10-Bit Digital Temperature Sensor
(AD7416) and Four Single-Channel ADCs
AD7416/AD7417/AD7418
FEATURES
10-bit ADC with 15 μs and 30 μs conversion times
Single and 4 single-ended analog input channels
On-chip temperature sensor: −40°C to +125°C
On-chip track-and-hold
Overtemperature indicator
Automatic power-down at the end of a conversion
Wide operating supply range: 2.7 V to 5.5 V
I
2
C-compatible serial interface
Selectable serial bus address allows connection of up to 8
AD7416/AD7417 devices to a single bus
AD7416 is a superior replacement for LM75
A0
7
A1
6
FUNCTIONAL BLOCK DIAGRAMS
BAND GAP
TEMPERATURE
SENSOR
10-BIT
ANALOG-TO-DIGITAL
CONVERTER
TEMPERATURE
VALUE
REGISTER
ADDRESS
POINTER
REGISTER
T
OTI
SETPOINT
REGISTER
T
HYST
SETPOINT
REGISTER
CONFIGURATION
REGISTER
SERIAL BUS
INTERFACE
FAULT
QUEUE
COUNTER
AD7416
SETPOINT
COMPARATOR
8
V
DD
3
OTI
4
GND
1
SDA
2
SCL
01126-001
APPLICATIONS
Data acquisition with ambient temperature monitoring
Industrial process control
Automotive
Battery-charging applications
Personal computers
A2
5
Figure 1. AD7416
REF
IN
5
V
DD
14
T
OTI
SETPOINT
B
REGISTER
TEMP
SENSOR
REF
2.5V
A
IN1 7
A
IN2 8
A
IN3 9
A
IN4 10
V
BALANCE
1
16
6
15
13
A>B
A
4
OTI
GENERAL DESCRIPTION
The AD7417 and AD7418 are 10-bit, 4-channel and single-channel
ADCs with an on-chip temperature sensor that can operate from a
single 2.7 V to 5.5 V power supply. The devices contain a 15 μs
successive approximation converter, a 5-channel multiplexer, a
temperature sensor, a clock oscillator, a track-and-hold, and a
reference (2.5 V). The AD7416 is a temperature-monitoring only
device in an 8-lead package.
The temperature sensor on the parts can be accessed via multip-
lexer Channel 0. When Channel 0 is selected and a conversion
is initiated, the resulting ADC code at the end of the conversion
gives a measurement of the ambient temperature (±1°C @ 25°C).
On-chip registers can be programmed with high and low tempera-
ture limits, and an open-drain overtemperature indicator (OTI)
output is provided, which becomes active when a programmed
limit is exceeded.
A configuration register allows programming of the sense of the
OTI output (active high or active low) and its operating mode
(comparator or interrupt). A programmable fault queue counter
allows the number of out-of-limit measurements that must
occur before triggering the OTI output to be set to prevent
spurious triggering of the OTI output in noisy environments.
CHARGE
DISTRIBUTION
DAC
DATA OUT
MUX
SAMPLING
CAPACITOR
I
2
C
CLOCK CONTROL
LOGIC
INTERFACE
3
SCL
SDA
2
AD7417
12
11
01126-002
NC
NC
GND
CONVST
A0
A1
A2
NC = NO CONNECT
Figure 2. AD7417
V
DD
7
REF
IN
6
T
OTI
SETPOINT B
REGISTER
TEMP
SENSOR
REF
2.5V
A
IN 5
MUX
SAMPLING
CAPACITOR
CHARGE
DISTRIBUTION
DAC
A>B
A
DATA OUT
3
OTI
I
2
C
CLOCK CONTROL
LOGIC
INTERFACE
2
SCL
SDA
1
AD7418
4
8
01126-003
V
BALANCE
GND
CONVST
Figure 3. AD7418
Rev. I
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 ©1998–2010 Analog Devices, Inc. All rights reserved.
AD7416/AD7417/AD7418
TABLE OF CONTENTS
Features .............................................................................................. 1
Applications....................................................................................... 1
General Description ......................................................................... 1
Functional Block Diagrams............................................................. 1
Revision History ............................................................................... 2
Product Highlights ........................................................................... 3
Specifications..................................................................................... 4
AD7417/AD7418 Specifications................................................. 4
AD7416 Specifications................................................................. 6
Absolute Maximum Ratings............................................................ 7
ESD Caution.................................................................................. 7
Pin Configurations and Function Descriptions ........................... 8
Terminology .................................................................................... 10
Theory of Operation ...................................................................... 11
Circuit Information.................................................................... 11
Converter Details........................................................................ 11
Typical Connection Diagram ................................................... 11
Analog Inputs.............................................................................. 11
On-Chip Reference .................................................................... 11
Temperature Measurement ....................................................... 12
Internal Register Structure........................................................ 12
Serial Bus Interface..................................................................... 14
OTI Output ................................................................................. 17
Fault Queue ................................................................................. 17
Power-On Defaults..................................................................... 17
Operating Modes........................................................................ 17
CONVST Start Mode................................................................. 18
Applications Information .............................................................. 19
Supply Decoupling ..................................................................... 19
Power-On Reset.......................................................................... 19
Mounting the AD7416/AD7417/AD7418 .............................. 19
Fan Controller............................................................................. 19
Thermostat .................................................................................. 19
System with Multiple AD7416 Devices................................... 20
Outline Dimensions ....................................................................... 21
Ordering Guide .......................................................................... 23
REVISION HISTORY
11/10—Rev. H to Rev. I
Changes to Figure 19...................................................................... 16
2/09—Rev. G to Rev. H
Updated Format..................................................................Universal
Changes to Data Sheet Title, Figure 2 and Figure 3..................... 1
Moved Product Highlights Section................................................ 3
Changes to Table 1............................................................................ 4
Changes to Endnote 1, Table 2........................................................ 6
Added Figure 5 Caption................................................................... 7
Changes to Table 4............................................................................ 8
Changes to Table 5 and Table 6....................................................... 9
Changes to On-Chip Reference Section...................................... 11
Changes to Figure 13...................................................................... 12
Changes to Table 8 and Table 10................................................... 13
Changes to Figure 15, Figure 16, and Figure 17 ......................... 15
Changes to Reading Data From the AD7416/AD7417/AD7418
Section, Figure 18, and Figure 19 ................................................. 16
Change to Mode 1 .......................................................................... 17
Changes to Figure 22 Caption and CONVST Pin Mode
Section.............................................................................................. 18
Moved Figure 21 and Figure 22 .................................................... 18
Changes to Power-On Reset Section............................................ 19
Updated Outline Dimensions ....................................................... 21
Changes to Ordering Guide .......................................................... 23
8/04—Data Sheet Changed from Rev. F to Rev. G
Changes to Figure 12...................................................................... 12
Changes to Reading Data from the AD7416/AD7417/AD7418
Section.............................................................................................. 13
Changes to Power-On-Reset section ........................................... 14
7/03—Data Sheet Changed from Rev. E to Rev. F
Updated Features...............................................................................1
Updated Specifications .....................................................................3
Updated Absolute Maximum Ratings ............................................6
Updated Ordering Guide .................................................................6
Updated Product Highlights............................................................7
Updated Circuit Information...........................................................7
Updated Temperature Measurement section ................................9
10/02—Data Sheet Changed from Rev. D to Rev. E
Edits to Specifications Headings .....................................................2
Added Temperature Measurement section....................................8
Edits to Serial Bus Address section .............................................. 10
Edits to Figure 11............................................................................ 12
Edits to CONVST Pin Mode section ........................................... 14
Edits to Power-On-Reset section ................................................. 14
Addition of Figures 16 and 17 ...................................................... 15
Updated Outlines ........................................................................... 16
Rev. I | Page 2 of 24
AD7416/AD7417/AD7418
An I
2
C® compatible serial interface allows the AD7416/AD7417/
AD7418 registers to be written to and read back. The three
LSBs of the AD7416/AD7417 serial bus address can be selected,
which allows up to eight AD7416/AD7417 devices to be connected
to a single bus.
The AD7417 is available in a narrow body, 0.15 inch, 16-lead,
small outline package (SOIC) and in a 16-lead, thin shrink,
small outline package (TSSOP). The AD7416 and AD7418 are
available in 8-lead SOIC and MSOP packages.
2.
made. The measurable temperature range is −40°C to
+125°C. An overtemperature indicator is implemented by
carrying out a digital comparison of the ADC code for
Channel 0 (temperature sensor) with the contents of the
on-chip T
OTI
setpoint register.
The AD7417 offers a space-saving, 10-bit analog-to-digital
solution with four external voltage input channels, an on-
chip temperature sensor, an on-chip reference, and a clock
oscillator.
The automatic power-down feature enables the AD7416/
AD7417/AD7418 to achieve superior power performance.
At slower throughput rates, the part can be programmed to
operate in a low power shutdown mode, allowing further
savings in power consumption.
PRODUCT HIGHLIGHTS
1.
The AD7416/AD7417/AD7418 have an on-chip temperature
sensor that allows an accurate measurement of the ambient
temperature (±1°C @ 25°C, ±2°C overtemperature) to be
3.
Rev. I | Page 3 of 24
AD7416/AD7417/AD7418
SPECIFICATIONS
AD7417/AD7418 SPECIFICATIONS
V
DD
= 2.7 V to 5.5 V, GND = 0 V, REF
IN
= 2.5 V, unless otherwise noted.
Table 1.
Parameter
DC ACCURACY
Resolution
Minimum Resolution for Which No
Missing Codes Are Guaranteed
Relative Accuracy
2
Differential Nonlinearity
2
Gain Error
2
Gain Error Match
2
Offset Error
2
Offset Error Match
2
ANALOG INPUTS
Input Voltage Range
Input Leakage Current
3
Input Capacitance
TEMPERATURE SENSOR
1
Measurement Error
Ambient Temperature 25°C
T
MIN
to T
MAX
Temperature Resolution
CONVERSION RATE
Track-and-Hold Acquisition Time
4
Conversion Time
Temperature Sensor
Channel 1 to Channel 4
REFERENCE INPUT
5,6
REF
IN
Input Voltage Range
Input Impedance
Input Capacitance
ON-CHIP REFERENCE
Reference Error
6
Temperature Coefficient
6
DIGITAL INPUTS
Input High Voltage, V
IH
Input Low Voltage, V
IL
Input Leakage Current
DIGITAL OUTPUTS
Output Low Voltage, V
OL
Output High Current
A Version
10
10
±1
±1
±3
±10
±0.6
±4
±0.7
VREF
0
±1
10
B Version
1
10
10
±1
±1
±3
±10
±0.6
±4
±0.7
VREF
0
±1
10
Unit
Bits
Bits
LSB max
LSB max
LSB max
LSB max
LSB max
LSB max
LSB max
V max
V min
μA max
pF max
This specification is typical for V
DD
of 3.6 V to 5.5 V
This specification is typical for V
DD
of 3.6 V to 5.5 V
External reference
Internal reference
AD7417 only
AD7417 only
Test Conditions/Comments
Any channel
±2
±3
1/4
400
30
15
2.625
2.375
40
10
±25
80
V
DD
× 0.7
V
DD
× 0.3
1
0.4
1
±1
±2
1/4
400
30
15
2.625
2.375
40
10
±25
80
V
DD
× 0.7
V
DD
× 0.3
1
0.4
1
°C max
°C max
°C/LSB
ns max
μs max
μs max
V max
V min
kΩ min
pF max
mV max
ppm/°C typ
V min
V max
μA max
V max
μA max
I
OL
= 3 mA
V
OH
= 5 V
Source impedance < 10 Ω
Typically 27 μs
Typically 10 μs
2.5 V + 5%
2.5 V − 5%
Nominal 2.5 V
Rev. I | Page 4 of 24
AD7416/AD7417/AD7418
Parameter
POWER REQUIREMENTS
V
DD
I
DD
Normal Operation
Power-Down
Auto Power-Down Mode
10 SPS Throughput Rate
1 kSPS Throughput Rate
10 kSPS Throughput Rate
Power-Down
1
A Version
5.5
2.7
600
1.5
6
60
600
3
B Version
1
5.5
2.7
600
1.5
6
60
600
3
Unit
V max
V min
μA max
μA max
μW typ
μW typ
μW typ
μW max
Test Conditions/Comments
For specified performance
Logic inputs = 0 V or V
DD
0.7 μA typically
V
DD
= 3 V; see the Operating Modes section
Typically 0.15 μW
B Version applies to AD7417 only with temperature range of −40°C to +85°C. A Version temperature range is −40°C to +125°C. For V
DD
= 2.7 V, T
A
= 85°C maximum and
temperature sensor measurement error = ±3°C maximum.
2
See the Terminology section.
3
Refers to the input current when the part is not converting. Primarily due to reverse leakage current in the ESD protection diodes.
4
Sample tested during initial release and after any redesign or process change that may affect this parameter.
5
On-chip reference shuts down when an external reference is applied.
6
The accuracy of the temperature sensor is affected by reference tolerance.
Rev. I | Page 5 of 24
