AD ADT7320 ±0.25â°c accurate, 16-bit digital spi temperature sensor Datasheet

±0.25°C Accurate, 16-Bit
Digital SPI Temperature Sensor
ADT7320
Preliminary Technical Data
FEATURES
GENERAL DESCRIPTION
Temperature accuracy ±0.25°C from −20°C to +105°C
13- or 16-bit user-selectable temperature-to-digital
converter
Low drift silicon temperature sensor
No temperature calibration/correction required by user
Power saving 1 sample per second (SPS) mode
Fast first conversion on power-up of 6 ms
SPI-compatible interface
Operating temperature from −40°C to +150°C
Operating voltage: 2.7 V to 5.5 V
Critical overtemperature indicator
Programmable overtemperature/undertemperature interrupt
Low power consumption: 700 μW typical at 3.3 V
Shutdown mode for lower power: 7 μW typical at 3.3 V
16-lead RoHS-compliant LFCSP package
The ADT7320 is a high accuracy digital temperature sensor
offering breakthrough performance over a wide industrial range,
housed in an LFCSP package. It contains a band gap temperature
reference and a 13-bit analog-to-digital converter (ADC) to
monitor and digitize the temperature to a 0.0625°C resolution.
The ADC resolution, by default, is set to 13 bits (0.0625°C).
This can be changed to 16 bits (0.0078°C) by setting Bit 7 in the
configuration register (Register Address 0x01).
APPLICATIONS
The CT pin is an open-drain output that becomes active when
the temperature exceeds a programmable critical temperature
limit. The default critical temperature limit is 147°C. The INT
pin is also an open-drain output that becomes active when the
temperature exceeds a programmable limit. The INT and CT
pins can operate in either comparator or interrupt mode.
The ADT7320 is guaranteed to operate over supply voltages from
2.7 V to 5.5 V. Operating at 3.3 V, the average supply current is
typically 210 μA. The ADT7320 has a shutdown mode that
powers down the device and offers a shutdown current of
typically 2 μA. The ADT7320 is rated for operation over the
−40°C to +150°C temperature range.
RTD and thermistor replacement
Medical equipment
Cold junction compensation
Industrial controls and test
Food transportation and storage
Environmental monitoring and HVAC
FUNCTIONAL BLOCK DIAGRAM
ADT7320
SPI INTERFACE
DOUT 2
DIN 3
CS 4
INTERNAL
REFERENCE
INTERNAL
OSCILLATOR
6 CT
TCRIT
TEMPERATURE
VALUE
REGISTER
CONFIGURATION
AND STATUS
REGISTERS
THYST
REGISTER
TCRIT
REGISTER
THIGH
REGISTER
TLOW
REGISTER
TEMPERATURE
SENSOR
Σ-Δ
MODULATOR
5 INT
THIGH
FILTER
LOGIC
TLOW
7
GND
8
VDD
09012-001
SCLK 1
Figure 1.
Rev. PrA
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ADT7320
Preliminary Technical Data
TABLE OF CONTENTS
Features .............................................................................................. 1
Status Register ............................................................................. 14
Applications ....................................................................................... 1
Configuration Register .............................................................. 15
General Description ......................................................................... 1
Temperature Value Register ...................................................... 16
Functional Block Diagram .............................................................. 1
ID Register................................................................................... 16
Revision History ............................................................................... 2
TCRIT Setpoint Register ............................................................... 16
Specifications..................................................................................... 3
THYST Setpoint Register............................................................... 17
SPI Timing Specifications ........................................................... 4
THIGH Setpoint Register .............................................................. 17
Absolute Maximum Ratings............................................................ 5
TLOW Setpoint Register ............................................................... 17
ESD Caution .................................................................................. 5
Serial Interface ................................................................................ 18
Pin Configuration and Function Descriptions ............................. 6
SPI Command Byte .................................................................... 18
Typical Performance Characteristics ............................................. 7
Writing Data ............................................................................... 19
Theory of Operation ........................................................................ 9
Reading Data............................................................................... 20
Circuit Information ...................................................................... 9
Interfacing to DSPs or Microcontrollers ................................. 20
Converter Details.......................................................................... 9
Serial Interface Reset.................................................................. 20
Temperature Measurement ......................................................... 9
INT and CT Outputs...................................................................... 21
One-Shot Mode .......................................................................... 10
Undertemperature and Overtemperature Detection ............ 21
1 SPS Mode .................................................................................. 10
Applications Information .............................................................. 23
Continuous Read Mode ............................................................. 12
Thermal Response Time ........................................................... 23
Shutdown ..................................................................................... 12
Supply Decoupling ..................................................................... 23
Fault Queue ................................................................................. 12
Temperature Monitoring ........................................................... 23
Temperature Data Format ......................................................... 13
Outline Dimensions ....................................................................... 24
Temperature Conversion Formulas ......................................... 13
Ordering Guide .......................................................................... 24
Registers ........................................................................................... 14
REVISION HISTORY
6/10—Revision PrA: Preliminary Version
Rev. PrA | Page 2 of 24
Preliminary Technical Data
ADT7320
SPECIFICATIONS
TA = −40°C to +125°C, VDD = 2.7 V to 5.5 V, unless otherwise noted.
Table 1.
Parameter
TEMPERATURE SENSOR AND ADC
Accuracy1
Min
ADC Resolution
Temperature Resolution
13 Bit
16 Bit
Temperature Conversion Time
Fast Temperature Conversion Time
1 SPS Conversion Time
Temperature Hysteresis
Repeatability4
Drift5
DC PSRR
DIGITAL OUTPUTS (OPEN DRAIN)
High Output Leakage Current, IOH
Output High Current
Output Low Voltage, VOL
Output High Voltage, VOH
Output Capacitance, COUT
DIGITAL INPUTS
Input Current
Input Low Voltage, VIL
Input High Voltage, VIH
Pin Capacitance
DIGITAL OUTPUT (DOUT)
Output High Voltage, VOH
Output Low Voltage, VOL
Output Capacitance, COUT
POWER REQUIREMENTS
Supply Voltage
Supply Current
At 3.3 V
At 5.5 V
1 SPS Current
At 3.3 V
At 5.5 V
Typ
Max
Unit
Test Conditions/Comments
±0.202
±0.25
±0.50
±0.503
±0.75
−0.85
−1.0
13
°C
°C
°C
°C
°C
°C
°C
Bits
16
Bits
TA = −10°C to +85°C, VDD = 3.0 V
TA = −20°C to +105°C, VDD = 2.7 V to 3.3 V
TA = −40°C to +125°C, VDD = 2.7 V to 3.3 V
TA = −10°C to +105°C, VDD = 4.5 V to 5.5 V
TA = −40°C to +125°C, VDD = 4.5 V to 5.5 V
TA = 125°C to 150°C, VDD = 4.5 V to 5.5 V
TA = 125°C to 150°C, VDD = 2.7 V to 3.3 V
Twos complement temperature value of sign bit plus 12 ADC
bits (power-up default resolution)
Twos complement temperature value of sign bit plus 15 ADC
bits (Bit 7 = 1 in the configuration register)
0.0625
0.0078
240
6
60
0.02
±0.015
0.0073
0.1
°C
°C
ms
ms
ms
°C
°C
°C
°C/V
13-bit resolution (sign + 12 bit)
16-bit resolution (sign + 15 bit)
Continuous conversion and one-shot conversion mode
First conversion on power-up only
Conversion time for 1 SPS mode
Temperature cycle = 25°C to 125°C and back to 25°C
TA = 25°C
500 hour stress test at 150°C with VDD = 5.0 V
TA = 25°C
5
1
0.4
μA
mA
V
V
pF
CT and INT pins pulled up to 5.5 V
VOH = 5.5 V
IOL = 2 mA @ 5.5 V, IOL = 1 mA @ 3.3 V
±1
0.4
VIN = 0 V to VDD
10
μA
V
V
pF
0.4
50
V
V
pF
ISOURCE = ISINK = 200 μA
IOL = 200 μA
5.5
V
250
300
μA
μA
Peak current while converting, SPI interface inactive
Peak current while converting, SPI interface inactive
μA
μA
VDD = 3.3 V, 1 SPS mode, TA = 25°C
VDD = 5.5 V, 1 SPS mode, TA = 25°C
0.1
0.7 × VDD
3
0.7 × VDD
5
VOH − 0.3
2.7
210
230
46
65
Rev. PrA | Page 3 of 24
ADT7320
Preliminary Technical Data
Shutdown Current
At 3.3 V
At 5.5 V
Power Dissipation Normal Mode
Power Dissipation 1 SPS
2.0
4.4
700
150
15
25
μA
μA
μW
μW
Supply current in shutdown mode
Supply current in shutdown mode
VDD = 3.3 V, normal mode at 25°C
Power dissipated for VDD = 3.3 V, TA = 25°C
1
Accuracy includes repeatability.
The equivalent three-sigma limits are ±0.15°C. This three-sigma specification is provided to enable comparison with other vendors who use these limits.
3
For higher accuracy at 5 V operation, contact an Analog Devices, Inc., sales representative.
4
Based on a floating average of 10 readings.
5
Drift includes solder heat resistance (SHR) and lifetime tests performed as per JEDEC Standard JESD22-A108.
2
SPI TIMING SPECIFICATIONS
TA = −40°C to +150°C, VDD = 2.7 V to 5.5 V, unless otherwise noted. All input signals are specified with rise time (tR) = fall time (tF) = 5 ns
(10% to 90% of VDD) and timed from a voltage level of 1.6 V.
Table 2.
Parameter1, 2
t1
t2
t3
t4
t5
t6
Limit at TMIN, TMAX (B Version)
0
100
100
30
25
0
60
80
10
80
0
0
60
80
10
t74
t8
t9
t10
Unit
ns min
ns min
ns min
ns min
ns min
ns min
ns max
ns max
ns min
ns max
ns min
ns min
ns max
ns max
ns min
Conditions/Comments
CS falling edge to SCLK active edge setup time3
SCLK high pulse width
SCLK low pulse width
Data valid to SCLK edge setup time
Data valid to SCLK edge hold time
SCLK active edge to data valid delay3
VDD = 4.5 V to 5.5 V
VDD = 2.7 V to 3.6 V
Bus relinquish time after CS inactive edge
CS rising edge to SCLK edge hold time
CS falling edge to DOUT active time
VDD = 4.5 V to 5.5 V
VDD = 2.7 V to 3.6 V
SCLK inactive edge to DOUT high
1
Sample tested during initial release to ensure compliance. All input signals are specified with tR = tF = 5 ns (10% to 90% of VDD) and timed from a voltage level of 1.6 V.
See Figure 2.
3
SCLK active edge is falling edge of SCLK.
4
This means that the times quoted in the timing characteristics are the true bus relinquish times of the part and, as such, are independent of external bus loading
capacitances.
2
CS
t2
1
SCLK
t4
t8
t3
2
3
7
1
2
7
8
t5
MSB
DIN
8
LSB
t6
t9
DOUT
MSB
Figure 2. Detailed SPI Timing Diagram
Rev. PrA | Page 4 of 24
t10
t7
LSB
09012-002
t1
Preliminary Technical Data
ADT7320
ABSOLUTE MAXIMUM RATINGS
Stresses above those listed under Absolute Maximum Ratings
may cause permanent damage to the device. This is a stress
rating only; functional operation of the device at these or any
other conditions above those indicated in the operational
section of this specification is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect
device reliability.
Table 3.
Parameter
VDD to GND
DIN Input Voltage to GND
DOUT Voltage to GND
SCLK Input Voltage to GND
CS Input Voltage to GND
CT and INT Output Voltage to GND
ESD Rating (Human Body Model)
Operating Temperature Range
Storage Temperature Range
Maximum Junction Temperature, TJMAX
16-Lead LFCSP
Power Dissipation1
Thermal Impedance3
θJA, Junction-to-Ambient (Still Air)
θJC, Junction-to-Case
IR Reflow Soldering
Peak Temperature (RoHSCompliant Package)
Time at Peak Temperature
Ramp-Up Rate
Ramp-Down Rate
Time from 25°C to Peak Temperature
Rating
−0.3 V to +7 V
−0.3 V to VDD + 0.3 V
−0.3 V to VDD + 0.3 V
−0.3 V to VDD + 0.3 V
−0.3 V to VDD + 0.3 V
−0.3 V to VDD + 0.3 V
2.0 kV
−40°C to +150°C
−65°C to +160°C
150°C
ESD CAUTION
WMAX = (TJMAX − TA2)/θJA
121°C/W
56°C/W
220°C
260°C (0°C)
20 sec to 40 sec
3°C/sec maximum
−6°C/sec maximum
8 minutes maximum
1
Values relate to package being used on a standard 2-layer PCB. This gives a
worst-case θJA and θJC.
2
TA = ambient temperature.
3
Junction-to-case resistance is applicable to components featuring a
preferential flow direction, for example, components mounted on a heat
sink. Junction-to-ambient is more useful for air-cooled, PCB-mounted
components.
Rev. PrA | Page 5 of 24
ADT7320
Preliminary Technical Data
13 NC
14 NC
15 NC
16 NC
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
SCLK 1
12 VDD
ADT7320
DOUT 2
10 CT
9 INT
NC 8
NC 6
NC 7
NC 5
CS 4
NOTES
1. NC = NO CONNECT.
2. THE EXPOSED PADDLE IS CONNECTED INTERNALLY.
FOR INCREASED RELIABILITY OF THE SOLDER
JOINTS AND MAXIMUM THERMAL CAPABILITY, IT IS
RECOMMENDED THAT THE PAD BE SOLDERED TO
THE GROUND PLANE.
09012-003
DIN 3
11 GND
TOP VIEW
(Not to Scale)
Figure 3. Pin Configuration
Table 4. Pin Function Descriptions
Pin No.
1
Mnemonic
SCLK
2
3
DOUT
DIN
4
5
6
7
8
9
CS
NC
NC
NC
NC
INT
10
CT
11
12
GND
VDD
13
14
15
16
NC
NC
NC
NC
EPAD
Description
Serial Clock Input. The serial clock is used to clock in and clock out data to and from any register of the
ADT7320.
Serial Data Output. Data is clocked out on the SCLK falling edge and is valid on the SCLK rising edge.
Serial Data Input. Serial data to be loaded to the control registers of the part is provided on this input. Data
is clocked into the registers on the rising edge of SCLK.
Chip Select Input. The device is selected when this input is low. The device is disabled when this pin is high.
No Connect.
No Connect.
No Connect.
No Connect.
Overtemperature and Undertemperature Indicator. Logic output. Power-up default setting is as an active
low comparator interrupt. Open-drain configuration. A pull-up resistor is required, typically 10 kΩ.
Critical Overtemperature Indicator. Logic output. Power-up default polarity is active low. Open-drain
configuration. A pull-up resistor is required, typically 10 kΩ.
Analog and Digital Ground.
Positive Supply Voltage (2.7 V to 5.5 V). The supply should be decoupled with a 0.1 μF ceramic capacitor to
ground.
No Connect.
No Connect.
No Connect.
No Connect.
The exposed paddle is connected internally. For increased reliability of the solder joints and maximum
thermal capability, it is recommended that the pad be soldered to the ground plane.
Rev. PrA | Page 6 of 24
Preliminary Technical Data
ADT7320
TYPICAL PERFORMANCE CHARACTERISTICS
0.30
1.0
5.5V CONTINUOUS
CONVERSION
0.5
3.0V CONTINUOUS
CONVERSION
0.20
IDD (mA)
TEMPERATURE ERROR (°C)
0.25
0
0.15
0.10
5.5V 1SPS
–0.5
0.05
–10
10
30
50
70
90
110
130
TEMPERATURE (°C)
0
–100
–50
0
50
100
150
200
09012-007
–30
09012-004
–1.0
–50
200
09012-025
3.0V 1SPS
TEMPERATURE (°C)
Figure 4. Temperature Accuracy at 3 V
Figure 6. Operating Supply Current vs. Temperature
1.0
6
SHUTDOWN IDD (µA)
0
5.5V
4
5.0V
3
4.5V
2
3.6V
–0.5
1
–1.0
–50
–30
–10
10
30
50
70
90
TEMPERATURE (°C)
110
130
09012-005
TEMPERATURE ERROR (°C)
5
0.5
Figure 5. Temperature Accuracy at 5 V
0
–100
3.0V
2.7V
–50
0
50
100
150
TEMPERATURE (°C)
Figure 7. Shutdown Current vs. Temperature
Rev. PrA | Page 7 of 24
ADT7320
Preliminary Technical Data
0.30
160
140
IDD CONTINUOUS CONVERSION
0.25
TEMPERATURE (°C)
120
0.15
0.10
60
3.0
3.5
4.0
4.5
5.0
5.5
6.0
SUPPLY VOLTAGE (V)
09012-008
20
0
2.5
Figure 8. Average Operating Supply Current vs. Supply Voltage at 25°C
8
7
6
5
4
3
2
1
0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
SUPPLY VOLTAGE (V)
6.0
09012-009
SHUTDOWN IDD (µA)
80
40
IDD 1SPS
0.05
100
Figure 9. Shutdown Current vs. Supply Voltage at 25°C
Rev. PrA | Page 8 of 24
0
0
5
10
15
20
25
30
TIME (Seconds)
Figure 10. Response to Thermal Shock
35
40
09012-011
IDD (mA)
0.20
Preliminary Technical Data
ADT7320
THEORY OF OPERATION
CIRCUIT INFORMATION
Σ-Δ MODULATOR
The on-board temperature sensor has excellent accuracy and
linearity over the entire rated temperature range without
needing correction or calibration by the user.
The sensor output is digitized by a Σ-Δ modulator, also known
as the charge balance type ADC. This type of converter uses
time-domain oversampling and a high accuracy comparator to
deliver 16 bits of resolution in an extremely compact circuit.
Configuration register functions consist of the following:
•
•
•
•
•
•
Switching between 13-bit and 16-bit resolution
Switching between normal operation and full power-down
Switching between comparator and interrupt event modes
on the INT and CT pins
Setting the active polarity of the CT and INT pins
Setting the number of faults that activate CT and INT
Enabling the standard one-shot mode and 1 SPS mode
CONVERTER DETAILS
The Σ-Δ modulator consists of an input sampler, a summing
network, an integrator, a comparator, and a 1-bit DAC. This
architecture creates a negative feedback loop and minimizes the
integrator output by changing the duty cycle of the comparator
output in response to the input voltage changes. The comparator
samples the output of the integrator at a much higher rate than
the input sampling frequency. This oversampling spreads the
quantization noise over a much wider band than that of the input
signal, improving overall noise performance and increasing
accuracy.
The modulated output of the comparator is encoded using a
circuit technique that results in SPI temperature data.
INTEGRATOR
COMPARATOR
VOLTAGE REF
AND VPTAT
1-BIT
DAC
1-BIT
CLOCK
GENERATOR
LPF DIGITAL
FILTER
13-BIT
TEMPERATURE
VALUE
REGISTER
09012-012
The ADT7320 is a 13-bit digital temperature sensor that is
extendable to 16 bits for greater resolution. An on-board
temperature sensor generates a voltage proportional to absolute
temperature, which is compared to an internal voltage reference
and input to a precision digital modulator.
Figure 11. Σ-∆ Modulator
TEMPERATURE MEASUREMENT
In normal mode, the ADT7320 runs an automatic conversion
sequence. During this automatic conversion sequence, a
conversion takes 240 ms to complete and the ADT7320 is
continuously converting. This means that as soon as one
temperature conversion is completed, another temperature
conversion begins. Each temperature conversion result is
stored in the temperature value register and is available
through the SPI interface. In continuous conversion mode,
the read operation provides the most recent converted result.
At power-up, the first conversion is a fast conversion, taking
typically 6 ms. If the temperature exceeds 147°C, the CT pin
asserts low. If the temperature exceeds 64°C, the INT pin asserts
low. Fast conversion temperature accuracy is typically within ±5°C.
The conversion clock for the part is generated internally. No
external clock is required except when reading from and writing
to the serial port.
The measured temperature value is compared with a critical
temperature limit (stored in the 16-bit TCRIT setpoint read/write
register), a high temperature limit (stored in the 16-bit THIGH
setpoint read/write register), and a low temperature limit (stored
in the 16-bit TLOW setpoint read/write register). If the measured
value exceeds these limits, the INT pin is activated; and if it exceeds
the TCRIT limit, the CT pin is activated. The INT and CT pins are
programmable for polarity via the configuration register, and
the INT and CT pins are also programmable for interrupt mode
via the configuration register.
Rev. PrA | Page 9 of 24
ADT7320
Preliminary Technical Data
CS
0x08
DIN
0x20
WAIT 240ms MINIMUM
FOR CONVERSION TO FINISH
DATA
09012-026
DOUT
SCLK
Figure 12. Typical SPI One-Shot Write to Configuration Register Followed by a Read from the Temperature Value Register
ONE-SHOT MODE
1 SPS MODE
Setting Bit 5 to 0 and Bit 6 to 1 of the configuration register
(Register Address 0x01) enables the one-shot mode. When
this mode is enabled, the ADT7320 immediately completes a
conversion and then goes into shutdown mode.
In this mode, the part performs one measurement per second.
A conversion takes only 60 ms, and it remains in the idle state
for the remaining 940 ms period. This mode is enabled by
writing 1 to Bit 5 and 0 to Bit 6 of the configuration register
(Register Address 0x01).
Wait for a minimum of 240 ms after writing to the one-shot
bits before reading back the temperature from the temperature
value register. This time ensures that the ADT7320 has time to
power up and complete a conversion.
The one-shot mode is useful when one of the circuit design
priorities is to reduce power consumption.
Rev. PrA | Page 10 of 24
Preliminary Technical Data
ADT7320
CT and INT Operation in One-Shot Mode
See Figure 13 for more information on one-shot CT pin
operation for TCRIT overtemperature events when one of the
limits is exceeded. Note that in interrupt mode, a read from
any register resets the INT and CT pins.
For the INT pin in comparator mode, if the temperature drops
below the THIGH − THYST value or goes above the TLOW + THYST
value, a write to the one-shot bits (Bit 5 and Bit 6 of the
configuration register, Register Address 0x01) resets the INT pin.
For the CT pin in the comparator mode, if the temperature drops
below the TCRIT − THYST value, a write to the one-shot bits (Bit 5
and Bit 6 of the configuration register, Register Address 0x01)
resets the CT pin, see Figure 13.
Note that when using one-shot mode, ensure that the refresh
rate is appropriate to the application being used.
TEMPERATURE
149°C
148°C
TCRIT
147°C
146°C
145°C
144°C
143°C
TCRIT – THYST
142°C
141°C
140°C
CT PIN
POLARITY = ACTIVE LOW
CT PIN
POLARITY = ACTIVE HIGH
TIME
WRITE TO
BIT 5 AND BIT 6 OF
CONFIGURATION
REGISTER.*
WRITE TO
BIT 5 AND BIT 6 OF
CONFIGURATION
REGISTER.*
*THERE IS A 240ms DELAY BETWEEN WRITING TO THE CONFIGURATION REGISTER TO START
A STANDARD ONE-SHOT CONVERSION AND THE CT PIN GOING ACTIVE. THIS IS DUE TO THE
CONVERSION TIME. THE DELAY IS 60ms IN THE CASE OF A ONE-SHOT CONVERSION.
Figure 13. One-Shot CT Pin
Rev. PrA | Page 11 of 24
09012-013
WRITE TO
BIT 5 AND BIT 6 OF
CONFIGURATION
REGISTER.*
ADT7320
Preliminary Technical Data
CONTINUOUS READ MODE
SHUTDOWN
When the command byte = 01010100 (0x54), the contents of
the temperature value register can be read out without requiring
repeated writes to the communications register. By sending 16
SCLK clocks to the ADT7320, the contents of the temperature
value register are output onto the DOUT pin.
The ADT7320 can be placed in shutdown mode by writing 1
to Bit 5 and 1 to Bit 6 of the configuration register (Register
Address 0x01). The ADT7320 can be taken out of shutdown
mode by writing 0 to Bit 5 and 0 to Bit 6 of the configuration
register (Register Address 0x01). The ADT7320 typically takes
1 ms (with a 0.1 μF decoupling capacitor) to come out of shutdown mode. The conversion result from the last conversion
prior to shutdown can still be read from the ADT7320 even
when it is in shutdown mode. When the part is taken out of
shutdown mode, the internal clock starts and a conversion initiates.
To exit the continuous read mode, the command byte 01010000
(0x50) must be written to the ADT7320.
While in continuous read mode, the part monitors activity
on the DIN line so that it can receive the instruction to exit
the continuous read mode. Additionally, a reset occurs if 32
consecutive 1s are seen on the DIN pin. Therefore, hold DIN
low in continuous read mode until an instruction is to be
written to the device.
In continuous read mode, the temperature value register cannot
be read when a conversion is taking place. If an attempt is made
to read the temperature value register while a conversion is taking
place, then all 0s are read. This is because the continuous read
mode blocks read access to the temperature value register during a
conversion.
FAULT QUEUE
Bit 0 and Bit 1 of the configuration register (Register Address 0x01)
are used to set up a fault queue. Up to four faults are provided to
prevent false tripping of the INT and CT pins when the ADT7320
is used in a noisy temperature environment. The number of
faults set in the queue must occur consecutively to set the INT
and CT outputs. For example, if the number of faults set in the
queue is four, then four consecutive temperature conversions
must occur, with each result exceeding a temperature limit in
any of the limit registers, before the INT and CT pins are activated.
If two consecutive temperature conversions exceed a temperature
limit and the third conversion does not, the fault count is reset to 0.
CS
DIN
DOUT
0x54
TEMPERATURE
VALUE
TEMPERATURE
VALUE
09012-027
SCLK
TEMPERATURE
VALUE
Figure 14. Continuous Read Mode
Rev. PrA | Page 12 of 24
Preliminary Technical Data
ADT7320
TEMPERATURE DATA FORMAT
TEMPERATURE CONVERSION FORMULAS
One LSB of the ADC corresponds to 0.0625°C in 13-bit mode.
The ADC can theoretically measure a temperature range of 255°C,
but the ADT7320 is guaranteed to measure a low value temperature
limit of −40°C to a high value temperature limit of +150°C. The
temperature measurement result is stored in the 16-bit temperature
value register and is compared with the high temperature limits
stored in the TCRIT setpoint register and the THIGH setpoint register. It
is also compared with the low temperature limit stored in the TLOW
setpoint register.
16-Bit Temperature Data Format
Temperature data in the temperature value register, the TCRIT
setpoint register, the THIGH setpoint register, and the TLOW
setpoint register are represented by a 13-bit, twos complement
word. The MSB is the temperature sign bit. The three LSBs,
Bit 0 to Bit 2, on power-up, are not part of the temperature
conversion result and are flag bits for TCRIT, THIGH, and TLOW.
Table 5 shows the 13-bit temperature data format without
Bit 0 to Bit 2.
The number of bits in the temperature data-word can be extended
to 16 bits, twos complement by setting Bit 7 to 1 in the configuration
register (Register Address 0x01). When using a 16-bit temperature
data value, Bit 0 to Bit 2 are not used as flag bits and are instead
the LSB bits of the temperature value. The power-on default
setting has a 13-bit temperature data value.
Reading back the temperature from the temperature value register
requires a 2-byte read. Designers that use a 9-bit temperature
data format can still use the ADT7320 by ignoring the last four
LSBs of the 13-bit temperature value. These four LSBs are Bit 3
to Bit 6 in Table 5.
Digital Output
(Binary) Bits[15:3]
1 1101 1000 0000
1 1110 0111 0000
1 1111 1111 1111
0 0000 0000 0000
0 0000 0000 0001
0 0001 1001 0000
0 0110 1001 0000
0 0111 1101 0000
0 1001 0110 0000
Negative Temperature = (ADC Code(dec) − 65,536)/128
where ADC Code uses all 16 bits of the data byte, including the
sign bit.
Negative Temperature = (ADC Code(dec) − 32,768)/128
where the MSB is removed from the ADC code.
13-Bit Temperature Data Format
Positive Temperature = ADC Code(dec)/16
Negative Temperature = (ADC Code(dec) − 8192)/16
where ADC Code uses all 13 bits of the data byte, including the
sign bit.
Negative Temperature = (ADC Code(dec) − 4096)/16
where the MSB is removed from the ADC code.
10-Bit Temperature Data Format
Positive Temperature = ADC Code(dec)/2
Negative Temperature = (ADC Code(dec) − 1024)/2
where ADC Code uses all 10 bits of the data byte, including the
sign bit.
Negative Temperature = (ADC Code(dec) − 512)/2
where the MSB is removed from the ADC Code.
9-Bit Temperature Data Format
Positive Temperature = ADC Code(dec)
Table 5. 13-Bit Temperature Data Format
Temperature
−40°C
−25°C
−0.0625°C
0°C
+0.0625°C
+25°C
+105°C
+125°C
+150°C
Positive Temperature = ADC Code(dec)/128
Digital
Output (Hex)
0x1D80
0x1E70
0x1FFF
0x000
0x001
0x190
0x690
0x7D0
0x960
Negative Temperature = ADC Code(dec) − 512
where ADC Code uses all nine bits of the data byte, including
the sign bit.
Negative Temperature = ADC Code(dec) − 256
where the MSB is removed from the ADC Code.
Rev. PrA | Page 13 of 24
ADT7320
Preliminary Technical Data
REGISTERS
The ADT7320 contains eight registers:
STATUS REGISTER
•
•
•
•
This 8-bit read-only register (Register Address 0x00) reflects the
status of the overtemperature and undertemperature interrupts
that can cause the CT and INT pins to go active. It also reflects
the status of a temperature conversion operation. The interrupt
flags in this register are reset by a read operation to the status
register and/or when the temperature value returns within the
temperature limits including hysteresis. The RDY bit is reset after a
read from the temperature value register. In one-shot and 1 SPS
modes, the RDY bit is reset after a write to the one-shot bits.
A status register
A configuration register
Five temperature registers
An ID register
The status register, temperature value register, and the ID
register are read-only.
Table 6. ADT7320 Registers
Register Address
0x00
0x01
0x02
0x03
0x04
0x05
0x06
0x07
Description
Status
Configuration
Temperature value
ID
TCRIT setpoint
THYST setpoint
THIGH setpoint
TLOW setpoint
Power-On Default
0x80
0x00
0x0000
0xCX
0x4980 (147°C)
0x05 (5°C)
0x2000 (64°C)
0x0500 (10°C)
Table 7. Status Register (Register Address 0x00)
Bit(s)
[0:3]
[4]
Default Value
0000
0
Type
R
R
Name
Unused
TLOW
[5]
0
R
THIGH
[6]
0
R
TCRIT
[7]
1
R
RDY
Description
Reads back 0.
This bit is set to 1 when the temperature goes below the TLOW temperature limit. This bit
clears to 0 when the status register is read and/or when the temperature measured goes
back above the limit set in the TLOW + THYST setpoint registers.
This bit is set to 1 when the temperature goes above the THIGH temperature limit. This bit
clears to 0 when the status register is read and/or when the temperature measured goes
back below the limit set in the THIGH − THYST setpoint registers.
This bit is set to 1 when the temperature goes above the TCRIT temperature limit. This bit
clears to 0 when the status register is read and/or when the temperature measured goes
back below the limit set in the TCRIT − THYST setpoint registers.
This bit goes low when the temperature conversion result is written into the temperature
value register. It is reset to 1 when the temperature value register is read. In one-shot and
1 SPS modes, this bit is reset after a write to the one-shot bits.
Rev. PrA | Page 14 of 24
Preliminary Technical Data
ADT7320
CONFIGURATION REGISTER
This 8-bit read/write register stores various configuration modes
for the ADT7320, including shutdown, overtemperature and
undertemperature interrupts, one-shot, continuous conversion,
interrupt pins polarity, and overtemperature fault queues.
Table 8. Configuration Register (Register Address 0x01)
Bit
[0:1]
Default
Value
00
Type
R/W
Name
Fault queue
[2]
0
R/W
CT pin polarity
[3]
0
R/W
INT pin polarity
[4]
0
R/W
INT/CT mode
[5:6]
00
R/W
Operation mode
[7]
0
R/W
Resolution
Description
These two bits set the number of undertemperature/overtemperature faults that can
occur before setting the INT and CT pins. This helps to avoid false triggering due to
temperature noise.
00 = 1 fault (default).
01 = 2 faults.
10 = 3 faults.
11 = 4 faults.
This bit selects the output polarity of the CT pin.
0 = active low.
1 = active high.
This bit selects the output polarity of the INT pin.
0 = active low.
1 = active high.
This bit selects between comparator mode and interrupt mode.
0 = interrupt mode.
1 = comparator mode.
These two bits set the operational mode for the ADT7320.
00 = continuous conversion (default). When one conversion is finished, the ADT7320
starts another.
01 = one shot. Conversion time is typically 240 ms.
10 = 1 SPS mode. Conversion time is typically 60 ms. This operational mode reduces the
average current consumption.
11 = shutdown. All circuitry except interface circuitry is powered down.
This bit sets up the resolution of the ADC when converting.
0 = 13-bit resolution. Sign bit + 12 bits gives a temperature resolution of 0.0625°C.
1 = 16-bit resolution. Sign bit + 15 bits gives a temperature resolution of 0.0078125°C.
Rev. PrA | Page 15 of 24
ADT7320
Preliminary Technical Data
TEMPERATURE VALUE REGISTER
ID REGISTER
The temperature value register stores the temperature measured
by the internal temperature sensor. The temperature is stored as
a 16-bit twos complement format. The temperature is read back
from the temperature value register (Register Address 0x02) as a
16-bit value.
This 8-bit read-only register (Register Address 0x03) stores
the manufacturer ID in Bit 7 to Bit 3 and the silicon revision in
Bit 2 to Bit 0.
Bit 2, Bit 1, and Bit 0 are event alarm flags for TCRIT, THIGH, and
TLOW. When the ADC is configured to convert the temperature
to a 16-bit digital value, Bit 2, Bit 1, and Bit 0 are no longer used
as flag bits and are, instead, used as the LSB bits for the extended
digital value.
TCRIT SETPOINT REGISTER
The 16-bit TCRIT setpoint register (Register Address 0x04) stores
the critical overtemperature limit value. A critical overtemperature
event occurs when the temperature value stored in the temperature
value register exceeds the value stored in this register. The CT
pin is activated if a critical overtemperature event occurs. The
temperature is stored in twos complement format with the MSB
being the temperature sign bit.
The default setting for the TCRIT setpoint is 147°C.
Table 9. Temperature Value Register (Register Address 0x02)
Bit
[0]
Default Value
0
Type
R
Name
TLOW flag/LSB0
[1]
0
R
THIGH flag/LSB1
[2]
0
R
TCRIT flag/LSB2
[3:7]
[8:14]
[15]
00000
0000000
0
R
R
R
Temp
Temp
Sign
Description
Flags a TLOW event if the configuration register, Register Address 0x01[7] = 0
(13-bit resolution). When the temperature value is below TLOW,, this bit it set to 1.
Contains the Least Significant Bit 0 of the 15-bit temperature value if the
configuration register, Register Address 0x01[7] = 1 (16-bit resolution).
Flags a THIGH event if the configuration register, Register Address 0x01[7] = 0
(13-bit resolution). When the temperature value is above THIGH, this bit it set to 1.
Contains the Least Significant Bit 1 of the 15-bit temperature value if the
configuration register, Register Address 0x01[7] = 1 (16-bit resolution).
Flags a TCRIT event if the configuration register, Register Address 0x01[7] = 0
(13-bit resolution). When the temperature value exceeds TCRIT, this bit it set to 1.
Contains the Least Significant Bit 2 of the 15-bit temperature value if the
configuration register, Register Address 0x01[7] = 1 (16-bit resolution).
Temperature value in twos complement format.
Temperature value in twos complement format.
Sign bit, indicates if the temperature value is negative or positive.
Table 10. ID Register (Register Address 0x03)
Bit
[2:0]
[7:3]
Default Value
XXX
11000
Type
R
R
Name
Revision ID
Manufacture ID
Description
Contains the silicon revision identification number.
Contains the manufacturer identification number.
Table 11. TCRIT Setpoint Register (Register Address 0x04)
Bit
[15:0]
Default Value
0x4980
Type
R/W
Name
TCRIT
Description
16-bit critical overtemperature limit, stored in twos complement format.
Rev. PrA | Page 16 of 24
Preliminary Technical Data
ADT7320
THYST SETPOINT REGISTER
TLOW SETPOINT REGISTER
The THYST setpoint 8-bit register (Register Address 0x05) stores
the temperature hysteresis value for the THIGH, TLOW, and TCRIT
temperature limits. The temperature hysteresis value is stored in
straight binary format using four LSBs. Increments are possible
in steps of 1°C from 0°C to 15°C. The value in this register is
subtracted from the THIGH and TCRIT values and added to the
TLOW value to implement hysteresis.
The 16-bit TLOW setpoint register (Register Address 0x07) stores
the undertemperature limit value. An undertemperature event
occurs when the temperature value stored in the temperature
value register is less than the value stored in this register. The
INT pin is activated if an undertemperature event occurs. The
temperature is stored in twos complement format with the MSB
being the temperature sign bit.
The default setting for the THYST setpoint is 5°C.
The default setting for the TLOW setpoint is 10°C.
THIGH SETPOINT REGISTER
The 16-bit THIGH setpoint register (Register Address 0x06) stores
the overtemperature limit value. An overtemperature event occurs
when the temperature value stored in the temperature value
register exceeds the value stored in this register. The INT pin is
activated if an overtemperature event occurs. The temperature
is stored in twos complement format with the most significant
bit being the temperature sign bit.
The default setting for the THIGH setpoint is 64°C.
Table 12. THYST Setpoint Register (Register Address 0x05)
Bit
[0:3]
Default Value
0101
Type
R/W
Name
THYST
Description
Hysteresis value, from 0°C to 15°C. Stored in straight binary format. The default setting is 5°C.
[4:7]
0000
R/W
N/A
Not used.
Table 13. THIGH Setpoint Register (Register Address 0x06)
Bit
[0:15]
Default Value
0x2000
Type
R/W
Name
THIGH
Description
16-bit overtemperature limit, stored in twos complement format.
Table 14. TLOW Setpoint Register (Register Address 0x07)
Bit
[0:15]
Default Value
0x0500
Type
R/W
Name
TLOW
Description
16-bit undertemperature limit, stored in twos complement format.
Rev. PrA | Page 17 of 24
ADT7320
Preliminary Technical Data
SERIAL INTERFACE
PULL-UP
VDD
VDD
VDD
ADT7320
SCLK
DOUT
DIN
CS
10kΩ
GND
CT
INT
09012-014
MICROCONTROLLER
10kΩ
0.1µF
Figure 15. Typical SPI Interface Connection
The ADT7320 has a 4-wire serial peripheral interface (SPI). The
interface has a data input pin (DIN) for inputting data to the device,
a data output pin (DOUT) for reading data back from the device,
and a data clock pin (SCLK) for clocking data into and out of
the device. A chip select pin (CS) enables or disables the serial
interface. CS is required for correct operation of the interface.
Data is clocked out of the ADT7320 on the negative edge of SCLK,
and data is clocked into the device on the positive edge of SCLK.
SPI COMMAND BYTE
All data transactions on the bus begin with the master taking
CS from high to low and sending out the command byte. This
indicates to the ADT7320 whether the transaction is a read or a
write and provides the address of the register for the data transfer.
Table 15 shows the command byte.
Bit C7 of the command byte must be set to 0 to successfully begin a
bus transaction. The SPI interface does not work correctly if a 1
is written into this bit.
Bit C6 is the read/write bit; 1 indicates a read, and 0 indicates a write.
Bits[C5:C3] contain the target register address. One register can
be read from or written to per bus transaction.
Bit C2 activates a continuous read mode on the temperature value
register only. When this bit is set, the serial interface is configured
so that the temperature value register can be continuously read.
When the command word is 01010100 (0x54), the contents of
the temperature value register can be read out without requiring
repeated writes to set the address bits. Simply sending 16 SCLK
clocks to the ADT7320 clocks the contents of the temperature
value register onto the DOUT pin.
Table 15. Command Byte
C7
0
C6
R/W
C5
C4
C3
Register address
C2
Continuous read
C1
0
C0
0
Rev. PrA | Page 18 of 24
Preliminary Technical Data
ADT7320
Figure 16 shows a write to an 8-bit register, and Figure 17 shows
a write to a 16-bit register.
WRITING DATA
Data is written to the ADT7320 in eight bits or 16 bits, depending
on the addressed register. The first byte written to the device is
the command byte, with the read/write bit set to 0. The master
then supplies the 8-bit or 16-bit input data on the DIN line. The
ADT7320 clocks the data into the register addressed in the
command byte on the positive edge of SCLK. The master
finishes the write by pulling CS high.
The master must begin a new write transaction on the bus for
every register write. Only one register is written to per bus
transaction.
CS
1
2
3
4
5
6
7
8
9
10
11
DIN
0
R/W
C6
REGISTER ADDR
CONT
READ
0
0
C4
C2
C1
C0
C5
C3
13
14
15
16
8-BIT DATA
8-BIT COMMAND BYTE
C7
12
D7
D6
D5
D4
D3
D2
D1
09012-028
SCLK
D0
Figure 16. Writing to an 8-Bit Register
CS
1
2
3
4
5
6
7
8
9
10
11
12
13
14
DIN
0
R/W
REGISTER ADDR
C6
C5
C4
C3
16
17
22
23
24
16-BIT DATA
8-BIT COMMAND BYTE
C7
15
CONT
READ
0
0
C2
C1
C0
D15
D14
D13
D12
D11
D10
Figure 17. Writing to a 16-Bit Register
Rev. PrA | Page 19 of 24
D9
D8
D7
D2
D1
D0
09012-029
SCLK
ADT7320
Preliminary Technical Data
CS
SCLK
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
8-BIT COMMAND WORD
0
DIN
C7
R/W
REGISTER ADDR
C6
C4
C5
C3
CONT
READ
0
0
C2
C1
C0
D7
DOUT
D6
D5
D4
D3
D2
D1
09012-030
8-BIT DATA
D0
Figure 18. Read from an 8-Bit Register
CS
SCLK
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
22
23
24
8-BIT COMMAND BYTE
DIN
0
R/W
C7
C6
CONT
REGISTER ADDR READ
C5
C4
C3
C2
0
0
C1
C0
DOUT
D15
D14
D13
D12
D11
D10
D9
D8
D7
D2
D1
D0
09012-031
16-BIT DATA
Figure 19. Read from a 16-Bit Register
READING DATA
INTERFACING TO DSPs OR MICROCONTROLLERS
A read transaction begins when the master writes the command
byte to the ADT7320 with the read/write bit set to 1. The master
then supplies 8 or 16 clock pulses, depending on the addressed
register, and the ADT7320 clocks out data from the addressed
register on the DOUT line. Data is clocked out on the first
falling edge of SCLK following the command byte.
The ADT7320 can be operated with CS used as a frame synchronization signal. This scheme is useful for DSP interfaces.
In this case, the first bit (MSB) is effectively clocked out by CS
because CS normally occurs after the falling edge of SCLK in
DSPs. SCLK can continue to run between data transfers,
provided that the timing numbers are obeyed.
The read transaction finishes when the master takes CS high.
CS can be tied to ground and the serial interface can operate in
a 3-wire mode. DIN, DOUT, and SCLK are used to communicate
with the ADT7320 in this mode.
The master must begin a new read transaction on the bus for
every register read. Only one register is read per bus transaction.
However, in continuous read mode, Command Byte C2 = 1 and
the temperature value register can be read from continuously.
The master sends 16 clock pulses on SCLK, and the temperature
value is clocked out on DOUT. See Figure 18 and Figure 19.
For microcontroller interfaces, it is recommended that SCLK
idle high between data transfers.
SERIAL INTERFACE RESET
The serial interface can be reset by writing a series of 1s on the DIN
input. If a Logic 1 is written to the ADT7320 line for at least 32 serial
clock cycles, the serial interface is reset. This ensures that the interface
can be reset to a known state if the interface gets lost due to a software
error or some glitch in the system. Reset returns the interface to
the state in which it is expecting a write to the communications
register. This operation resets the contents of all registers to their
power-on values. Following a reset, the user should allow a period
of 500 μs before addressing the serial interface.
Rev. PrA | Page 20 of 24
Preliminary Technical Data
ADT7320
INT AND CT OUTPUTS
Comparator Mode
The INT and CT pins are open drain outputs, and both pins
require a 10 kΩ pull-up resistor to VDD.
In comparator mode, the INT pin returns to its inactive status
when the temperature drops below the THIGH − THYST limit or
rises above the TLOW + THYST limit.
UNDERTEMPERATURE AND OVERTEMPERATURE
DETECTION
Putting the ADT7320 into shutdown mode does not reset the
INT state in comparator mode.
The INT and CT pins have two undertemperature/overtemperature
modes: comparator mode and interrupt mode. The interrupt
mode is the default power-up overtemperature mode. The INT
output pin becomes active when the temperature is greater than
the temperature stored in the THIGH setpoint register or less than
the temperature stored in the TLOW setpoint register. How this
pin reacts after this event depends on the overtemperature
mode selected.
Interrupt Mode
In interrupt mode, the INT pin goes inactive when any ADT7320
register is read. When the INT pin is reset, it goes active again
only when the temperature is greater than the temperature stored
in the THIGH setpoint register or less than the temperature stored
in the TLOW setpoint register.
Figure 20 illustrates the comparator and interrupt modes for
events exceeding the THIGH limit with both pin polarity settings.
Figure 21 illustrates the comparator and interrupt modes for
events exceeding the TLOW limit with both pin polarity settings.
Placing the ADT7320 into shutdown mode resets the INT pin
in interrupt mode.
TEMPERATURE
82°C
81°C
THIGH
80°C
79°C
78°C
77°C
76°C
THIGH – THYST
75°C
74°C
73°C
INT PIN
(COMPARATOR MODE)
POLARITY = ACTIVE LOW
INT PIN
(INTERRUPT MODE)
POLARITY = ACTIVE LOW
INT PIN
(COMPARATOR MODE)
POLARITY = ACTIVE HIGH
TIME
READ
READ
READ
Figure 20. INT Output Temperature Response Diagram for THIGH Overtemperature Events
Rev. PrA | Page 21 of 24
09012-020
INT PIN
(INTERRUPT MODE)
POLARITY = ACTIVE HIGH
ADT7320
Preliminary Technical Data
TEMPERATURE
–13°C
–14°C
TLOW + THYST
–15°C
–16°C
–17°C
–18°C
–19°C
TLOW
–20°C
–21°C
–22°C
INT PIN
(COMPARATOR MODE)
POLARITY = ACTIVE LOW
INT PIN
(INTERRUPT MODE)
POLARITY = ACTIVE LOW
INT PIN
(COMPARATOR MODE)
POLARITY = ACTIVE HIGH
TIME
READ
READ
READ
09012-021
INT PIN
(INTERRUPT MODE)
POLARITY = ACTIVE HIGH
Figure 21. INT Output Temperature Response Diagram for TLOW Undertemperature Events
Rev. PrA | Page 22 of 24
Preliminary Technical Data
ADT7320
APPLICATIONS INFORMATION
THERMAL RESPONSE TIME
TEMPERATURE MONITORING
The time required for a temperature sensor to settle to a specified
accuracy is a function of the thermal mass of the sensor and the
thermal conductivity between the sensor and the object being sensed.
Thermal mass is often considered equivalent to capacitance.
Thermal conductivity is commonly specified using the symbol,
Q, and can be thought of as thermal resistance. It is commonly
specified in units of degrees per watt of power transferred across
the thermal joint. The time required for the part to settle to the
desired accuracy is dependent on the thermal contact established
in that particular application and the equivalent power of the
heat source. In most applications, the settling time is best
determined empirically.
The ADT7320 is ideal for monitoring the thermal environment
within hazardous automotive applications. The die accurately reflects
the exact thermal conditions that affect nearby integrated circuits.
SUPPLY DECOUPLING
The ADT7320 should be decoupled with a 0.1 μF ceramic capacitor
between VDD and GND. This is particularly important when the
ADT7320 is mounted remotely from the power supply. Precision
analog products, such as the ADT7320, require a well-filtered
power source.
The ADT7320 measures and converts the temperature at the
surface of its own semiconductor chip. When the ADT7320 is
used to measure the temperature of a nearby heat source, the
thermal impedance between the heat source and the ADT7320
must be considered.
When the thermal impedance is determined, the temperature of
the heat source can be inferred from the ADT7320 output. As
much as 60% of the heat transferred from the heat source to the
thermal sensor on the ADT7320 die is discharged via the copper
tracks and the bond pads. Of the pads on the ADT7320, the
GND pad transfers most of the heat. Therefore, to measure the
temperature of a heat source, it is recommended that the thermal
resistance between the ADT7320 GND pad and the GND of the
heat source be reduced as much as possible.
Because the ADT7320 operates from a single supply, it may
seem convenient to tap into the digital logic power supply.
Unfortunately, the logic supply is often a switch-mode design,
which generates noise in the 20 kHz to 1 MHz range. In addition,
fast logic gates can generate glitches hundreds of millivolts in
amplitude due to wiring resistance and inductance.
If possible, the ADT7320 should be powered directly from the
system power supply. This arrangement, shown in Figure 22,
isolates the analog section from the logic-switching transients.
Even if a separate power supply trace is not available, generous
supply bypassing reduces supply-line induced errors. Local supply
bypassing consisting of a 0.1 μF ceramic capacitor is critical for
the temperature accuracy specifications to be achieved. This
decoupling capacitor must be placed as close as possible to the
VDD pin of the ADT7320.
0.1µF
ADT7320
POWER
SUPPLY
09012-022
TTL/CMOS
LOGIC
CIRCUITS
Figure 22. Use of Separate Traces to Reduce Power Supply Noise
Rev. PrA | Page 23 of 24
ADT7320
Preliminary Technical Data
OUTLINE DIMENSIONS
PIN 1
INDICATOR
4.10
4.00 SQ
3.90
0.35
0.30
0.25
0.65
BSC
16
13
PIN 1
INDICATOR
12
1
EXPOSED
PAD
4
2.70
2.60 SQ
2.50
9
0.80
0.75
0.70
0.45
0.40
0.35
8
BOTTOM VIEW
0.05 MAX
0.02 NOM
COPLANARITY
0.08
0.20 REF
SEATING
PLANE
0.25 MIN
FOR PROPER CONNECTION OF
THE EXPOSED PAD, REFER TO
THE PIN CONFIGURATION AND
FUNCTION DESCRIPTIONS
SECTION OF THIS DATA SHEET.
012909-B
TOP VIEW
5
COMPLIANT TO JEDEC STANDARDS MO-220-WGGC.
Figure 23. 16-Lead Lead Frame Chip Scale Package [LFCSP_WQ]
4 mm × 4 mm Body, Very Very Thin Quad
(CP-16-17)
Dimensions shown in millimeters
ORDERING GUIDE
Model1
ADT7320UCPZ
ADT7320UCPZ-R2
ADT7320UCPZ-RL7
EVAL-ADT7X20EBZ
1
2
Temperature Range
−40°C to +150°C
−40°C to +150°C
−40°C to +150°C
Temperature Accuracy2
±0.25°C
±0.25°C
±0.25°C
Z = RoHS Compliant Part.
Maximum accuracy over the −20°C to +105°C temperature range.
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PR09012-0-6/10(PrA)
Rev. PrA | Page 24 of 24
Package Description
16-lead LFCSP_WQ
16-Lead LFCSP_WQ
16-Lead LFCSP_WQ
Evaluation Board
Package Option
CP-16-17
CP-16-17
CP-16-17