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±0.5°C Accurate, 10-Bit Digital
Temperature Sensors in SOT-23
AD7414/AD7415
FEATURES
10-bit temperature-to-digital converter
Temperature range: −40°C to +125°C
Typical accuracy of ±0.5°C at +40°C
SMBus/I
2
C®-compatible serial interface
3 µA power-down current
Temperature conversion time: 29 µs typ
Space-saving 6-lead (AD7414) and 5-lead (AD7415)
SOT-23 packages
Pin selectable addressing via AS
Overtemperature indicator (AD7414 Only)
SMBus alert function (AD7414 only)
4 versions allow 8 I
2
C addresses (AD7414)
2 versions allow 6 I
2
C addresses (AD7415)
GND
FUNCTIONAL BLOCK DIAGRAM
BAND GAP
TEMPERATURE
SENSOR
10-BIT
ANALOG-DIGITAL
CONVERTER
V
DD
CONFIGURATION
REGISTER
T
HIGH
SETPOINT
REGISTER
T
LOW
SETPOINT
REGISTER
TEMPERATURE
VALUE
REGISTER
SETPOINT
COMPARATOR
ALERT
AS
SMBus/I
2
C
INTERFACE
SCL
SDA
AD7414
AD7415
GND
BAND GAP
TEMPERATURE
SENSOR
10-BIT
ANALOG-DIGITAL
CONVERTER
V
DD
APPLICATIONS
Hard disk drives
Personal computers
Electronic test equipment
Office equipment
Domestic appliances
Process control
Cellular phones
CONFIGURATION
REGISTER
AS
TEMPERATURE
VALUE
REGISTER
SDA
Figure 1.
GENERAL DESCRIPTION
The AD7414/AD7415 are complete temperature monitoring
systems in 6-lead and 5-lead SOT-23 packages. They contain a
band gap temperature sensor and a 10-bit ADC to monitor and
digitize the temperature reading to a resolution of 0.25°C.
The AD7414/AD7415 provide a 2-wire serial interface that is
compatible with SMBus and I
2
C interfaces. The parts come in four
versions: the AD7414/AD7415-0, AD7414/AD7415-1, AD7414-2,
and AD7414-3. The AD7414/AD7415-0 and AD7414/AD7415-1
versions provide a choice of three different SMBus addresses for
each version. All four AD7414 versions give the possibility of eight
different I
2
C addresses while the two AD7415 versions allow up to
six I
2
C addresses to be used.
The AD7414/AD7415’s 2.7 V supply voltage, low supply current,
serial interface, and small package size make them ideal for a
variety of applications, including personal computers, office
equipment, cellular phones, and domestic appliances.
In the AD7414, on-chip registers can be programmed with high
and low temperature limits, and an open-drain overtemperature
indicator output (ALERT) becomes active when a programmed
Rev. E
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.
limit is exceeded. A configuration register allows programming of
the state of the ALERT output (active high or active low). This
output can be used as an interrupt or as an SMBus alert.
PRODUCT HIGHLIGHTS
1. On-chip temperature sensor. The sensor allows an accurate
measurement of the ambient temperature to be made. It is
capable of ±0.5°C temperature accuracy.
2. SMBus/I
2
C-compatible serial interface. The interface offers pin
selectable choice of three addresses per version of the
AD7414/AD7415, eight address options in total for the AD7414,
and six in total for the AD7415.
3. Supply voltage of 2.7 V to 5.5 V.
4. Space-saving 5-lead and 6-lead SOT-23 packages.
5. 10-bit temperature reading to 0.25°C resolution.
6. Overtemperature indicator. This indicator can be software
disabled. It is used as an interrupt of SMBus alert.
7. One-shot and automatic temperature conversion rates.
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.
02463-001
SMBus/I
2
C
INTERFACE
SCL
AD7414/AD7415
TABLE OF CONTENTS
Specifications .....................................................................................3
Absolute Maximum Ratings ............................................................5
ESD Caution ..................................................................................5
Pin Configurations and Function Descriptions............................6
Theory of Operation .........................................................................7
Circuit Information ......................................................................7
Functional Description.................................................................7
Measurement Technique..............................................................7
Temperature Data Format............................................................8
Internal Register Structure...............................................................9
Address Pointer Register ..............................................................9
Configuration Register (Address 0
X
01) .....................................9
Temperature Value Register (Address 0
X
00) ...........................10
AD7414 T
HIGH
Register (Address 0
X
02) ...................................10
AD7414 T
LOW
Register (Address 0
X
03) ....................................10
Serial Interface.................................................................................12
Serial Bus Address.......................................................................12
Write Mode ..................................................................................12
Read Mode ...................................................................................12
SMB
US
ALERT ............................................................................13
Power-On Defaults .....................................................................13
Operating Modes ........................................................................13
Power vs. Throughput ................................................................14
Mounting the AD7414/AD7415 ...............................................14
Supply Decoupling......................................................................14
Temperature Accuracy vs. Supply.............................................15
Typical Temperature Error Graph ............................................15
Outline Dimensions........................................................................16
Ordering Guide ...........................................................................17
REVISION HISTORY
4/05—Rev. D to Rev. E
Updated Format.................................................................. Universal
Changes to Absolute Maximum Ratings........................................6
Changes to Figure 6...........................................................................7
Changes to Ordering Guide...........................................................17
9/04—REV. C to REV. D.
Changes to ABSOLUTE MAXIMUM RATINGS.........................3
Updated ORDERING GUIDE.........................................................4
8/03—REV. B to REV. C.
Change to Temperature Range ......................................... Universal
Updated FEATURES.........................................................................1
Updated SPECIFICATIONS............................................................2
Updated ABSOLUTE MAXIMUM RATINGS .............................3
Updated ORDERING GUIDE.........................................................4
Updated CIRCUIT INFORMATION ............................................5
Updated TEMPERATURE DATA FORMAT................................6
Updated TEMPERATURE VALUE REGISTER ...........................8
Updated Figure 14...........................................................................11
Updated OUTLINE DIMENSIONS .............................................12
11/02—REV.
A to REV. B.
Changes to ABSOLUTE MAXIMUM RATINGS.........................3
10/02—REV. 0 to REV. A.
Changes to SPECIFICATIONS .......................................................2
Changes to PIN FUNCTION DESCRIPTIONS ...........................3
Changes to ABSOLUTE MAXIMUM RATINGS.........................3
ORDERING GUIDE updated .........................................................4
Change to Figure 2 ............................................................................5
Added to TYPICAL TEMPERATURE
ERROR GRAPH section ................................................................11
Added Figure 15 ..............................................................................11
OUTLINE DIMENSIONS updated..............................................12
7/01—Revision 0: Initial Version
Rev. E | Page 2 of 20
AD7414/AD7415
SPECIFICATIONS
T
A
= T
MIN
to T
MAX
, V
DD
= 2.7 V to 5.5 V, unless otherwise noted. Temperature range as follows: A version = −40°C to +125°C.
Table 1.
Parameter
TEMPERATURE SENSOR AND ADC
Accuracy
1
A Version
±0.5
−0.87 to +0.82
2
±1.5
±2.0
±3.0
±2.0
±1.87
±2.0
±3.0
±3.0
10
800
25
2
Unit
°C typ
°C max
°C max
°C max
°C max
°C typ
°C max
°C typ
°C max
°C typ
Bits
ms typ
µs typ
Test Conditions/Comments
V
DD
= 3 V @ +40°C
V
DD
= 3 V @ +40°C
V
DD
= 3 V @ −40°C to +70°C
V
DD
= 3 V @ −40°C to +85°C
V
DD
= 3 V @ −40°C to +125°C
V
DD
= 3 V @ −40°C to +125°C
V
DD
= 5.5 V @ +40°C
V
DD
= 5.5 V @ −40°C to +85°C
V
DD
= 5.5 V @ −40°C to +85°C
V
DD
= 5.5 V @ −40°C to +125°C
Resolution
Update Rate, t
R
Temperature Conversion Time
POWER SUPPLIES
Supply Current
3
Peak Supply Current
4
Supply Current – Nonconverting
Inactive Serial Bus
5
Normal Mode @ 3 V
Normal Mode @ 5 V
Active Serial Bus
6
Normal Mode @ 3 V
Normal Mode @ 5 V
Shutdown Mode
DIGITAL INPUT
Input High Voltage, V
IH
Input Low Voltage, V
IL
Input Current, I
IN7
Input Capacitance, C
IN
DIGITAL OUTPUT (OPEN-DRAIN)
Output High Voltage, V
OH
Output Low Voltage, V
OL
Output High Current, I
OH
Output Capacitance, C
OUT
ALERT Output Saturation Voltage
AC ELECTRICAL CHARACTERISTICS
8, 9
Serial Clock Period, t
1
Data In Setup Time to SCL High, t
2
Data Out Stable after SCL Low, t
3
1.2
900
169
188
180
214
3
mA typ
µA max
µA typ
µA typ
µA typ
µA typ
µA max
Current during conversion
Peak current between conversions
Supply current with serial bus inactive. Part not
converting and D7 of configuration register = 0.
Supply current with serial bus active. Part not
converting and D7 of configuration register = 0.
D7 of configuration register = 1. Typical values
are 0.04 µA at 3 V and 0.5 µA at 5 V.
2.4
0.8
±1
10
2.4
0.4
1
10
0.8
2.5
50
0
V min
V max
µA max
pF max
V min
V max
µA max
pF max
V max
µs min
ns min
ns min
V
IN
= 0 V to V
DD
All digital inputs
I
OL
= 1.6 mA
V
OH
= 5 V
Typ = 3 pF
I
OUT
= 4 mA
See Figure 2
See Figure 2
See Figure 2
Rev. E | Page 3 of 20
AD7414/AD7415
Parameter
SDA Low Setup Time to SCL Low
(Start Condition), t
4
SDA High Hold Time after SCL High
(Stop Condition), t
5
SDA and SCL Fall Time, t
6
Power-Up Time
A Version
50
50
90
4
Unit
ns min
ns min
ns max
µs typ
Test Conditions/Comments
See Figure 2
See Figure 2
See Figure 2
1
Accuracy specifications apply only to voltages listed under Test Conditions. See Temperature Accuracy vs. Supply section for typical accuracy performance over the
full V
DD
supply range.
2
100% production tested at 40°C to these limits.
3
These current values can be used to determine average power consumption at different one-shot conversion rates. Average power consumption at the automatic
conversion rate of 1.25 kHz is 940 µW.
4
This peak supply current is required for 29 µs (the conversion time plus power-up time) out of every 800 µs (the conversion rate).
5
These current values are derived by not issuing a stop condition at the end of a write or read, thus preventing the part from going into a conversion.
6
The current is derived assuming a 400 kHz serial clock being active continuously.
7
On power-up, the initial input current, I
IN
, on the AS pin is typically 50 µA.
8
The SDA and SCL timing is measured with the input filters turned on so as to meet the fast mode I
2
C specification. Switching off the input filters improves the transfer
rate but has a negative effect on the EMC behavior of the part.
9
Guaranteed by design. Not tested in production.
SCL
t
1
t
4
SDA
DATA IN
SDA
DATA OUT
t
2
t
5
t
3
02463-002
t
6
Figure 2. Diagram for Serial Bus Timing
Rev. E | Page 4 of 20
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