±1°C Accurate, 13-Bit,
FEATURES
13-bit temperature-to-digital converter
−40°C to +150°C operating temperature range
±0.5°C typical accuracy
0.03125°C temperature resolution
Shutdown current of 1 μA
Power dissipation of 0.631 mW at V
SPI- and DSP-compatible serial interface
Shutdown mode
Space-saving SOT-23 and MSOP packages
Compatible with AD7814
APPLICATIONS
Medical equipment
Automotive
Environmental controls
Oil temperature
Hydraulic systems
Cellular phones
Hard disk drives
Personal computers
Electronic test equipment
Office equipment
Domestic appliances
Process control
GENERAL DESCRIPTION
The ADT7301 is a complete temperature monitoring system
available in SOT-23 and MSOP packages. It contains a band gap
temperature sensor and a 13-bit ADC to monitor and digitize
the temperature reading to a resolution of 0.03125°C.
The ADT7301 has a flexible serial interface that allows easy
interfacing to most microcontrollers. The interface is compati-
ble with SPI
DSPs. The part features a standby mode that is controlled via
the serial interface. The ADT7301’s wide supply voltage range,
low supply current, and SPI-compatible interface make it ideal
for a variety of applications including personal computers,
office equipment, automotive, and domestic appliances. The
ADT7301 is rated for operation over the −40°C to +150°C
temperature range. It is not recommended to operate the device
at temperatures above +125°C for greater than a total of 5%
(5,000 hours) of the lifetime of the device. Exposure beyond this
limit affects device reliability.
®, QSPI™, and MICROWIRE™ protocols as well as
= 3.3 V
DD
Digital Temperature Sensor
ADT7301
FUNCTIONAL BLOCK DIAGRAM
BAND GAP
TEMPERATURE
SENSOR
GND
ADT7301
INTERFACE
PRODUCT HIGHLIGHTS
1. On-chip temperature sensor that allows an accurate
measurement of the ambient temperature. The measurable
temperature range is −40°C to +150°C.
2. Supply voltage of 2.7 V to 5.25 V.
3. Space-saving 6-lead SOT-23 and 8-lead MSOP packages.
4. Typical temperature accuracy of ±0.5°C.
5. 13-bit temperature reading to 0.03125°C resolution.
6. Shutdown mode that reduces the power consumption to
4.88 μW with V
7. Compatible with AD7814.
= 3.3 V @ 1 SPS.
DD
13-BIT
ANALOG/DIGITAL
CONVERTER
TEMPERATURE
VALUE
REGISTER
SERIAL
BUS
Figure 1.
V
DD
CS
SCLK
DIN
DOUT
02884-0-001
Rev. 0
Information furnished by Analog Devices is believed to be accurate and reliable.
However, no responsibility is assumed by Analog Devices for its use, nor for any
infringements of patents or other rights of third parties that may result from its use.
Specifications subject to change without notice. No license is granted by implication
or otherwise under any patent or patent rights of Analog Devices. Trademarks and
registered trademarks are the property of their respective owners.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700 www.analog.com
Fax: 781.461.3113 © 2005 Analog Devices, Inc. All rights reserved.
ADT7301
TABLE OF CONTENTS
Specifications..................................................................................... 3
Temperature Value Register...................................................... 10
Timing Characteristics ................................................................ 4
Absolute Maximum Ratings............................................................ 5
ESD Caution.................................................................................. 5
Pin Configurations and Function Descriptions ........................... 6
Typical Performance Characteristics ............................................. 7
Theory of Operation ........................................................................ 9
Converter Details.......................................................................... 9
REVISION HISTORY
10/05—Revision 0: Initial Version
Serial Interface............................................................................ 11
Applications..................................................................................... 12
Microprocessor Interfacing....................................................... 12
Mounting the ADT7301............................................................ 14
Supply Decoupling..................................................................... 14
Outline Dimensions....................................................................... 15
Ordering Guide .......................................................................... 15
Rev. 0 | Page 2 of 16
ADT7301
SPECIFICATIONS
TA = T
Table 1. A Grade Specifications
Parameter Min Typ Max Unit Test Conditions/Comments
TEMPERATURE SENSOR AND ADC VDD = 3.3 V (±10%) and 5 V (±5%)
±2 °C T
±3 °C T
±42°C TA = −40°C to +150°C
SUPPLIES
190 300 μA VDD = 3.3 V, powered up and not converting
1.6 2.2 mA VDD = 5 V, powered up and converting
280 400 μA VDD = 5 V, powered up and not converting
0.4 2 μA VDD = 5 V, TA = 0°C to 70°C
20 μA VDD = 2.7 V to 5.25 V, TA = –40°C to +150°C
7.4 μW VDD = 5 V
65 μW VDD = 5 V
641 μW VDD = 5 V
DIGITAL INPUT
DIGITAL OUTPUT
1
The accuracy specifications for 0°C to 70°C are specified to 3.5-Σ performance.
2
It is not recommended to operate the device at temperatures above 125°C for greater than a total of 5% (5,000 hours) of the lifetime of the device. Any exposure
beyond this limit affects device reliability.
3
The thermal time constant is the time it takes for a temperature delta to change to 63.2% of its final value. For example, if the ADT7301 experiences a thermal shock
from 0°C to 100°C, it would take typically two seconds for the ADT7301 to reach 63.2°C.
4
The ADT7301 is taken out of shutdown mode and a temperature conversion is immediately performed after this write operation. Once the temperature conversion is
complete, the ADT7301 is put back into shutdown mode.
5
Guaranteed by design and characterization, not production tested.
MIN
Accuracy
to T
, VDD = 2.7 V to 5.25 V, unless otherwise noted. All specifications for –40°C to +150°C, unless otherwise noted.
MAX
1
±0.5 ±1 °C TA = 0°C to 70°C
= −20°C to +85°C
A
= −40°C to +125°C
A
Temperature Resolution 0.03125 °C
Auto Conversion Update Rate, tR 1 sec Temperature measurement every 1 second
Temperature Conversion Time 800 μs
Thermal Time Constant
3
2 sec
Supply Voltage 2.7 5.25 V For specified performance
Supply Current
Normal Mode 1.6 2.2 mA VDD = 3.3 V, powered up and converting
Shutdown Mode 0.2 1 μA VDD = 3.3 V, TA = 0°C to 70°C
Power Dissipation
Normal Mode (Average) 631 μW VDD = 3.3 V, autoconversion update, tR
1.41 mW VDD = 5 V, autoconversion update, tR
Shutdown Mode (Average)
4
1 SPS 4.88 μW VDD = 3.3 V
10 SPS 42.9 μW VDD = 3.3 V
100 SPS 423 μW VDD = 3.3 V
5
Input High Voltage, VIH 2.5 V
Input Low Voltage, VIL 0.8 V
Input Current, IIN ±1 μA V
= 0 V to VDD
IN
Input Capacitance, CIN 10 pF All digital inputs
5
Output High Voltage, VOH V
− 0.3 V I
DD
SOURCE
= I
SINK
= 200 μA
Output Low Voltage, VOL 0.4 V IOL = 200 μA
Output Capacitance, C
50 pF
OUT
Rev. 0 | Page 3 of 16
ADT7301
TIMING CHARACTERISTICS
Guaranteed by design and characterization, not production tested. 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. T
Table 2.
Parameter
1
Limit Unit Comments
t1 5 ns min
t2 25 ns min SCLK high pulse width
t3 25 ns min SCLK low pulse width
2
t4
t
5
35 ns max Data access time after SCLK falling edge
20 ns min Data set-up time prior to SCLK rising edge
t6 5 ns min Data hold time after SCLK rising edge
t7 5 ns min
2
t
8
1
See Figure 14 for the SPI timing diagram.
2
Measured with the load circuit of Figure 2.
40 ns max
= T
A
MIN
to T
, VDD = 2.7 V to 5.25 V, unless otherwise noted.
MAX
CS
to SCLK set-up time
CS
to SCLK hold time
CS
to DOUT high Impedance
I
OL
1.6V
OH
02884-0-002
TO
OUTPUT
PIN
50pF
C
L
200μA
200μAI
Figure 2. Load Circuit for Data Access Time and Bus Relinquish Time
Rev. 0 | Page 4 of 16
ADT7301
ABSOLUTE MAXIMUM RATINGS
Table 3.
Parameter Rating
VDD to GND −0.3 V to +7 V
Digital Input Voltage to GND −0.3 V to VDD + 0.3 V
Digital Output Voltage to GND −0.3 V to VDD + 0.3 V
Operating Temperature Range
1
−40°C to +150°C
Storage Temperature Range −65°C to +150°C
Junction Temperature 150°C
6-Lead SOT-23 (RT-6)
Power Dissipation
2
W
= (TJ max − T
MAX
A
3
)/θJA
Thermal Impedance
θJA, Junction-to-Ambient
190.4°C/W
(Still Air)
8-Lead MSOP (RM-8)
Power Dissipation
Thermal Impedance
2
4
θJA, Junction-to-Ambient
W
= (TJ max − T
MAX
205.9°C/W
A
3
)/θJA
(Still Air)
θJC, Junction-to-Case 43.74°C/W
IR Reflow Soldering
Peak Temperature 220°C (0°C /5°C)
Time at Peak Temperature 10 sec to 20 sec
Ramp-Up Rate 3°C/s max
Ramp-Down Rate −6°C/s max
Time 25°C to Peak Temperature 6 minutes max
IR Reflow Soldering—Pb-Free Package
Peak Temperature 260°C (0°C)
Time at Peak Temperature 20 sec to 40 sec
Ramp-Up Rate 3°C/s max
Ramp-Down Rate −6°C/s max
Time 25°C to Peak Temperature 8 minutes max
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
1.2
1.0
0.8
0.6
0.4
0.2
MAXIMUM POWER DISSIPATION (W)
0
–40
0
–10
–20
–30
Figure 3. Plot of Maximum Power Dissipation vs. Temperature
1
It is not recommended to operate the ADT7301 at temperatures above
125°C for greater than a total of 5% (5,000 hours) of the lifetime of the
device. Any exposure beyond this limit affects device reliability.
2
Values relate to the package being used on a standard 2-layer PCB. Refer
to Figure 3 for a plot of maximum power dissipation vs. ambient
temperature (TA).
3
TA = ambient temperature.
4
Junction-to-case resistance is applicable to components featuring a
preferential flow direction, for example, components mounted on a heat
sink. Junction-to-ambient resistance is more useful for air-cooled,
PCB-mounted components.
SOT-23
MSOP
50
40
30
20
10
TEMPERATURE (°C)
90
80
70
60
100
110
120
130
140
150
02884-003
ESD CAUTION
ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on the
human body and test equipment and can discharge without detection. Although this product features
proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy
electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance
degradation or loss of functionality.
Rev. 0 | Page 5 of 16
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