
1024
1536
2048
2560
Digital Input Code
3072
3584
4096
Figure 13.
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SBAS493A – FEBRUARY 2010 – REVISED AUGUST 2010
TYPICAL CHARACTERISTICS: DAC at AVDD = 5.5 V (continued)
At TA = 25°C, external reference used, DAC output not loaded, and all DAC codes in straight binary data format, unless
otherwise noted
LINEARITY ERROR
vs DIGITAL INPUT CODE (+125°C)
DIFFERENTIAL LINEARITY ERROR
vs DIGITAL INPUT CODE (+125°C)
0.25
1.00
AVDD = 5.5 V,
0.80 Internal Reference = 2.5 V,
Typical Channel Shown
0.60
0.15
0.10
DNL - Error - LSB
INL - Error - LSB
0.40
0.20
0.00
-0.20
0.05
0.00
-0.05
-0.40
-0.10
-0.60
-0.15
-0.80
-0.20
-1.00
0
512
1024
1536
2048
2560
Digital Input Code
3072
3584
-0.25
4096
1536
2048
2560
Digital Input Code
3072
3584
DIFFERENTIAL LINEARITY ERROR
vs TEMPERATURE
4096
0.25
AVDD = 5.5 V,
Internal Reference = 2.5 V
AVDD = 5.5 V,
Internal Reference = 2.5 V
0.20
0.15
DNL - Error - LSB
INL MAX
0.20
0.00
INL MIN
-0.20
0.10
DNL MAX
0.05
0.00
-0.10
-0.60
-0.15
-0.80
-0.20
-25
-10
5
20
35
50
65
T - Temperature -°C
80
95
110
125
DNL MIN
-0.05
-0.40
1.40
1024
LINEARITY ERROR
vs TEMPERATURE
0.40
-1.00
-40
512
Figure 15.
0.60
INL - Error - LSB
0
Figure 14.
1.00
0.80
AVDD = 5.5 V,
Internal Reference = 2.5 V,
Typical Channel Shown
0.20
-0.25
-40
-25
5
-10
20
35
50
65
T - Temperature -°C
80
Figure 16.
Figure 17.
POWER SUPPLY CURRENT
vs TEMPERATURE
OFFSET ERROR
vs TEMPERATURE
95
110
125
4
AVDD = 5.5 V,
External Reference = 5 V
3
AVDD = 5.5 V,
Internal Reference = 2.5 V
2
1.20
Offset Error - mV
Power-Supply Current - mA
1.30
1.10
1.00
1
0
-1
-2
0.90
0.80
-40
-3
-25
-10
5
20
35
50
65
T - Temperature -°C
80
95
110
125
-4
-40
-25
Figure 18.
-10
5
20
35
50
65
T - Temperature -°C
80
Ch A
Ch C
Ch E
Ch G
Ch B
Ch D
Ch F
Ch H
95
110
125
Figure 19.
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TYPICAL CHARACTERISTICS: DAC at AVDD = 5.5 V (continued)
At TA = 25°C, external reference used, DAC output not loaded, and all DAC codes in straight binary data format, unless
otherwise noted
POWER SUPPLY CURRENT
vs TEMPERATURE
FULL-SCALE ERROR
vs TEMPERATURE
0.20
2.20
AVDD = 5.5 V,
Internal Reference = 2.5 V
0.15
2.00
1.90
1.80
1.70
1.60
1.50
0.05
0.00
-0.05
-0.10
DAC A
DAC C
DAC E
DAC G
-0.15
1.40
1.30
-40
-25
-10
5
20
35
50
65
T - Temperature -°C
80
95
110
-0.20
-40
125
-25
-10
5
20
35
50
65
T - Temperature -°C
80
Figure 20.
Figure 21.
POWER-DOWN CURRENT
vs TEMPERATURE
GAIN ERROR
vs TEMPERATURE
6.00
95
110
125
AVDD = 5.5 V,
Internal Reference = 2.5 V
5.00
0.10
4.50
Gain Error - %FSR
4.00
3.50
3.00
2.50
2.00
0.05
0.00
-0.05
1.50
1.00
DAC A
DAC C
DAC E
DAC G
-0.10
0.50
0.00
-40
-25
-10
5
20
35
50
65
T - Temperature -°C
80
95
110
-0.15
-40
125
-25
-10
5
20
35
50
65
T - Temperature -°C
80
Figure 22.
Figure 23.
SOURCE CURRENT
AT POSITIVE RAIL
SINK CURRENT
AT NEGATIVE RAIL
5.00
DAC B
DAC D
DAC F
DAC H
95
110
125
0.60
Channel C
0.50
AVDD = 5.5 V,
Internal Reference Enabled,
DAC Loaded with 000h
Channel C
Output Voltage - V
4.95
Output Voltage - V
DAC B
DAC D
DAC F
DAC H
0.15
AVDD = 5.5 V,
Internal Reference = 2.5 V
5.50
Power Supply Current - mA
AVDD = 5.5 V,
Internal Reference = 2.5 V
0.10
Full Scale Error - %FSR
Power Supply Current - mA
2.10
4.90
0.40
0.30
0.20
4.85
AVDD = 5.5 V,
Internal Reference Enabled,
DAC Loaded with FFFh
0.10
4.80
0
2
4
6
8
10
0.00
0
ISOURCE - mA
Figure 24.
10
1
2
3
4
5
6
Isink - mA
7
8
9
10
Figure 25.
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SBAS493A – FEBRUARY 2010 – REVISED AUGUST 2010
TYPICAL CHARACTERISTICS: DAC at AVDD = 5.5 V (continued)
At TA = 25°C, external reference used, DAC output not loaded, and all DAC codes in straight binary data format, unless
otherwise noted
SOURCE CURRENT
AT POSITIVE RAIL
SINK CURRENT
AT NEGATIVE RAIL
5.00
0.60
Channel D
0.50
AVDD = 5.5 V,
Internal Reference Enabled,
DAC Loaded with 000h
Channel D
Output Voltage - V
Output Voltage - V
4.95
4.90
0.40
0.30
0.20
4.85
AVDD = 5.5 V,
Internal Reference Enabled,
DAC Loaded with FFFh
4.80
0
1
2
3
4
5
6
ISOURCE - mA
7
8
9
0.10
0.00
0
10
1
2
3
4
5
6
ISINK - mA
7
Figure 26.
Figure 27.
SOURCE CURRENT
AT POSITIVE RAIL
SINK CURRENT
AT NEGATIVE RAIL
5.00
9
10
9
10
0.60
Channel H
0.50
AVDD = 5.5 V,
Internal Reference Enabled,
DAC Loaded with 000h
Channel H
Output Voltage - V
4.95
Output Voltage - V
8
4.90
0.40
0.30
0.20
4.85
AVDD = 5.5 V,
Internal Reference Enabled,
DAC Loaded with FFFh
4.80
0
1
2
3
4
5
6
ISOURCE - mA
7
8
9
0.10
0.00
0
10
1
2
3
4
5
6
ISINK - mA
7
8
Figure 28.
Figure 29.
POWER SUPPLY CURRENT
vs DIGITAL INPUT CODE
POWER SUPPLY CURRENT
vs DIGITAL INPUT CODE
2.20
1.40
2.10
1.20
Power Supply Current - mA
Power Supply Current - mA
2.00
1.90
1.80
1.70
1.60
1.50
1.40
AVDD = 5.5 V,
Internal Reference Enabled,
Code Loaded to all Eight DAC Channels
1.30
1.20
1.10
0
512
1024
1536
2048
2560
Digital Input Code
3072
3584
1.00
0.80
0.60
0.40
AVDD = 5.5 V,
External Reference = 5 V,
Internal Reference Disabled,
Code Loaded to all Eight DAC Channels
0.20
4096
0.00
0
Figure 30.
512
1024
1536
2048
2560
Digital Input Code
3072
3584
4096
Figure 31.
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TYPICAL CHARACTERISTICS: DAC at AVDD = 5.5 V (continued)
At TA = 25°C, external reference used, DAC output not loaded, and all DAC codes in straight binary data format, unless
otherwise noted
POWER SUPPLY CURRENT
vs POWER SUPPLY VOLTAGE
POWER SUPPLY CURRENT
vs POWER SUPPLY VOLTAGE
2.20
1.40
AVDD = 2.7 V to 5.5 V,
Internal Reference Enabled
AVDD = 2.7 V to 5.5 V,
Internal Reference Disabled
1.30
Power Supply Current - mA
Power Supply Current - mA
2.00
1.80
1.60
1.40
1.20
1.10
1.00
0.90
0.80
1.20
0.70
1.00
2.7
3.1
3.5
4.3
4.7
3.9
AVDD - Supply Voltage - V
5.1
0.60
2.7
5.5
3.9
4.3
4.7
AVDD - Supply Voltage - V
Figure 33.
POWER DOWN CURRENT
vs POWER SUPPLY VOLTAGE
POWER-SUPPLY CURRENT
HISTOGRAM
5.1
5.5
16
AVDD = 2.7 V to 5.5 V
0.40
14
0.35
% of Population
0.25
0.20
0.15
10
8
6
4
0.10
1.70
1.66
1.68
1.60
1.62
1.64
1.56
1.58
5.5
1.52
1.54
5.1
1.48
1.50
4.7
1.44
1.46
4.3
1.38
3.9
AVDD - Supply Voltage - V
1.40
1.42
3.5
1.34
1.36
0
3.1
1.30
2
1.32
0.00
2.7
AVDD = 5.5 V,
Internal Reference = 2.5 V
12
0.30
0.05
IDD - Supply Current - mA
Figure 34.
12
3.5
Figure 32.
0.45
Power Supply Current - mA
3.1
Figure 35.
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SBAS493A – FEBRUARY 2010 – REVISED AUGUST 2010
TYPICAL CHARACTERISTICS: DAC at AVDD = 5.5 V (continued)
At TA = 25°C, external reference used, DAC output not loaded, and all DAC codes in straight binary data format, unless
otherwise noted
POWER-SUPPLY CURRENT
HISTOGRAM
14
AVDD = 5.5 V,
12 External Reference = 5 V
% of Population
10
8
6
4
2
0.90
0.91
0.92
0.93
0.94
0.95
0.96
0.97
0.98
0.99
1.00
1.01
1.02
1.03
1.04
1.05
1.06
1.07
1.08
1.09
1.10
1.11
1.12
1.13
1.14
1.15
0
IDD - Supply Current - mA
Figure 36.
FULL-SCALE SETTLING TIME:
5V RISING EDGE
FULL-SCALE SETTLING TIME:
5V FALLING EDGE
AVDD = 5.5 V,
From Code FFFh to 000h
Internal Reference Enabled
Zoomed Rising Edge
100 mV/div
Zoomed Falling Edge
100 mV/div
Falling Edge
2 V/div
Rising Edge
2 V/div
Trigger Pulse
5 V/div
AVDD = 5.5 V,
From Code 000h to FFFh,
Internal Reference Enabled
Trigger Pulse
5 V/div
t - Time - 5 ms/div
t - Time - 5 ms/div
Figure 37.
Figure 38.
HALF-SCALE SETTLING TIME:
5V RISING EDGE
HALF-SCALE SETTLING TIME:
5V FALLING EDGE
AVDD = 5.5 V,
From Code 400h to C00h
Internal Reference Enabled
AVDD = 5.5 V,
From Code C00h to 400h
Internal Reference Enabled
Zoomed Rising Edge
100 mV/div
Zoomed Falling Edge
100 mV/div
Falling Edge
2 V/div
Rising Edge
2 V/div
Trigger Pulse
5 V/div
Trigger Pulse
5 V/div
t - Time - 5 ms/div
t - Time - 5 ms/div
Figure 39.
Figure 40.
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TYPICAL CHARACTERISTICS: DAC at AVDD = 5.5 V (continued)
At TA = 25°C, external reference used, DAC output not loaded, and all DAC codes in straight binary data format, unless
otherwise noted
CLOCK FEEDTHROUGH
400 kHz, MIDSCALE
POWER-ON GLITCH
RESET TO ZERO SCALE
AVDD = 5.5 V,
Clock Feedthrough Impulse ~1.5 nV-s
Internal Reference Enabled
AVDD = 5.5 V,
DAC Unloaded,
DAC at Zero Scale
VOUT - 2 mV/div
~2 mVPP
VOUT - 5 mV/div
SCL - 5 V/div
AVDD - 2 V/div
t - Time - 10 ms/div
t - Time - 1 ms/div
Figure 41.
Figure 42.
POWER-ON GLITCH
RESET-TO-MID SCALE
POWER-OFF GLITCH
AVDD = 5.5 V,
DAC Unloaded,
DAC at Zero Scale
AVDD = 5.5 V,
DAC Unloaded,
DAC at Zero Scale
VOUT - 2 V/div
VOUT - 1 mV/div
AVDD - 2 V/div
AVDD - 2 V/div
t - Time - 20 ms/div
t - Time - 10 ms/div
Figure 43.
Figure 44.
GLITCH ENERGY:
5V 1LSB STEP, RISING EDGE
GLITCH ENERGY:
5V 1LSB STEP, FALLING EDGE
AVDD = 5.5 V,
From Code 800h to 801h
VOUT - 500 mV/div
AVDD = 5.5 V,
From Code 801h to 800h
LDAC Clock
Feed-Through
VOUT - 500 mV/div
LDAC - Trigger Pulse
5 V/div
LDAC Clock
Feed-Through
LDAC - Trigger Pulse
5 V/div
t - Time - 2 ms/div
t - Time - 2 ms/div
Figure 45.
14
Figure 46.
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SBAS493A – FEBRUARY 2010 – REVISED AUGUST 2010
TYPICAL CHARACTERISTICS: DAC at AVDD = 5.5 V (continued)
At TA = 25°C, external reference used, DAC output not loaded, and all DAC codes in straight binary data format, unless
otherwise noted
DAC OUTPUT NOISE DENSITY vs FREQUENCY
INTERNAL REFERENCE ENABLED
DAC OUTPUT NOISE DENSITY vs FREQUENCY
INTERNAL REFERENCE DISABLED
800
300
AVDD = 5.5 V,
DAC Output Unloaded,
Internal Reference = 2.5 V
700
250
Voltage Noise - nV/Ö Hz
Full Scale
600
Voltage Noise - nV/ÖHz
AVDD = 5.5 V,
DAC Output Unloaded,
External Reference = 5 V
500
400
Mid Scale
300
200
200
150
Full Scale
100
Mid Scale
50
100
0
20
Zero Scale
Zero Scale
100
1000
10000
f - Frequency - Hz
0
20
100000
Figure 47.
100
1000
f - Frequency - Hz
10000
100000
Figure 48.
VOUT - 1 mV/div
DAC OUTPUT NOISE
0.1 Hz to 10 Hz
~3 mVPP
t - Time - 2 s/div
Figure 49.
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TYPICAL CHARACTERISTICS: DAC AT AVDD = 3.6 V
At TA = 25°C, external reference used, DAC output not loaded, and all DAC codes in straight binary data format, unless
otherwise noted
POWER SUPPLY CURRENT
vs TEMPERATURE
POWER SUPPLY CURRENT
vs DIGITAL INPUT CODE
1.30
1.30
1.20
1.10
Power Supply Current - mA
Power Supply Current - mA
1.20
AVDD = 3.6 V,
External Reference = 3.3 V
1.10
1.00
0.90
0.80
1.00
0.90
0.80
0.70
0.60
0.50
0.40
AVDD = 3.6 V,
External Reference = 3.3 V,
Internal Reference Disabled,
Code Loaded to all Eight DAC Channels
0.30
0.20
0.10
0.70
-40
-25
-10
5
20
35
50
65
T - Temperature -°C
80
95
110
0.00
125
0
512
1024
Figure 50.
1536
2048
2560
Digital Input Code
3072
3584
4096
Figure 51.
POWER SUPPLY CURRENT
HISTOGRAM
14
AVDD = 3.6 V,
External Reference = 3.3 V
12
% of Population
10
8
6
4
0
0.765
0.775
0.785
0.795
0.805
0.815
0.825
0.835
0.845
0.855
0.865
0.875
0.885
0.895
0.905
0.915
0.925
0.935
0.945
0.955
0.965
0.975
2
IDD - Supply Current - mA
Figure 52.
16
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SBAS493A – FEBRUARY 2010 – REVISED AUGUST 2010
TYPICAL CHARACTERISTICS: DAC AT AVDD = 2.7 V
At TA = 25°C, external reference used, DAC output not loaded, and all DAC codes in straight binary data format, unless
otherwise noted
LINEARITY ERROR
vs DIGITAL INPUT CODE (All 8 Channels)
DIFFERENTIAL LINEARITY ERROR
vs DIGITAL INPUT CODE (All 8 Channels)
1.00
0.25
AVDD = 2.7 V,
External Reference = 2.5 V
0.80
0.15
0.60
0.10
DNL - Error - LSB
INL - Error - LSB
0.40
0.20
0.00
-0.20
0.05
0.00
-0.05
-0.10
-0.40
-0.60
CHA
CHB
CHC
CHD
-0.80
-0.15
CHE
CHF
CHG
CHH
DNL CHA
DNL CHB
DNL CHC
DNL CHD
-0.20
DNL CHE
DNL CHF
DNL CHG
DNL CHH
-0.25
512
1024
1536
2048
2560
Digital Input Code
3072
3584
0
4096
512
1024
1536
2048
2560
Digital Input Code
3072
3584
Figure 53.
Figure 54.
LINEARITY ERROR
vs DIGITAL INPUT CODE (-40°C)
DIFFERENTIAL LINEARITY ERROR
vs DIGITAL INPUT CODE (-40°C)
1.00
0.25
AVDD = 2.7 V,
0.80 External Reference = 2.5 V
AVDD = 2.7 V,
0.20 External Reference = 2.5 V
0.60
0.15
0.40
0.10
DNL - Error - LSB
INL - Error - LSB
-1.00
0
0.20
0.00
-0.20
4096
0.05
0.00
-0.05
-0.40
-0.10
-0.60
-0.15
-0.80
-0.20
-0.25
-1.00
0
512
1024
1536
2048
2560
Digital Input Code
3072
3584
0
4096
1536
2048
2560
Digital Input Code
3072
3584
LINEARITY ERROR
vs DIGITAL INPUT CODE (+25°C)
DIFFERENTIAL LINEARITY ERROR
vs DIGITAL INPUT CODE (+25°C)
0.25
AVDD = 2.7 V,
0.80 External Reference = 2.5 V
0.20
0.60
0.15
0.40
0.10
0.20
0.00
-0.20
-0.05
-0.60
-0.15
-0.80
-0.20
1024
1536
2048
2560
Digital Input Code
3072
3584
4096
AVDD = 2.7 V,
External Reference = 2.5 V
0.00
-0.10
-1.00
4096
0.05
-0.40
512
1024
Figure 56.
1.00
0
512
Figure 55.
DNL - Error - LSB
INL - Error - LSB
AVDD = 2.7 V,
External Reference = 2.5 V
0.20
-0.25
0
Figure 57.
512
1024
1536
2048
2560
Digital Input Code
3072
3584
4096
Figure 58.
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TYPICAL CHARACTERISTICS: DAC AT AVDD = 2.7 V (continued)
At TA = 25°C, external reference used, DAC output not loaded, and all DAC codes in straight binary data format, unless
otherwise noted
LINEARITY ERROR
vs DIGITAL INPUT CODE (+125°C)
DIFFERENTIAL LINEARITY ERROR
vs DIGITAL INPUT CODE (+125°C)
0.25
AVDD = 2.7 V,
0.80 External Reference = 2.5 V
0.20
0.60
0.15
0.40
0.10
DNL - Error - LSB
INL - Error - LSB
1.00
0.20
0.00
-0.20
0.05
0.00
-0.05
-0.40
-0.10
-0.60
-0.15
-0.80
-0.20
-1.00
-0.25
0
512
1024
1536
2048
2560
Digital Input Code
3072
3584
4096
0
0.80
3584
4096
0.25
AVDD = 2.7 V,
External Reference = 2.5 V
AVDD = 2.7 V,
External Reference = 2.5 V
0.20
0.15
DNL - Error - LSB
0.20
0.00
INL MIN
-0.20
0.05
0.00
-0.10
-0.60
-0.15
-0.80
-0.20
-10
5
20
35
50
65
T - Temperature -°C
80
95
110
125
DNL MIN
-0.05
-0.40
-25
DNL MAX
0.10
-0.25
-40
-25
-10
5
20
35
50
65
T - Temperature -°C
80
Figure 61.
Figure 62.
POWER-SUPPLY CURRENT
vs TEMPERATURE
OFFSET ERROR
vs TEMPERATURE
1.30
4
AVDD = 2.7 V,
1.20 External Reference = 2.5 V
3
95
110
125
AVDD = 2.7 V,
External Reference = 2.5 V
2
1.10
Offset Error - mV
INL - Error - LSB
3072
DIFFERENTIAL LINEARITY ERROR
vs TEMPERATURE
0.40
1.00
0.90
0.80
1
0
-1
-2
0.70
DAC A
DAC C
DAC E
DAC G
-3
-25
-10
5
20
35
50
65
T - Temperature -°C
80
95
110
125
-4
-40
-25
Figure 63.
18
1536
2048
2560
Digital Input Code
LINEARITY ERROR
vs TEMPERATURE
INL MAX
0.60
-40
1024
Figure 60.
0.60
-1.00
-40
512
Figure 59.
1.00
Power-Supply Current - mA
AVDD = 2.7 V,
External Reference = 2.5 V
-10
5
20
35
50
65
T - Temperature -°C
80
DAC B
DAC D
DAC F
DAC H
95
110
125
Figure 64.
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TYPICAL CHARACTERISTICS: DAC AT AVDD = 2.7 V (continued)
At TA = 25°C, external reference used, DAC output not loaded, and all DAC codes in straight binary data format, unless
otherwise noted
POWER-DOWN CURRENT
vs TEMPERATURE
FULL-SCALE ERROR
vs TEMPERATURE
0.20
AVDD = 2.7 V,
4.20
External Reference = 2.5 V
3.90
3.60
AVDD = 2.7 V,
External Reference = 2.5 V
0.15
0.10
Full-Scale Error - %FSR
Power Supply Current - mA
4.70
4.50
3.30
3.00
2.70
2.40
2.10
1.80
1.50
1.20
0.05
0.00
-0.05
-0.10
DAC A
DAC C
DAC E
DAC G
0.90
0.60
0.30
0.00
-40
-0.15
-25
-10
5
20
35
50
65
T - Temperature -°C
80
95
110
-0.20
-40
125
-25
-10
5
20
35
50
65
T - Temperature -°C
Figure 65.
80
95
DAC B
DAC D
DAC F
DAC H
110
125
9
10
Figure 66.
GAIN ERROR
vs TEMPERATURE
0.15
AVDD = 2.7 V,
External Reference = 2.5 V
Gain Error - %FSR
0.10
0.05
0.00
-0.05
DAC A
DAC C
DAC E
DAC G
-0.10
-0.15
-40
-25
-10
5
20
35
50
65
T - Temperature -°C
80
95
DAC B
DAC D
DAC F
DAC H
110
125
Figure 67.
SOURCE CURRENT
AT POSITIVE RAIL
SINK CURRENT
AT NEGATIVE RAIL
2.500
0.60
AVDD = 2.7 V,
External Reference = 2.5 V,
DAC Loaded with FFFh
2.495
Channel A
2.490
AVDD = 2.7 V,
External Reference = 2.5 V,
DAC Loaded with 000h
0.50
Channel A
Output Voltage - V
Output Voltage - V
2.485
2.480
2.475
2.470
2.465
0.40
0.30
0.20
2.460
2.455
0.10
2.450
2.445
0
1
2
3
4
5
6
ISOURCE - mA
7
8
9
10
0.00
0
Figure 68.
1
2
3
4
5
6
ISINK - mA
7
8
Figure 69.
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TYPICAL CHARACTERISTICS: DAC AT AVDD = 2.7 V (continued)
At TA = 25°C, external reference used, DAC output not loaded, and all DAC codes in straight binary data format, unless
otherwise noted
SOURCE CURRENT
AT POSITIVE RAIL
SINK CURRENT
AT NEGATIVE RAIL
2.500
0.60
AVDD = 2.7 V,
External Reference = 2.5 V,
DAC Loaded with FFFh
2.495
Channel B
AVDD = 2.7 V,
External Reference = 2.5 V,
DAC Loaded with 000h
0.50
2.490
Channel B
Output Voltage - V
Output Voltage - V
2.485
2.480
2.475
2.470
0.40
0.30
0.20
2.465
2.460
0.10
2.455
2.450
0
0.00
1
2
3
4
5
6
ISOURCE - mA
7
8
9
0
10
1
2
3
4
5
6
ISINK - mA
7
Figure 70.
Figure 71.
SOURCE CURRENT
AT POSITIVE RAIL
SINK CURRENT
AT NEGATIVE RAIL
2.500
8
9
10
9
10
0.60
AVDD = 2.7 V,
External Reference = 2.5 V,
DAC Loaded with FFFh
2.495
Channel G
AVDD = 2.7 V,
External Reference = 2.5 V,
DAC Loaded with 000h
0.50
2.490
Channel G
Output Voltage - V
Output Voltage - V
2.485
2.480
2.475
2.470
2.465
2.460
0.40
0.30
0.20
0.10
2.455
2.450
0
0.00
1
2
3
4
5
6
ISOURCE - mA
7
8
9
10
0
Figure 72.
20
1
2
3
4
5
6
ISINK - mA
7
8
Figure 73.
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TYPICAL CHARACTERISTICS: DAC AT AVDD = 2.7 V (continued)
At TA = 25°C, external reference used, DAC output not loaded, and all DAC codes in straight binary data format, unless
otherwise noted
POWER SUPPLY CURRENT
vs DIGITAL INPUT CODE
POWER SUPPLY CURRENT
HISTOGRAM
1.30
1.10
1.00
14
0.90
% of Population
Power Supply Current - mA
18
AVDD = 2.7 V,
16 External Reference = 2.5 V
AVDD = 2.7 V,
External Reference = 2.5 V,
Internal Reference Disabled,
Code Loaded to all Eight DAC Channels
1.20
0.80
0.70
0.60
0.50
0.40
0.30
12
10
8
6
4
0.20
2
0.90
0.88
0.89
0.85
0.86
0.87
0.83
0.84
4096
0.81
0.82
3584
0.79
0.80
3072
0.77
0.78
1536
2048
2560
Digital Input Code
0.74
1024
0.75
0.76
512
0.72
0.73
0
0.70
0
0.00
0.71
0.10
IDD - Supply Current - mA
Figure 74.
Figure 75.
FULL-SCALE SETTLING TIME:
2.7V RISING EDGE
FULL-SCALE SETTLING TIME:
2.7V FALLING EDGE
AVDD = 2.7 V,
From Code FFFh to 000h
External Reference = 2.5 V
AVDD = 2.7 V,
From Code 000h to FFFh
External Reference = 2.5 V
Zoomed Rising Edge
100 mV/div
Zoomed Falling Edge
100 mV/div
Falling Edge
2 V/div
Rising Edge
2 V/div
Trigger Pulse
5 V/div
Trigger Pulse
5 V/div
t - Time - 5 ms/div
t - Time - 5 ms/div
Figure 76.
Figure 77.
HALF-SCALE SETTLING TIME:
2.7V RISING EDGE
HALF-SCALE SETTLING TIME:
2.7V FALLING EDGE
AVDD = 2.7 V,
From Code 400h to C00h
External Reference = 2.5 V
AVDD = 2.7 V,
From Code C00h to 400h
External Reference = 2.5 V
Zoomed Falling Edge
100 mV/div
Zoomed Rising Edge
100 mV/div
Falling Edge
2 V/div
Rising Edge
2 V/div
Trigger Pulse
5 V/div
Trigger Pulse
5 V/div
t - Time - 5 ms/div
t - Time - 5 ms/div
Figure 78.
Figure 79.
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TYPICAL CHARACTERISTICS: DAC AT AVDD = 2.7 V (continued)
At TA = 25°C, external reference used, DAC output not loaded, and all DAC codes in straight binary data format, unless
otherwise noted
CLOCK FEEDTHROUGH
400 kHz, MIDSCALE
POWER-ON GLITCH
RESET TO ZERO SCALE
AVDD = 2.7 V,
Clock Feedthrough Impulse ~ 0.5n V-s
External Reference = 2.5 V
VOUT - 2 mV/div
~ 1.8 mVPP
AVDD = 2.7 V,
External Reference = 2.5 V,
DAC = Zero Scale,
DACs unloaded
VOUT - 5 mV/div
AVDD - 2 V/div
SCL - 5 V/div
t - Time - 10 ms/div
t - Time - 1 ms/div
Figure 80.
Figure 81.
POWER-ON GLITCH
RESET TO MIDSCALE
POWER-OFF GLITCH
AVDD = 2.7 V,
External Reference = 2.5 V,
DAC = Mid Scale,
DACs Unloaded
VOUT - 2 mV/div
AVDD = 2.7 V,
DAC = Zero Scale
VOUT - 1 mV/div
AVDD - 2 V/div
AVDD - 2 V/div
t - Time - 10 ms/div
t - Time - 20 ms/div
Figure 82.
Figure 83.
GLITCH ENERGY:
2.7V 1LSB STEP, RISING EDGE
GLITCH ENERGY:
2.7V 1LSB STEP, FALLING EDGE
AVDD = 2.7 V,
From Code 800h to 801h
External Reference = 2.5 V
VOUT - 500 mV/div
LDAC Clock
Feed-Through
LDAC Clock
Feed-Through
LDAC - Trigger Pulse
5 V/div
LDAC - Trigger Pulse
5 V/div
t - Time - 2 ms/div
t - Time - 2 ms/div
Figure 84.
22
AVDD = 2.7 V,
From Code 801h to 800h
External Reference = 2.5 V
VOUT - 500 mV/div
Figure 85.
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THEORY OF OPERATION
DIGITAL-TO-ANALOG CONVERTER (DAC)
The DAC7678 architecture consists of eight string
DACs each followed by an output buffer amplifier.
The DAC7678 also includes an internal 2.5V
reference with a maximum 25ppm/°C temperature
drift performance, offering a 5V, full-scale output
voltage. Figure 86 shows a principal block diagram of
the DAC architecture.
VREFIN/VREFOUT
150kW
will be un-shorted if external reference is used. Thus
the overall gain will be one and allows the user to
provide an external reference value of 0 to AVDD. If
internal reference is used RDIVIDER is shorted and the
overall gain will be two.
VREF
RDIVIDER
VREF
2
150kW
178kW
DAC
Register
R
VOUTX
REF(+)
Resistor String
REF(-)
To Output Amplifier
(2x Gain)
R
Figure 86. Device Architecture
For the TSSOP package, the input coding to the
DAC7678 is straight binary. For the QFN package,
the TWOC pin controls the code format.
When using the internal reference, the ideal output
voltage is given by Equation 1:
DIN
VOUT =
´ 2 ´ VREFOUT
4096
(1)
R
When using an external reference, the ideal output
voltage is given by Equation 2:
DIN
VOUT =
´ VREFIN
4096
(2)
Where:
DIN = decimal equivalent of the binary code that
is loaded to the DAC register. It can range from 0
to 4095.
VREFOUT = internal reference voltage of 2.5V (typ),
supplied at the VREFIN/VREFOUT pin.
VREFIN = external reference voltage of 0V to 5V
(typ), supplied at the VREFIN/VREFOUT pin.
RESISTOR STRING
The resistor string circuitry is shown in Figure 87. It is
a string of resistors, each of value R. The code
loaded into the DAC register determines at which
node on the string the voltage is tapped off to be fed
into the output amplifier by closing one of the
switches connecting the string to the amplifier. It is
monotonic because it is a string of resistors. RDIVIDER
R
Figure 87. Resistor String
OUTPUT AMPLIFIER
The output buffer amplifier is capable of generating
rail-to-rail voltages on its output, giving a maximum
output range of 0V to AVDD. It is capable of driving a
load of 2kΩ in parallel with 1000pF to GND. The
source and sink capabilities of the output amplifier
can be seen in the Typical Characteristics. The
typical slew rate is 0.75V/ms, with a typical full-scale
settling time of 7ms with the output unloaded.
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INTERNAL REFERENCE
using an external reference. The internal reference
can be powered up and powered down using a serial
command that requires a 32-bit write sequence,
which consists of 8 bit Address Byte plus 24 bit serial
command as shown in Table 1. During the time that
the internal reference is disabled, the DAC functions
normally using an external reference. However, when
switching to the external reference the internal gain is
dynamically switched to one. Therefore appropriate
value of external reference should be used per the
desired output voltage. At this point, the internal
reference is disconnected from the VREFIN/VREFOUT pin
(3-state output). Do not attempt to drive the
VREFIN/VREFOUT pin externally and internally at the
same time indefinitely. There are two modes that
allow communication with the internal reference:
Regular/Static and Flexible. In Flexible mode DB14
needs to be set to '1' as shown in Table 17.
The DAC7678 includes a 2.5V internal reference that
is disabled by default. The internal reference is
externally available at the VREFIN/VREFOUT pin. A
minimum 100nF capacitor is recommended between
the reference output and GND for noise filtering. The
internal reference of the DAC7678 is a
bipolar-transistor based precision bandgap voltage
reference. Figure 88 shows the basic bandgap
topology. Transistors Q1 and Q2 are biased such that
the current density of Q1 is greater than that of Q2.
The difference of the two base-emitter voltages (VBE1
– VBE2) has a positive temperature coefficient and is
forced across resistor R1. This voltage is gained up
and added to the base-emitter voltage of Q2, which
has a negative temperature coefficient. The resulting
output voltage is virtually independent of temperature.
The short-circuit current is limited by design to
approximately 100mA.
Regular/Static Mode (see Table 1 and Table 2)
Enabling Internal Reference:
VREF
To enable the internal reference, write the 24-bit
serial command shown in Table 1 after properly
addressing the device. When performing a power
cycle to reset the device, the internal reference is
switched off (default mode). In the default mode, the
internal reference is powered down until a valid write
sequence is applied to power up the internal
reference. Setting DB4 to '1' turns on the internal
reference.If the internal reference is powered up, it
automatically powers down when all DACs power
down in any of the power-down modes (see Table 17
and Power Down Modes section). The internal
reference automatically powers up when any DAC is
powered up.
Reference
Disable
Q1
Q2
R1
R2
Disabling Internal Reference:
To disable the internal reference, address the device
by writing the 8-bit address byte and then writing the
24-bit serial command shown in Table 1. When
performing a power cycle to reset the device, the
internal reference is put back into the default mode
(switched off).
Figure 88. Simplified Schematic of the Bandgap
Reference
Enable/Disable Internal Reference
The internal reference in the DAC7678 is disabled by
default for debugging, evaluation purposes, or when
SPACER
Table 1. Write Sequence for Enabling Internal Reference (Static Mode) (Internal Reference Powered On)
COMMAND AND ACCESS BYTE
MOST SIGNIFICANT DATA BYTE
LEAST SIGNIFICANT BYTE
C3
C2
C1
C0
A3
A2
A1
A0
DB15
DB14
DB13
DB12
DB11
DB10
DB9
DB8
DB7
DB6
DB5
DB4
DB3
DB2
DB1
DB0
1
0
0
0
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
1
X
X
X
X
Table 2. Write Sequence for Disabling Internal Reference (Static Mode) (Internal Reference Powered Off)
COMMAND AND ACCESS BYTE
MOST SIGNIFICANT DATA BYTE
LEAST SIGNIFICANT BYTE
C3
C2
C1
C0
A3
A2
A1
A0
DB15
DB14
DB13
DB12
DB11
DB10
DB9
DB8
DB7
DB6
DB5
DB4
DB3
DB2
DB1
DB0
1
0
0
0
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
0
X
X
X
X
24
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Flexible Mode (see Table 3, Table 4, Table 5 and
Table 6)
internal reference operating mode. When performing
a power cycle to reset the device, the internal
reference is switched off (default mode). In the
default mode, the internal reference remains powered
down until a valid write sequence is applied to power
up the internal reference. When the internal reference
is powered up in flexible mode, it remains powered
up, regardless of the state of the DACs.
Enabling Internal Reference:
Method 1) To enable the internal reference, write the
24-bit serial command shown in Table 3 after
properly addressing the device. When performing a
power cycle to reset the device, the internal reference
is switched off (default mode). In the default mode,
the internal reference is powered down until a valid
write sequence is applied to power up the internal
reference. If the internal reference is powered up, it
automatically powers down when all DACs power
down in any of the power-down modes (see the
Power Down Modes section). The internal reference
powers up automatically when any DAC is powered
up.
Disabling Internal Reference:
To disable the internal reference, write the 24-bit
serial command shown in Table 5 after properly
addressing the device. When performing a power
cycle to reset the device, the internal reference is
switched off (default mode). When the internal
reference is operated in Flexible mode, Static mode
is disabled and does not work. To switch from
Flexible mode to Static mode, use the command
shown in Table 6.
Method 2) To always enable the internal reference,
write the 24-bit serial command shown in Table 4
after properly addressing the device. When the
internal reference is always enabled, any power-down
command to the DAC channels does not change the
Table 3. Write Sequence for Enabling Internal Reference (Flexible Mode)
(Internal Reference Powered On)
COMMAND AND ACCESS BYTE
MOST SIGNIFICANT DATA BYTE
LEAST SIGNIFICANT BYTE
C3
C2
C1
C0
A3
A2
A1
A0
DB15
DB14
DB13
DB12
DB11
DB10
DB9
DB8
DB7
DB6
DB5
DB4
DB3
DB2
DB1
DB0
1
0
0
1
X
X
X
X
X
1
0
0
X
X
X
X
X
X
X
X
X
X
X
X
Table 4. Write Sequence for Enabling Internal Reference (Flexible Mode)
(Internal Reference Always Powered On)
COMMAND AND ACCESS BYTE
MOST SIGNIFICANT DATA BYTE
LEAST SIGNIFICANT BYTE
C3
C2
C1
C0
A3
A2
A1
A0
DB15
DB14
DB13
DB12
DB11
DB10
DB9
DB8
DB7
DB6
DB5
DB4
DB3
DB2
DB1
DB0
1
0
0
1
X
X
X
X
X
1
0
1
X
X
X
X
X
X
X
X
X
X
X
X
Table 5. Write Sequence for Disabling Internal Reference (Flexible Mode)
(Internal Reference Always Powered Down)
COMMAND AND ACCESS BYTE
MOST SIGNIFICANT DATA BYTE
LEAST SIGNIFICANT BYTE
C3
C2
C1
C0
A3
A2
A1
A0
DB15
DB14
DB13
DB12
DB11
DB10
DB9
DB8
DB7
DB6
DB5
DB4
DB3
DB2
DB1
DB0
1
0
0
1
X
X
X
X
X
1
1
0
X
X
X
X
X
X
X
0
X
X
X
X
Table 6. Write Sequence for Switching from Flexible Mode to Static Mode for Internal Reference
COMMAND AND ACCESS BYTE
MOST SIGNIFICANT DATA BYTE
LEAST SIGNIFICANT BYTE
C3
C2
C1
C0
A3
A2
A1
A0
DB15
DB14
DB13
DB12
DB11
DB10
DB9
DB8
DB7
DB6
DB5
DB4
DB3
DB2
DB1
DB0
1
0
0
1
X
X
X
X
X
0
X
X
X
X
X
X
X
X
X
X
X
X
X
X
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TWO-WIRE, I2C-COMPATIBLE INTERFACE
The I2C™ is a 2-wire serial interface developed by
Philips Semiconductor (see I2C™-Bus Specification,
Rev. 03, June 2007). 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.
The I2C specification states that the device that
controls communication is called a master, and the
devices that are controlled by the master are called
slaves. The master device generates the SCL signal.
The master device also generates special timing
conditions (start condition, repeated start condition,
and stop condition) on the bus to indicate the start or
stop of a data transfer. Device addressing is also
done by the master. The master device on an I2C bus
is usually a microcontroller or a digital signal
processor (DSP). The DAC7678 on the other hand,
operates as a slave device on the I2C bus. A slave
devcie acknowledges master's commands and upon
master's control, either receives or transmits data.
SDA
Other than specific timing signals, the I2C interface
works with serial bytes. At the end of each byte, a 9th
clock cycle is used to generate/detect an
acknowledge signal, Acknowledge is when the SDA
line is pulled low during the high period of the 9th
clock cycle. A not-acknowledge is when the SDA line
is left high during the high period of the 9th clock
cycle as shown in Figure 90.
Data Output
by Transmitter
Not Acknowledge
Data Output
by Receiver
Acknowledge
SCL from
Master
1
2
8
9
S
START
Condition
Clock Pulse for
Acknowledgement
Figure 90. Acknowledge and Not Acknowledge
on the I2C Bus
SDA
SCL
SCL
S
P
Start
Condition
Stop
Condition
Figure 89. Start and Stop Conditions
The DAC7678 normally operates as a slave receiver.
A master device writes to the DAC7678, a slave
receiver. However, if a master device inquires the
DAC7678 internal register data, the DAC7678
operates as a slave transmitter. In this case, the
master device reads from the DAC7678, a slave
transmitter. According to I2C™ terminology, read and
write are with respect to the master device.
The DAC7678 works as a slave and supports the
following data transfer modes, as defined in the I2C™
-Bus Specification:
• Standard mode (100 kbps)
• Fast mode (400 kbps)
• Fast mode+ (1.0Mbps) and
• High-Speed mode (3.4 Mbps)
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 fast
mode+ protocol is supported in terms of data transfer
speed but not output current. The low-level output
current would be 3mA similar to the case of standard
26
and fast modes. The protocol for high-speed mode is
different from the F/S-mode, and it is referred to as
HS-mode. The DAC7678 supports 7-bit addressing.
The 10-bit addressing and general call address are
not supported.
F/S Mode Protocol
• The master initiates data transfer by generating a
start condition. The start condition is when a
high-to-low transition occcurs on the SDA line
while SCL is high, as shown in Figure 90. All
I2C-compatible devices 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 is
valid. A valid data condition requires the SDA line
to be stable during the entire high period of the
clock pulse, as shown in Figure 91. 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 by pulling the SDA line
low during the entire high period of the ninth SCL
cycle, as shown in Figure 90 by pulling the SDA
line low during the entire high period of the 9th
SCL cycle. Upon detecting this acknowledge, the
master knows the communication link with a slave
has been established.
• The master generates further SCL cycles to either
transmit data to the slave (R/W bit 0) or receive
data from the slave (R/W bit 1). In either case, the
receiver needs to acknowledge the data sent by
the transmitter. So the 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-data bits
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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 low to high while the SCL line is high (see
Figure 89). This action releases the bus and stops
the communication link with the addressed slave.
All I2C-compatible devices recognize the stop
condition. Upon receipt of a stop condition, the
bus is released, and all slave devices then wait for
a start condition followed by a matching address.
•
all devices must recognize it and switch their
internal setting to support 3.4Mbps 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
F/S-mode, except that transmission speeds up to
3.4Mbps are allowed. A stop condition ends HS
mode and switches all the internal settings of the
slave devices to support F/S-mode. Instead of
using a stop condition, repeated start conditions
should be used to secure the bus in H/S-mode.
DAC7678 I2C UPDATE SEQUENCE
SDA
For a single update, the DAC7678 requires a start
condition, a valid I2C address, a command and
access (CA) byte, and two data bytes, the most
significant data byte (MSDB) and least significant
data byte (LSDB), as shown in Table 7.
SCL
Data Line Stable;
Data Valid
Change of Data Allowed
Figure 91. Bit Transfer on the I2C Bus
HS Mode Protocol
• When the bus is idle, both the SDA and SCL lines
are pulled high by the pull-up resistors.
• The master generates a start condition followed
by a valid serial byte containing H/S master code
00001XXX. This transmission is made in F/S
mode at no more than 1.0 Mbps. No device is
allowed to acknowledge the H/S master code, but
After each byte is received, the DAC7678
acknowledges by pulling the SDA line low during the
high period of a single clock pulse, as shown in
Figure 92. These four bytes and acknowledge cycles
make up the 36 clock cycles required for a single
update to occur. A valid I2C address selects the
DAC7678.
Recognize START or
REPEATED START
Condition
Recognize STOP or
REPEATED START
Condition
Generate ACKNOWLEDGE
Signal
P
SDA
Acknowledgement
Signal From Slave
MSB
Sr
Address
R/W
SCL
1
2
S
or
Sr
START or
REPEATED START
Condition
7
8
9
1
2
ACK
Clock Line Held Low While
Interrupts are Serviced
3 - 8
9
ACK
Sr
or
P
REPEATED START or
STOP
Condition
Figure 92. I2C Bus Protocol
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Table 7. Update Sequence
MSB
···
LSB
MSB
···
LSB
MSB
ACK
···
LSB
ACK
MSB
···
LSB
ACK
ACK
Address (A) Byte
Command/Access Byte
MSDB
LSDB
DB[32:24]
DB[23:16]
DB[15:8]
DB[7:0]
SPACING
The CA byte sets the operational mode of the
selected DAC7678. When the operational mode is
selected by this byte, the DAC7678 must receive two
data bytes, the most significant data byte (MSDB)
and least significant data byte (LSDB), for data
update to occur. The DAC7678 performs an update
on the falling edge of the acknowledge signal that
follows the LSDB.
maximum DAC update rate is limited to 22.22kSPS.
Using the Fast mode plus (clock = 1MHz), the
maximum DAC update rate is limited to 55.55kSPS.
When a stop condition is received, the DAC7678
releases the I2C bus and awaits a new start condition.
Address (A) Byte
The address byte, as shown in Table 8, is the first
byte received following the START condition from the
master device. The first four bits (MSBs) of the
address are factory preset to 1001. The next 3 bits of
the address are controlled by the ADDR pin(s). The
ADDR pin(s) inputs can be connected to AVDD, GND,
or left floating. The device address should be
determined before device power up. During power up
the device latches the values of the address pins and
consequently will respond to that particular address
according to Table 9 and Table 10. When using the
QFN package (DAC7678RGE), up to 8 devices can
be connected to the same I2C bus. When using the
TSSOP package (DAC7678PW), up to 3 devices can
be connected to the same I2C bus.
The CA byte does not have to be resent until a
change in operational mode is required. The bits of
the control byte continuously determine the type of
update performed. Thus, for the first update, the
DAC7678 requires a start condition, a valid I2C
address, the CA byte, and two data bytes (MSDB and
LSDB). For all consecutive updates, the DAC7678
needs only an MSDB and LSDB, as long as the CA
byte command remains the same.
When using the I2C HS mode (clock = 3.4MHz), each
12-bit DAC update other than the first update can be
done within 18 clock cycles (MSDB, acknowledge
signal, LSDB, acknowledge signal) at 188.88kSPS.
When using Fast mode (clock = 400kHz), the
Table 8. Address Byte
MSB
AD6
1
LSB
AD5
0
AD4
0
AD3
1
AD2
AD1
AD0
See Table 9 or Table 10 Slave Address column
R/W
0 or 1
Table 9. Address Format For QFN-24 (RGE) Package
SLAVE ADDRESS
ADDR1
ADDR0
1001 000
0
0
1001 001
0
1
1001 010
1
0
1001 011
1
1
1001 100
Float
0
1001 101
Float
1
1001 110
0
Float
1001 111
1
Float
Not supported
Float
Float
Table 10. Address Format For TSSOP-16 (PW) Package
28
SLAVE ADDRESS
ADDR0
1001 000
0
1001 010
1
1001 100
Float
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Command and Access (CA) Byte
The Command and Access Byte, as shown in
Table 11, controls which command is executed and
which register is being accessed when writing to or
reading from the DAC7678. See Table 12 for a list of
write and read commands.
Table 11. Command and Access Byte
MSB
C3
LSB
C2
C1
Command bits
C0
A3
A2
A1
Access bits
A0
Table 12. Command and Access Byte Format (1)
C3
C2
C1
C0
A3
A2
A1
A0
DESCRIPTION
Write Sequences
0
0
0
0
A3
A2
A1
A0
Write to DAC input register channel n
0
0
0
1
A3
A2
A1
A0
Select to update DAC register channel n
0
0
1
0
A3
A2
A1
A0
Write to DAC input register channel n, and update all DAC registers (global
software LDAC)
0
0
1
1
A3
A2
A1
A0
Write to DAC input register channel n, and update DAC register channel n
0
1
0
0
X
X
X
X
Power down/on DAC
0
1
0
1
X
X
X
X
Write to clear code register
0
1
1
0
X
X
X
X
Write to LDAC register
0
1
1
1
X
X
X
X
Software reset
1
0
0
0
X
X
X
X
Write to internal reference register
1
0
0
1
X
X
X
X
Write to additional internal reference register
Read Sequences
0
0
0
0
A3
A2
A1
A0
Read from DAC input register channel n
0
0
0
1
A3
A2
A1
A0
Read from DAC register channel n
0
1
0
0
X
X
X
X
Read from DAC power down register
0
1
0
1
X
X
X
X
Read from clear code register
0
1
1
0
X
X
X
X
Read from LDAC register
1
0
0
0
X
X
X
X
Read from internal reference register
1
0
0
1
X
X
X
X
Read from additional internal reference register
Access Sequences
C3
C2
C1
C0
0
0
0
0
DAC channel A
C3
C2
C1
C0
0
0
0
1
DAC channel B
C3
C2
C1
C0
0
0
1
0
DAC channel C
C3
C2
C1
C0
0
0
1
1
DAC channel D
C3
C2
C1
C0
0
1
0
0
DAC channel E
C3
C2
C1
C0
0
1
0
1
DAC channel F
C3
C2
C1
C0
0
1
1
0
DAC channel G
C3
C2
C1
C0
0
1
1
1
DAC channel H
C3
C2
C1
C0
1
1
1
1
All DAC channels, broadcast update
(1)
Any sequences other than the ones listed are invalid; improper use can cause incorrect device functionality.
Most Significant Data Byte (MSDB) and Least
Significant Data Byte (LSDB)
The MSDB and LSDB contain the data that are
passed to the register(s) specified by the CA byte, as
shown in Table 13 and Table 14. See Table 17 for a
complete list of write sequences and Table 18 for a
complete list of read sequences. The DAC7678
updates at the falling edge of the acknowledge signal
that follows the LSDB[0] bit.
Table 13. MSDB
MSB
DB15
LSB
DB14
DB13
DB12
DB11
DB10
DB9
DB8
Most Significant Data Byte (MSDB)
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Broadcast Address Byte
2. Then send a command byte for the register to be
read. The device will acknowledge this event
again.
3. Then send a repeated start with the slave
address and the R/W bit set to '1' for reading.
The device will also acknowledge this event.
4. Then the device writes the MSDB byte of the
addressed
register.
The
master
should
acknowledge this byte. Finally, the device writes
out the LSDB of the register as shown in
Table 16.
Broadcast addressing, see Table 15, is also
supported by DAC7678. Broadcast addressing can
be used for synchronously updating or powering
down multiple DAC7678 devices. DAC7678 is
designed to work with other members of the
DACx578 family to support multichannel synchronous
update. Using the broadcast address, DAC7678
responds regardless of the states of the address pins.
Broadcast is supported only in write mode (Master
writes to DAC7678).
An alternative reading method allows for reading back
the value of the last register written. The sequence is
a start/repeated start with slave address and the R/W
bit set to '1', and the two bytes of the last register are
read out.
DAC7678 I2C READ SEQUENCE
To read any register other than the power-down
register the following command sequence should be
used:
1. Send a start or repeated start command with a
Note that it is not possible to use the broadcast
slave address and the R/W bit set to '0' for
address for reading.
writing. The device will acknowledge this event.
Table 14. LSDB
MSB
LSB
DB7
DB6
DB5
DB4
DB3
DB2
DB1
1
1
DB0
Least Significant Data Byte (LSDB)
Table 15. Broadcast Address Byte
MSB
LSB
1
0
0
0
1
0
Table 16. Read Sequence
S
MSB
…
R/W(0)
ACK
Address Byte
From master
30
MSB
…
LSB
ACK
Command/Access Byte
Slave
From master
Sr
Sr
Slave
MSB
…
R/W(1)
ACK
Address Byte
From master
MSB
…
LSB
ACK
MSDB
slave
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From Slave
MSB
…
LSB
ACK
LSDB
Master
From Slave
Master
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Table 17. Control Matrix for Write Commands
COMMAND AND ACCESS BYTE
MOST SIGNIFICANT DATA BYTE
LEAST SIGNIFICANT DATA BYTE
DESCRIPTION
C3
C2
C1
C0
A3
A2
A1
A0
DB15
DB14
DB13
DB12
DB11
DB10
DB9
DB8
DB7
DB6
DB5
DB4
DB3
DB2
DB1
DB0
Write to DAC Input Register
0
0
0
0
0
0
0
0
Data[11:4]
Data[3:0]
X
X
X
X
Write to DAC input register of channel A
0
0
0
0
0
0
0
1
Data[11:4]
Data[3:0]
X
X
X
X
Write to DAC input register of channel B
0
0
0
0
0
0
1
0
Data[11:4]
Data[3:0]
X
X
X
X
Write to DAC input register of channel C
0
0
0
0
0
0
1
1
Data[11:4]
Data[3:0]
X
X
X
X
Write to DAC input register of channel D
0
0
0
0
0
1
0
0
Data[11:4]
Data[3:0]
X
X
X
X
Write to DAC input register of channel E
0
0
0
0
0
1
0
1
Data[11:4]
Data[3:0]
X
X
X
X
Write to DAC input register of channel F
0
0
0
0
0
1
1
0
Data[11:4]
Data[3:0]
X
X
X
X
Write to DAC input register of channel G
0
0
0
0
0
1
1
1
Data[11:4]
Data[3:0]
X
X
X
X
Write to DAC input register of channel H
0
0
0
0
1
X
X
X
X
X
X
X
Invalid code, no action performed
0
0
0
0
1
1
1
1
X
X
X
X
Broadcast mode–write to all DAC channels
X
X
X
X
X
X
X
X
X
Data[11:4]
X
X
X
Data[3:0]
Select to Update DAC Register
0
0
0
1
0
0
0
0
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Selects DAC channel A to be updated
0
0
0
1
0
0
0
1
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Selects DAC channel B to be updated
0
0
0
1
0
0
1
0
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Selects DAC channel C to be updated
0
0
0
1
0
0
1
1
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Selects DAC channel D to be updated
0
0
0
1
0
1
0
0
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Selects DAC channel E to be updated
0
0
0
1
0
1
0
1
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Selects DAC channel F to be updated
0
0
0
1
0
1
1
0
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Selects DAC channel G to be updated
0
0
0
1
0
1
1
1
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Selects DAC channel H to be updated
0
0
0
1
1
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Invalid code, no action performed
0
0
0
1
1
1
1
1
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Broadcast mode–selects all DAC channels to be
updated
Write to DAC Input Registers and Update DAC Register (Individual Software LDAC)
0
0
1
1
0
0
0
0
Data[11:4]
Data[3:0]
X
X
X
X
Write to DAC input register for channel A and
update channel A DAC register
0
0
1
1
0
0
0
1
Data[11:4]
Data[3:0]
X
X
X
X
Write to DAC input register for channel B and
update channel B DAC register
0
0
1
1
0
0
1
0
Data[11:4]
Data[3:0]
X
X
X
X
Write to DAC input register for channel C and
update channel C DAC register
0
0
1
1
0
0
1
1
Data[11:4]
Data[3:0]
X
X
X
X
Write to DAC input register for channel D and
update channel D DAC register
0
0
1
1
0
1
0
0
Data[11:4]
Data[3:0]
X
X
X
X
Write to DAC input register for channel E and
update channel E DAC register
0
0
1
1
0
1
0
1
Data[11:4]
Data[3:0]
X
X
X
X
Write to DAC input register for channel F and
update channel F DAC register
0
0
1
1
0
1
1
0
Data[11:4]
Data[3:0]
X
X
X
X
Write to DAC input register for channel G and
update channel G DAC register
0
0
1
1
0
1
1
1
Data[11:4]
Data[3:0]
X
X
X
X
Write to DAC input register for channel H and
update channel H DAC register
0
0
1
1
1
X
X
X
X
X
X
X
Invalid code, no action performed
0
0
1
1
1
1
1
1
X
X
X
X
Broadcast mode–write to all input registers and
update all DAC registers
X
X
X
X
X
X
X
X
X
Data[11:4]
X
Data[3:0]
X
X
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Table 17. Control Matrix for Write Commands (continued)
COMMAND AND ACCESS BYTE
MOST SIGNIFICANT DATA BYTE
LEAST SIGNIFICANT DATA BYTE
DESCRIPTION
C3
C2
C1
C0
A3
A2
A1
A0
DB15
DB14
DB13
DB12
DB11
DB10
DB9
DB8
DB7
DB6
DB5
DB4
DB3
DB2
DB1
DB0
Write to Select DAC Input Register and Update All DAC Registers (Global Software LDAC)
0
0
1
0
0
0
0
0
Data[11:4]
Data[3:0]
X
X
X
X
Write to DAC input register of channel A and
update all DAC registers
0
0
1
0
0
0
0
1
Data[11:4]
Data[3:0]
X
X
X
X
Write to DAC input register of channel B and
update all DAC registers
0
0
1
0
0
0
1
0
Data[11:4]
Data[3:0]
X
X
X
X
Write to DAC input register of channel C and
update all DAC registers
0
0
1
0
0
0
1
1
Data[11:4]
Data[3:0]
X
X
X
X
Write to DAC input register of channel D and
update all DAC registers
0
0
1
0
0
1
0
0
Data[11:4]
Data[3:0]
X
X
X
X
Write to DAC input register of channel E and
update all DAC registers
0
0
1
0
0
1
0
1
Data[11:4]
Data[3:0]
X
X
X
X
Write to DAC input register of channel F and
update all DAC registers
0
0
1
0
0
1
1
0
Data[11:4]
Data[3:0]
X
X
X
X
Write to DAC input register of channel G and
update all DAC registers
0
0
1
0
0
1
1
1
Data[11:4]
Data[3:0]
X
X
X
X
Write to DAC input register of channel H and
update all DAC registers
0
0
1
0
1
X
X
X
X
X
X
X
Invalid code, no action performed
0
0
1
0
1
1
1
1
X
X
X
X
Broadcast mode–write to all input registers and
update all DAC registers
X
X
X
X
X
X
X
X
X
X
Data[11:4]
X
X
Data[3:0]
Power-Down Register
0
1
0
0
X
X
X
X
X
PD1
PD0
DAC A
DAC B
DAC C
DAC D
DAC E
DAC F
DAC G
DAC H
X
X
X
X
X
0
1
0
0
X
X
X
X
X
0
0
DAC A
DAC B
DAC C
DAC D
DAC E
DAC F
DAC G
DAC H
X
X
X
X
X
Each DAC bit set to '1' powers on selected DACs
0
1
0
0
X
X
X
X
X
0
1
DAC A
DAC B
DAC C
DAC D
DAC E
DAC F
DAC G
DAC H
X
X
X
X
X
Each DAC bit set to '1' powers down selected
DACs. VOUT connected to GND through 1kΩ
pull-down resistor
0
1
0
0
X
X
X
X
X
1
0
DAC A
DAC B
DAC C
DAC D
DAC E
DAC F
DAC G
DAC H
X
X
X
X
X
Each DAC bit set to '1' powers down selected
DACs. VOUT connected to GND through 100kΩ
pull-down resistor
0
1
0
0
X
X
X
X
X
1
1
DAC A
DAC B
DAC C
DAC D
DAC E
DAC F
DAC G
DAC H
X
X
X
X
X
Each DAC bit set to '1' powers down selected
DACs. VOUT is High Z
Clear Code Register
0
1
0
1
X
X
X
X
X
X
X
X
X
X
X
X
X
X
CL1
CL0
X
X
X
X
0
1
0
1
X
X
X
X
X
X
X
X
X
X
X
X
X
X
0
0
X
X
X
X
Write to clear code register, CLR pin will clear to
zero scale
0
1
0
1
X
X
X
X
X
X
X
X
X
X
X
X
X
X
0
1
X
X
X
X
Write to clear code register, CLR pin will clear to
midscale
0
1
0
1
X
X
X
X
X
X
X
X
X
X
X
X
X
X
1
0
X
X
X
X
Write to clear code register, CLR pin will clear to
full scale
0
1
0
1
X
X
X
X
X
X
X
X
X
X
X
X
X
X
1
1
X
X
X
X
Write to clear code register disables CLR pin
1
0
X
X
X
X
DAC H
DAC G
DAC F
DAC E
DAC D
DAC C
DAC B
DAC A
X
X
X
X
X
X
X
X
When all DAC bits are set to '1', selected DACs
ignore the LDAC pin.
When all DAC bits are set to '0', selected DAC
registers update according to the LDAC pin.
LDAC Register
0
32
1
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Table 17. Control Matrix for Write Commands (continued)
COMMAND AND ACCESS BYTE
MOST SIGNIFICANT DATA BYTE
LEAST SIGNIFICANT DATA BYTE
DESCRIPTION
C3
C2
C1
C0
A3
A2
A1
A0
DB15
DB14
DB13
DB12
DB11
DB10
DB9
DB8
DB7
DB6
DB5
DB4
DB3
DB2
DB1
DB0
Software Reset
0
1
1
1
X
X
X
X
0
0
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Software reset (default). Equivalent to power-on
reset (POR).
0
1
1
1
X
X
X
X
0
1
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Software reset that sets device into High-Speed
mode
0
1
1
1
X
X
X
X
1
0
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Software reset that maintains High-Speed mode
state
Internal Reference in Regular/Static Mode
1
0
0
0
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
AR
X
X
X
X
1
0
0
0
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
0
X
X
X
X
Disable internal reference (Regular/Static mode)
X
X
X
Enable internal reference (Regular/Static mode). If
any DACs are powered on, the reference is on. If
all DACS are powered down, then reference is off.
X
1
0
0
0
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
1
Internal Reference in Flexible Mode
1
0
0
1
X
X
X
X
X
TR2
TR1
TR0
X
X
X
X
X
X
X
X
X
X
X
X
1
0
0
1
X
X
X
X
X
1
0
0
X
X
X
X
X
X
X
X
X
X
X
X
Reference powers down when all DACs power
down. Reference powers on when any DACs are
powered on.
1
0
0
1
X
X
X
X
X
1
0
1
X
X
X
X
X
X
X
X
X
X
X
X
Reference is powered on regardless of DAC power
state
1
0
0
1
X
X
X
X
X
1
1
0
X
X
X
X
X
X
X
X
X
X
X
X
Reference is powered down regardless of DAC
power state
1
0
0
1
X
X
X
X
X
0
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Reference follows Regular/Static mode reference
register
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Table 18. Control Matrix for Read Commands
COMMAND ACCESS BYTE
MOST SIGNIFICANT DATA BYTE
LEAST SIGNIFICANT DATA BYTE
DESCRIPTION
C3
C2
C1
C0
A3
A2
A1
A0
DB15
DB14
DB13
DB12
DB11
DB10
DB9
DB8
DB7
DB6
DB5
DB4
DB3
DB2
DB1
DB0
Input Register
0
0
0
0
0
0
0
0
Data[11:4]
Data[3:0]
X
X
X
X
Read from DAC input register channel A
0
0
0
0
0
0
0
1
Data[11:4]
Data[3:0]
X
X
X
X
Read from DAC input register channel B
0
0
0
0
0
0
1
0
Data[11:4]
Data[3:0]
X
X
X
X
Read from DAC input register channel C
0
0
0
0
0
0
1
1
Data[11:4]
Data[3:0]
X
X
X
X
Read from DAC input register channel D
0
0
0
0
0
1
0
0
Data[11:4]
Data[3:0]
X
X
X
X
Read from DAC input register channel E
0
0
0
0
0
1
0
1
Data[11:4]
Data[3:0]
X
X
X
X
Read from DAC input register channel F
0
0
0
0
0
1
1
0
Data[11:4]
Data[3:0]
X
X
X
X
Read from DAC input register channel G
0
0
0
0
0
1
1
1
Data[11:4]
Data[3:0]
X
X
X
X
Read from DAC input register channel H
0
0
0
0
1
X
X
X
X
X
X
X
Invalid code
X
X
X
X
X
X
X
X
X
X
X
X
DAC Register
0
0
0
1
0
0
0
0
Data[11:4]
Data[3:0]
X
X
X
X
Read DAC A DAC register
0
0
0
1
0
0
0
1
Data[11:4]
Data[3:0]
X
X
X
X
Read DAC B DAC register
0
0
0
1
0
0
1
0
Data[11:4]
Data[3:0]
X
X
X
X
Read DAC C DAC register
0
0
0
1
0
0
1
1
Data[11:4]
Data[3:0]
X
X
X
X
Read DAC D DAC register
0
0
0
1
0
1
0
0
Data[11:4]
Data[3:0]
X
X
X
X
Read DAC E DAC register
0
0
0
1
0
1
0
1
Data[11:4]
Data[3:0]
X
X
X
X
Read DAC F DAC register
0
0
0
1
0
1
1
0
Data[11:4]
Data[3:0]
X
X
X
X
Read DAC G DAC register
0
0
0
1
0
1
1
1
Data[11:4]
Data[3:0]
X
X
X
X
Read DAC H DAC register
0
0
0
1
1
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Invalid code
0
X
X
X
X
0
0
0
0
0
0
PD1
PD0
DAC A
DAC B
DAC C
DAC D
DAC E
DAC F
DAC G
DAC H
0
1
X
X
X
X
0
0
0
0
0
0
0
0
0
0
0
0
0
0
CL1
CL0
1
0
X
X
X
X
0
0
0
0
0
0
0
0
DAC H
DAC G
DAC F
DAC E
DAC D
DAC C
DAC B
DAC A
X
X
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
AR
Read reference register
X
X
0
0
0
0
0
0
0
0
0
0
0
0
0
TR2
TR1
TR0
Read additional reference register
Power Down Register
0
1
0
Read power down register
Clear Code Register
0
1
Read clear code register
LDAC Register
0
1
Read LDAC register
Internal Reference in Regular/Static Mode
1
0
0
0
X
X
Internal Reference in Flexible Mode
1
34
0
0
1
X
X
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POWER-ON RESET TO ZERO-SCALE OR
MID-SCALE
The DAC7678 contains a power-on reset (POR)
circuit that controls the output voltage during
power-on. For devices housed in the TSSOP
package, at power-on, all DAC registers are filled with
zeros and the output voltages of all DAC channels
are set to zero-scale. For devices housed in the QFN
package, all DAC registers are set to have all DAC
channels power on depending of the state of the
RSTSEL pin.
The RSTSEL pin value is read at power-on and
should be set prior to or simultaneously with AVDD.
For RSTSEL set to AVDD, the DAC channels are
loaded with midscale code. If RSTSEL is set to
ground, the DAC channels are loaded with zero-scale
code. All DAC channels remain in this state until a
valid write sequence and load command are sent to
the respective DAC channel. The power-on reset
function is useful in applications where it is important
to know the output state of each DAC while the
device is in the process of powering on.
The internal reference is powered off/down by default,
and remains that way until a valid reference-change
command is executed.
LDAC FUNCTIONALITY
The DAC7678 offers both software and hardware
simultaneous updates and control functions. The
DAC double-buffered architecture is designed so that
new data can be entered for each DAC without
disturbing the analog outputs.
The DAC7678 data updates can be performed either
in synchronous or asynchronous mode.
In synchronous mode, data are updated on the falling
edge of the acknowledge signal that follows LSDB.
For synchronous mode updates, the LDAC pin is not
required and must be connected to GND
permanently.
In asynchronous mode, the LDAC pin is used as a
negative-edge-triggered
timing
signal
for
asynchronous DAC updates. Multiple single-channel
updates can be performed in order to set different
channel buffers to desired values and then make a
falling edge on the LDAC pin. The data buffers of all
the channels must be loaded with the desired data
before an LDAC falling edge. After a high-to-low
LDAC transition, all DACs are simultaneously
updated with the last contents of the corresponding
data buffers. If the contents of a data buffer are not
changed by the serial interface, the corresponding
DAC output remains unchanged after the LDAC
trigger.
Alternatively, all DAC outputs can be updated
simultaneously using the built-in LDAC software
function. The LDAC register offers additional flexibility
and control, giving the ability to select which DAC
channel(s) should be updated simultaneously when
the hardware LDAC pin is being brought low. The
LDAC register is loaded with an 8-bit word (DB15 to
DB8) using control bits C3, C2, C1, and C0. The
default value for each bit, and therefore each DAC
channel, is zero and the external LDAC pin operates
in normal mode. If the LDAC register bit for a
selected DAC channel is set to '1', that DAC channel
ignores the external LDAC pin and updates only
through the software LDAC command. If, however,
the LDAC register bit is set to '0', the DAC channel is
controlled by the external LDAC pin.
This combination of a software and hardware
simultaneous update function is particularly useful in
applications where only selective DAC channels are
to be updated simultaneously, while keeping the other
channels unaffected and updating those channels
synchronously.
POWER-DOWN MODES
The DAC7678 has two separate sets of power-down
commands. One set is for the DAC channels and the
other set is for the internal reference. For more
information on powering down the reference see the
Enable/Disable Internal Reference section.
DAC Power-Down Commands
The DAC7678 uses four modes of operation. These
modes are accessed by using control bits C3, C2,
C1, and C0. The control bits must be set to '0100'.
When the control bits are set correctly, the four
different
power-down
modes
are
software
programmable by setting bits PD0 (DB13) and PD1
(DB14) in the control register. Table 19 shows how to
control the operating mode with data bits PD0 (DB13)
and PD1 (DB14). The DAC7678 treats the
power-down condition as data; all the operational
modes are still valid for power down. It is possible to
broadcast a power-down condition to all the
DAC7678s in a system. It is also possible to
power-down a channel and update data on other
channels. Furthermore, it is possible to write to the
DAC register/buffer of the DAC channel that is
powered down. When the DAC channel is then
powered on, it will contain this new value.
When both the PD0 and PD1 bits are set to '0', the
device works normally with its typical consumption of
1.49 mA at 5.5V. The reference is included with the
operation of all eight channels. However, for the three
power-down modes, the supply current falls to 0.42
µA at 5.5V (0.25 µA at 2.7V). Not only does the
supply current fall, but the output stage also switches
internally from the output amplifier to a resistor
network of known values as shown in Figure 93.
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The advantage of this switching is that the output
impedance of the device is known while it is in
power-down mode. As described in Table 19, there
are three different power-down options. VOUT can be
connected internally to GND through a 1kΩ resistor, a
100kΩ resistor, or open-circuited (High-Z). In other
words, C3, C2, C1, and C0 = '0100' and DB14 and
DB13 = '11' represent a power-down condition with
High-Z output impedance for a selected channel.
DB14 and DB13 = '01' represents a power-down
condition with 1kΩ output impedance and '10'
represents a power-down condition with 100kΩ
output impedance.
Table 19. DAC Operating Modes
PD1
(DB14)
PD0
(DB13)
0
0
Power on selected DACs
0
1
Power down selected DACs, 1kΩ to GND
1
0
Power down selected DACs, 100kΩ to GND
1
1
Power down selected DACs, High-Z to GND
DAC OPERATING MODES
SPACER
CLEAR CODE REGISTER AND CLR PIN
The DAC7678 contains a clear code register. The
clear code register can be accessed via the serial
interface (I2C) and is user configurable. Bringing the
CLR pin low clears the contents of all DAC registers
and all DAC buffers and replaces the code with the
code determined by the clear code register. The clear
code register can be written to by applying the
commands shown in Table 17. The default setting of
the clear code register sets the output of all DAC
channels to 0V when the CLR pin is brought low. The
CLR pin is falling-edge triggered; therefore, the
device exits clear code mode on the falling edge of
the acknowledge signal that follows LSDB of the next
write sequence. If the CLR pin is executed (brought
low) during a write sequence, this write sequence is
aborted and the DAC registers and DAC buffers are
cleared as described above.
When performing a software reset of the device, the
clear code register is reset to the default mode (DB5
= '0', DB4 = '0'). Setting the clear code register to
DB4 = '1' and DB5 = '1' ignores any activity on the
external CLR pin.
SOFTWARE RESET FUNCTION
Resistor
String
DAC
VOUTX
Amplifier
Power-Down
Circuitry
Resistor
Network
The DAC7678 contains a software reset feature.
When the software reset feature is executed, the
device (all DAC channels) are reset to the power-on
reset code. All registers inside the device are reset to
the respective default settings. The DAC7678 has an
additional feature of switching straight to high speed
mode after reset. Table 20 shows all the different
modes of the software reset function.
Table 20. Software Reset Modes
DB15
DB14
0
0
Default Software reset. Equivalent to
Power-on-Reset
x
1
Software reset and set part in High Speed
Mode
1
0
Software reset and maintain High Speed
Mode state
Figure 93. Output Stage During Power-Down
SPACER
36
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OPERATING MODES
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OPERATING EXAMPLES: DAC7678
For the following examples X = don’t care; value can be either '0' or '1'.
I2C Standard and Fast mode examples (ADDR0 and LDAC pin tied low) (TSSOP package)
Example 1: Write Mid Scale to Data Buffer A and Update Channel A Output
Start
Address
S
1001 0000
Command and
Access Byte
ACK
MSDB
ACK
0000 0000
LSDB
ACK
1000 0000
Stop
ACK
0000 XXXX
P
Channel A updates to Mid Scale after the falling edge of the last ACK cycle
SPACER
Example 2: Power-Down Channel B, C, and H with Hi-Z Output
Start
Address
S
1001 0000
Command and
Access Byte
ACK
MSDB
ACK
0100 XXXX
LSDB
ACK
X111 0000
Stop
ACK
110X XXXX
P
SPACER
Example 3: Read-back the value of the input register of Channel G
Start
Address
S
1001 0000
ACK
Command and
Access Byte
ACK
Repeated
Start
Address
Sr
1001 0001
0000 0110
MSDB (from
DAC7678)
ACK
ACK
XXXX XXXX
LSDB (from
DAC7678)
XXXX 0000
SPACER
Example 4: Write multiple bytes of data to Channel F
Write Full Scale and then Quarter Scale to Channel F
Start
Address
S
1001 0000
ACK
Command and
Access Byte
ACK
0000 0101
MSDB
LSDB
ACK
1111 1111
ACK*
1111 XXXX
MSDB
LSDB
ACK
0100 0000
ACK**
0000 XXXX
Stop
P
Channel F updates to Full Scale after the falling edge of the 4th ACK* cycle and then Channel F updates to
quarter scale after falling edge of the last ACK** cycle.
I2C High Speed mode example (ADDR0 and LDAC pin tied low) (TSSOP package)
SPACER
Example 5: Write Mid Scale and then Full Scale to all DAC channels
Start
HS
Master
Code
S
0000 1000
NOT
ACK
Repeated
Start
Address
Sr
1001 0000
ACK
Command
and Access
Byte
0011 1111
ACK
MSDB
1000 0000
ACK
LSDB
0000 XXXX
ACK
MSDB
1111 1111
ACK
LSDB
ACK
1111 XXXX
Stop
P
All Channels update to Mid Scale after the falling edge of the 4th ACK cycle and then all Channels update to Full
scale after falling edge of the last ACK cycle.
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APPLICATION INFORMATION
INTERNAL REFERENCE
Where:
The internal reference of the DAC7678 does not
require an external load capacitor for stability
because it is stable with any capacitive load.
However, for improved noise performance, an
external load capacitor of 100nF or larger connected
to the VREFIN/VREFOUT output is recommended.
Figure 94 shows the typical connections required for
operation of the DAC7678 internal reference. A
supply bypass capacitor at the AVDD input is also
recommended.
DAC7678
AVDD
1mF
VREF_MAX = maximum reference voltage observed
within temperature range TRANGE.
VREF_MIN = minimum reference voltage observed
within temperature range TRANGE.
VREF = 2.5V, target value for reference output
voltage.
The internal reference features an exceptional
maximum drift coefficient of 25ppm/°C from –40°C to
125°C. Temperature drift results are summarized in
the Typical Characteristics.
Noise Performance
1
LDAC
SCL 16
2
ADDR0
SDA 15
3
AVDD
GND 14
4
VOUTA
VOUTB 13
5
VOUTC
VOUTD 12
6
VOUTE
VOUTF 11
7
VOUTG
VOUTH 10
8
VREFIN/VREFOUT
CLR
Typical 0.1Hz to 10Hz voltage noise can be seen in
Figure 7, Internal Reference Noise. Additional filtering
can be used to improve output noise levels, although
care should be taken to ensure the output impedance
does not degrade the ac performance. The output
noise spectrum at VREFIN/VREFOUT without any
external components is depicted in Figure 6, Internal
Reference Noise Density vs Frequency. Internal
reference noise impacts the DAC output noise; see
the DAC Noise Performance section for more details.
9
Load Regulation
100nF
Figure 94. Typical Connections for Operating the
DAC7678 Internal Reference
Supply Voltage
The internal reference features an extremely low
dropout voltage. It can be operated with a supply of
only 5mV above the reference output voltage in an
unloaded condition. For loaded conditions, refer to
the Load Regulation section. The stability of the
internal reference with variations in supply voltage
(line regulation, dc PSRR) is also exceptional. Within
the specified supply voltage range of 2.7V to 5.5V,
the variation at VREFIN/VREFOUT is less than 100 µV/V;
see the Typical Characteristics.
Load regulation is defined as the change in reference
output voltage as a result of changes in load current.
The load regulation of the internal reference is
measured using force and sense contacts as shown
in Figure 5. The force and sense lines reduce the
impact of contact and trace resistance, resulting in
accurate measurement of the load regulation
contributed solely by the internal reference.
Measurement results are summarized in the Typical
Characteristics. Force and sense lines should be
used for applications that require improved load
regulation.
Output Pin
Contact and
Trace Resistance
VOUT
Force Line
IL
Temperature Drift
The internal reference is designed to exhibit minimal
drift error, defined as the change in reference output
voltage over varying temperature. The drift is
calculated using the box method described by
Equation 3:
æ VREF_MAX - VREF_MIN ö
6
Drift Error = ç
÷ ´ 10 (ppm/°C)
´
V
T
REF
RANGE
è
ø
Sense Line
Meter
Load
Figure 95. Accurate Load Regulation of the
DAC7678 Internal Reference
(3)
38
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Long-Term Stability
Long-term stability/aging refers to the change of the
output voltage of a reference over a period of months
or years. This effect lessens as time progresses (see
Figure 3, the typical long-term stability curve). The
typical drift value for the internal reference is 100ppm
from 0 hours to 2160 hours. This parameter is
characterized by powering-up 19 units and measuring
them at regular intervals for a period of 2160 hours.
Thermal Hysteresis
Thermal hysteresis for a reference is defined as the
change in output voltage after operating the device at
25°C, cycling the device through the operating
temperature range, and returning to 25°C. Hysteresis
is expressed by Equation 4:
æ |VREF_PRE - VREF_POST
VHYST = ç
ç
VREF_NOM
è
|ö
÷ ´ 106 (ppm/°C)
÷
ø
æ
æD
VO UT = ç VREF ´ Gain ´ ç IN
ç
è 2n
è
ö æ R1 + R 2 ö
æ R2 ö ö
÷ - VREF ´ ç
÷´ç R
÷÷
ø è
è R1 ø ø÷
1
ø
(5)
Where:
DIN = decimal equivalent of the binary code that
is loaded to the DAC register. It can range from 0
to 4095 (12 bit)
n = resolution in bits
Gain = 1 when External Reference is used and 2
when internal reference is used.
æ 10 ´ DIN ö
VOUT = ç
÷ - 5V
è
ø
2n
(6)
This result has an output voltage range of ±5V with
000h corresponding to a -5V output and FFFh
corresponding to a +5V output for the 12 bit
DAC7678.
(4)
V
AV
EXT
REF
Where:
VHYST = thermal hysteresis
VREF_PRE = output voltage measured at 25°C
pre-temperature cycling
VREF_POST = output voltage measured after the
device cycles through the temperature range of
–40°C to 125°C, and returns to 25°C.
R2
10kW
DD
+6V
R1
10kW
OPA703
AVDD
VREFIN/
VREFOUT
10mF
DAC NOISE PERFORMANCE
±5V
VOUT
DAC7678
0.1mF
GND
-6V
Serial Interface
Typical noise performance for the DAC7678 with the
internal reference enabled is shown in Figure 47.
Output noise spectral density at the VOUTX pin versus
frequency is depicted in Figure 47 for full-scale,
midscale, and zero-scale input codes. The typical
noise density for midscale code is 290nV/√Hz at
1kHz and 117nV/√Hz at 100 kHz when internal
reference is enabled. The typical noise density
reduces to 104nV/√Hz at 1kHz for mid scale code
with external reference as shown in Figure 48.
High-frequency noise can be improved by filtering the
reference noise. Integrated output noise between
0.1Hz and 10Hz is close to 3µVPP (midscale), as
shown in Figure 49.
BIPOLAR OPERATION USING THE DAC7678
The DAC7678 family of products is designed for
single-supply operation, but a bipolar output range is
also possible using the circuit in Figure 96. Rail-to-rail
operation at the amplifier output is achievable using
an OPA703 as the output amplifier.
The output voltage for any input code can be
calculated with Equation 5.
Figure 96. Bipolar Output Range Using External
Reference at 5V
MICROPROCESSOR INTERFACING
A basic connection diagram to the SCL and SDA pins
of the DAC7678 is shown in Figure 97. The DAC7678
interfaces directly to standard mode, fast mode and
high speed mode of 2-Wire compatible serial
interfaces. The DAC7678 does not perform clock
stretching (pulling SCL low), as a result it is not
necessary to provide for this function unless other
devices on the same bus require this function. Pull-up
resistors are required on both the SDA and SCL lines
as the bus-drivers are open-drain. The size of these
pull-up resistors depends on the operating speed and
capacitance of the bus lines. Higher value resistors
consume less power but increase transition time on
the bus limiting the bus speed. Long bus lines have
higher capacitance and require smaller pull-up
resistors to compensate. The resistors should not be
too small; if they are, bus drivers may not be able to
pull the bus lines low.
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DAC7678
SBAS493A – FEBRUARY 2010 – REVISED AUGUST 2010
www.ti.com
CONNECTING MULTIPLE DEVICES
VDD
Pull-Up Resistors
1kW to 10kW (typ)
Microcontroller or
Microprocessor
2
with I C Port
SCL
SDA
1
LDAC
SCL 16
2
ADDR0
SDA 15
3
AVDD
4
VOUTA
5
VOUTC
VOUTD 12
6
VOUTE
VOUTF 11
7
VOUTG
VOUTH 10
8
VREFIN/VREFOUT
GND 14
DAC7678
Top
View
Multiple devices of DAC7678 family can be
connected on the same bus. Using the address pin,
the DAC7678 can be set to one of three different I2C
addresses for the TSSOP package and one of eight
addresses for the QFN package. An example
showing three DAC7678 devices in TSSOP package
is shown if Figure 98. Note that only one set of
pull-up resistors is needed per bus. The pull-up
resistor values may need to be lowered slightly to
compensate for the additional bus capacitance due to
multiple devices and increased bus length.
VOUTB 13
CLR
Leave
Floating
VDD
9
Pull-Up Resistors
1kW to 10kW (typ)
Microcontroller or
Microprocessor
Figure 97. Typical Connections of the DAC7678
2
with I C Port
1
LDAC
SCL 16
2
ADDR0
SDA 15
3
AVDD
4
VOUTA
5
VOUTC
6
VOUTE
VOUTF 11
7
VOUTG
VOUTH 10
8
VREFIN/VREFOUT
GND 14
DAC7678
Top
View
VOUTB 13
VOUTD 12
CLR
9
SCL
SDA
VDD
1
LDAC
SCL 16
1
LDAC
SCL 16
2
ADDR0
SDA 15
2
ADDR0
SDA 15
3
AVDD
4
VOUTA
5
VOUTC
6
VOUTE
7
VOUTG
8
VREFIN/VREFOUT
DAC7678
Top
View
GND 14
3
AVDD
VOUTB 13
4
VOUTA
VOUTD 12
5
VOUTC
VOUTF 11
6
VOUTE
VOUTF 11
VOUTH 10
7
VOUTG
VOUTH 10
8
VREFIN/VREFOUT
CLR
9
GND 14
DAC7678
Top
View
VOUTB 13
VOUTD 12
CLR
9
Figure 98. Typical Connections of the Multiple
DAC7678 on the Same Bus
40
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DAC7678
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SBAS493A – FEBRUARY 2010 – REVISED AUGUST 2010
PARAMETER DEFINITIONS
With the increased complexity of many different
specifications listed in product data sheets, this
section summarizes selected specifications related to
digital-to-analog converters.
STATIC PERFORMANCE
Static performance parameters are specifications
such as differential nonlinearity (DNL) or integral
nonlinearity (INL). These are dc specifications and
provide information on the accuracy of the DAC. They
are most important in applications where the signal
changes slowly and accuracy is required.
Resolution
Generally, the DAC resolution can be expressed in
different forms. Specifications such as IEC 60748-4
recognize the numerical, analog, and relative
resolution. The numerical resolution is defined as the
number of digits in the chosen numbering system
necessary to express the total number of steps of the
transfer characteristic, where a step represents both
a digital input code and the corresponding discrete
analogue output value. The most commonly-used
definition of resolution provided in data sheets is the
numerical resolution expressed in bits.
Least Significant Bit (LSB)
The least significant bit (LSB) is defined as the
smallest value in a binary coded system. The value of
the LSB can be calculated by dividing the full-scale
output voltage by 2n, where n is the resolution of the
converter.
Most Significant Bit (MSB)
The most significant bit (MSB) is defined as the
largest value in a binary coded system. The value of
the MSB can be calculated by dividing the full-scale
output voltage by 2. Its value is one-half of full-scale.
Relative Accuracy or Integral Nonlinearity (INL)
Relative accuracy or integral nonlinearity (INL) is
defined as the maximum deviation between the real
transfer function and a straight line passing through
the endpoints of the ideal DAC transfer function. INL
is measured in LSBs.
Differential Nonlinearity (DNL)
Differential nonlinearity (DNL) is defined as the
maximum deviation of the real LSB step from the
ideal 1LSB step. Ideally, any two adjacent digital
codes correspond to output analog voltages that are
exactly one LSB apart. If the DNL is less than 1LSB,
the DAC is said to be monotonic.
Full-Scale Error
Full-scale error is defined as the deviation of the real
full-scale output voltage from the ideal output voltage
while the DAC register is loaded with the full-scale
code (0xFFF). Ideally, the output should be AVDD – 1
LSB. The full-scale error is expressed in percent of
full-scale range (%FSR).
Offset Error
The offset error is defined as the difference between
actual output voltage and the ideal output voltage in
the linear region of the transfer function. This
difference is calculated by using a straight line
defined by two codes (code 30 and 4050). Since the
offset error is defined by a straight line, it can have a
negative or positive value. Offset error is measured in
mV.
Zero-Code Error
The zero-code error is defined as the DAC output
voltage, when all '0's are loaded into the DAC
register. Zero-scale error is a measure of the
difference between actual output voltage and ideal
output voltage (0V). It is expressed in mV. It is
primarily caused by offsets in the output amplifier.
Gain Error
Gain error is defined as the deviation in the slope of
the real DAC transfer characteristic from the ideal
transfer function. Gain error is expressed as a
percentage of full-scale range (%FSR).
Full-Scale Error Drift
Full-scale error drift is defined as the change in
full-scale error with a change in temperature.
Full-scale error drift is expressed in units of µV/°C.
Offset Error Drift
Offset error drift is defined as the change in offset
error with a change in temperature. Offset error drift
is expressed in µV/°C.
Zero-Code Error Drift
Zero-code error drift is defined as the change in
zero-code error with a change in temperature.
Zero-code error drift is expressed in µV/°C.
Gain Temperature Coefficient
The gain temperature coefficient is defined as the
change in gain error with changes in temperature.
The gain temperature coefficient is expressed in ppm
of FSR/°C.
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DAC7678
SBAS493A – FEBRUARY 2010 – REVISED AUGUST 2010
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Power-Supply Rejection Ratio (PSRR)
Power-supply rejection ratio (PSRR) is defined as the
ratio of change in output voltage to a change in
supply voltage for a full-scale output of the DAC. The
PSRR of a device indicates how the output of the
DAC is affected by changes in the supply voltage.
PSRR is measured in decibels (dB).
Monotonicity
Monotonicity is defined as a slope whose sign does
not change. If a DAC is monotonic, the output
changes in the same direction or remains at least
constant for each step increase (or decrease) in the
input code.
DYNAMIC PERFORMANCE
Dynamic performance parameters are specifications
such as settling time or slew rate, which are important
in applications where the signal rapidly changes
and/or high frequency signals are present.
Slew Rate
The output slew rate (SR) of an amplifier or other
electronic circuit is defined as the maximum rate of
change of the output voltage for all possible input
signals.
æ DVOUT (t ) ö
SR = max ç
÷
Dt
è
ø
Where ΔVOUT(t) is the output produced by the
amplifier as a function of time t.
Output Voltage Settling Time
Settling time is the total time (including slew time) for
the DAC output to settle within an error band around
its final value after a change in input. Settling times
are specified to within ±0.003% (or whatever value is
specified) of full-scale range (FSR).
Code Change/Digital-to-Analog Glitch Energy
Digital-to-analog glitch impulse is the impulse injected
into the analog output when the input code in the
DAC register changes state. It is normally specified
as the area of the glitch in nanovolt-seconds (nV-s),
and is measured when the digital input code is
changed by 1LSB at the major carry transition.
Digital Feed-through
Digital feed-through is defined as impulse seen at the
output of the DAC from the digital inputs of the DAC.
It is measured when the DAC output is not updated. It
is specified in nV-s, and measured with a full-scale
code change on the data bus; that is, from all '0's to
all '1's and vice versa.
42
Channel-to-Channel DC Crosstalk
Channel-to-channel dc crosstalk is defined as the dc
change in the output level of one DAC channel in
response to a change in the output of another DAC
channel. It is measured with a full-scale output
change on one DAC channel while monitoring
another DAC channel remains at midscale. It is
expressed in LSB.
DAC Output Noise Density
Output noise density is defined as internallygenerated random noise. Random noise is
characterized as a spectral density (nV/√Hz). It is
measured by loading the DAC to midscale and
measuring noise at the output.
DAC Output Noise
DAC output noise is defined as any voltage deviation
of DAC output from the desired value (within a
particular frequency band). It is measured with a DAC
channel kept at midscale while filtering the output
voltage within a band of 0.1Hz to 10Hz and
measuring its amplitude peaks. It is expressed in
terms of peak-to-peak voltage (Vpp).
Full-Scale Range (FSR)
Full-scale range (FSR) is the difference between the
maximum and minimum analog output values that the
DAC is specified to provide; typically, the maximum
and minimum values are also specified. For an n-bit
DAC, these values are usually given as the values
matching with code 0 and 2n–1.
LAYOUT
A precision analog component requires careful layout,
adequate bypassing, and clean, well-regulated power
supplies. The DAC7678 offers single-supply
operation, and is often used in close proximity with
digital logic, microcontrollers, microprocessors, and
digital signal processors. The more digital logic
present in the design and the higher the switching
speed, the more difficult it is to keep digital noise
from appearing at the output. As a result of the single
ground
pin
of
the
DAC7678,
all
return
currents(including digital and analog return currents
for the DAC) must flow through a single point. Ideally,
GND would be connected directly to an analog
ground plane. This plane would be separate from the
ground connection for the digital components until
they were connected at the power-entry point of the
system.
The power applied to AVDD should be well-regulated
and low noise. Switching power supplies and dc/dc
converters often have high-frequency glitches or
spikes riding on the output voltage. In addition, digital
components can create similar high-frequency spikes
as their internal logic switches states. This noise can
easily couple into the DAC output voltage through
various paths between the power connections and
analog output. As with the GND connection, AVDD
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SBAS493A – FEBRUARY 2010 – REVISED AUGUST 2010
should be connected to a power-supply plane or trace
that is separate from the connection for digital logic
until they are connected at the power-entry point. In
addition, a 1µF to 10µF capacitor and 0.1µF bypass
capacitor are strongly recommended. In some
situations, additional bypassing may be required,
such as a 100µF electrolytic capacitor or even a Pi
filter made up of inductors and capacitors – all
designed to essentially low-pass filter the supply and
remove the high-frequency noise.
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43
DAC7678
SBAS493A – FEBRUARY 2010 – REVISED AUGUST 2010
www.ti.com
REVISION HISTORY
Changes from Original (February 2010) to Revision A
•
44
Page
Changed the data sheet From: Product Preview status To : Production ............................................................................. 1
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MECHANICAL DATA
MTSS001C – JANUARY 1995 – REVISED FEBRUARY 1999
PW (R-PDSO-G**)
PLASTIC SMALL-OUTLINE PACKAGE
14 PINS SHOWN
0,30
0,19
0,65
14
0,10 M
8
0,15 NOM
4,50
4,30
6,60
6,20
Gage Plane
0,25
1
7
0°– 8°
A
0,75
0,50
Seating Plane
0,15
0,05
1,20 MAX
PINS **
0,10
8
14
16
20
24
28
A MAX
3,10
5,10
5,10
6,60
7,90
9,80
A MIN
2,90
4,90
4,90
6,40
7,70
9,60
DIM
4040064/F 01/97
NOTES: A.
B.
C.
D.
All linear dimensions are in millimeters.
This drawing is subject to change without notice.
Body dimensions do not include mold flash or protrusion not to exceed 0,15.
Falls within JEDEC MO-153
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
PACKAGE OPTION ADDENDUM
www.ti.com
16-Aug-2010
PACKAGING INFORMATION
Orderable Device
Status
(1)
Package Type Package
Drawing
Pins
Package Qty
Eco Plan
(2)
Lead/
Ball Finish
MSL Peak Temp
(3)
Samples
(Requires Login)
DAC7678SPW
ACTIVE
TSSOP
PW
16
90
Green (RoHS
& no Sb/Br)
CU NIPDAU Level-3-260C-168 HR
Request Free Samples
DAC7678SPWR
ACTIVE
TSSOP
PW
16
2000
Green (RoHS
& no Sb/Br)
CU NIPDAU Level-3-260C-168 HR
Purchase Samples
DAC7678SRGER
ACTIVE
VQFN
RGE
24
3000
Green (RoHS
& no Sb/Br)
CU NIPDAU Level-3-260C-168 HR
Purchase Samples
DAC7678SRGET
ACTIVE
VQFN
RGE
24
250
Green (RoHS
& no Sb/Br)
CU NIPDAU Level-3-260C-168 HR
Request Free Samples
(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
DAC7678SPWR
TSSOP
PW
16
2000
330.0
12.4
6.9
5.6
1.6
8.0
12.0
Q1
DAC7678SRGER
VQFN
RGE
24
3000
330.0
12.4
4.25
4.25
1.15
8.0
12.0
Q2
DAC7678SRGET
VQFN
RGE
24
250
180.0
12.4
4.25
4.25
1.15
8.0
12.0
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)
DAC7678SPWR
TSSOP
PW
16
2000
367.0
367.0
35.0
DAC7678SRGER
VQFN
RGE
24
3000
367.0
367.0
35.0
DAC7678SRGET
VQFN
RGE
24
250
210.0
185.0
35.0
Pack Materials-Page 2
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