ANALOG DEVICES AD7417 Service Manual

10-Bit Digital Temperature Sensor

V

V

(AD7416) and Four Single-Channel ADCs

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

2

I

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

APPLICATIONS

Data acquisition with ambient temperature monitoring
Industrial process control
Automotive
Battery-charging applications
Personal computers

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 multip­lexer 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 tempera­ture 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.

AD7416/AD7417/AD7418

FUNCTIONAL BLOCK DIAGRAMS

BAND GAP

TEMPERATURE

SENSOR

ADDRESS

POINTER

REGISTER

7

A0

6

A1

A2

5

TEMP

SENSOR

7

A

IN1

8

A

IN2

A

IN3

A

IN4

NC = NO CONNECT

A

MUX

9

10

1

16NC6

NC

DD

7

TEMP

SENSOR

5

MUX

IN

ANALOG-TO-DIGITAL

CONVERTER

TEMPERATURE

T

OTI

T

HYST

CONFIGURATION

Figure 1. AD7416

REF

IN

5

REF

2.5V

SAMPLING

CAPACITOR

V

BALANCE

GND

Figure 2. AD7417

REF

IN

6

REF

2.5V

SAMPLING

CAPACITOR

V

BALANCE

4

GND

Figure 3. AD7418

10-BIT

VAL UE

REGISTER

SETPOINT

REGISTER

SETPOINT

REGISTER

REGISTER

SERIAL BUS

INTERFACE

T

SETPOINT

OTI

REGIS TER

CHARGE

DISTRIBUTI ON

DAC

CLOCK

15

CONVST

T

SETPOINT

OTI

REGIS TER

CHARGE

DISTRIBUTI ON

DAC

CONTROL

CLOCK

8

CONVST

DD

14

CONTROL

LOGIC

LOGIC

AD7416

SETPOINT

COMPARATOR

FAULT

QUEUE

COUNTER

A > B

B

A

DATA OUT

2

I

C

INTERFACE

AD7417

13

12 11

A0

A1 A2

A > B

B

A

DATA OUT

2

I

C

INTERFACE

AD7418

8

V

DD

3

OTI

4

GND

SDA

1

2

SCL

01126-001

4

OTI

3

SCL

SDA

2

01126-002

3

OTI

2

SCL

SDA

1

01126-003

Rev. I

Information furnished by Analog Devices is believed to be accurate and reliable. However, no
responsibility is assumed by Anal og Devices for its use, nor for any infringements of patents or ot her
rights of third parties that may result from its use. Specifications subject to change without notice. No
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Tel: [phone] www.analog.com
Fax: [phone] ©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

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

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

CONVST

Pin Mode

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

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

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

Edits to Power-On-Reset section ................................................. 14

Addition of Figures 16 and 17 ...................................................... 15

Updated Outlines ........................................................................... 16

Start Mode................................................................. 18

CONVST

Pin Mode section ........................................... 14

Rev. I | Page 2 of 24

AD7416/AD7417/AD7418

An I2C® 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.

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

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

2. The AD7417 offers a space-saving, 10-bit analog-to-digital

solution with four external voltage input channels, an on­chip temperature sensor, an on-chip reference, and a clock
oscillator.

3. 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.

setpoint register.

OTI

Rev. I | Page 3 of 24

AD7416/AD7417/AD7418

SPECIFICATIONS

AD7417/AD7418 SPECIFICATIONS

VDD = 2.7 V to 5.5 V, GND = 0 V, REFIN = 2.5 V, unless otherwise noted.

Table 1.

Parameter A Version B Version1 Unit Test Conditions/Comments

DC ACCURACY Any channel

Resolution 10 10 Bits
Minimum Resolution for Which No

Missing Codes Are Guaranteed
Relative Accuracy2 ±1 ±1 LSB max This specification is typical for VDD of 3.6 V to 5.5 V
Differential Nonlinearity2 ±1 ±1 LSB max This specification is typical for VDD of 3.6 V to 5.5 V
Gain Error2 ±3 ±3 LSB max External reference
±10 ±10 LSB max Internal reference
Gain Error Match2 ±0.6 ±0.6 LSB max AD7417 only
Offset Error2 ±4 ±4 LSB max
Offset Error Match2 ±0.7 ±0.7 LSB max AD7417 only

ANALOG INPUTS

Input Voltage Range VREF VREF V max
0 0 V min
Input Leakage Current3 ±1 ±1 A max
Input Capacitance 10 10 pF max

TEMPERATURE SENSOR1

Measurement Error

Ambient Temperature 25°C ±2 ±1 °C max
T

to T

MIN

Temperature Resolution 1/4 1/4 °C/LSB

CONVERSION RATE

Track-and-Hold Acquisition Time4 400 400 ns max Source impedance < 10 Ω
Conversion Time

Temperature Sensor 30 30 s max Typically 27 s

Channel 1 to Channel 4 15 15 s max Typically 10 s

REFERENCE INPUT

REFIN Input Voltage Range 2.625 2.625 V max 2.5 V + 5%

2.375 2.375 V min 2.5 V − 5%
Input Impedance 40 40 kΩ min
Input Capacitance 10 10 pF max

ON-CHIP REFERENCE Nominal 2.5 V

Reference Error6 ±25 ±25 mV max
Temperature Coefficient6 80 80 ppm/°C typ

DIGITAL INPUTS

Input High Voltage, VIH VDD × 0.7 VDD × 0.7 V min
Input Low Voltage, VIL VDD × 0.3 VDD × 0.3 V max
Input Leakage Current 1 1 A max

DIGITAL OUTPUTS

Output Low Voltage, VOL 0.4 0.4 V max IOL = 3 mA
Output High Current 1 1 A max VOH = 5 V

±3 ±2 °C max

MAX

5, 6

10 10 Bits

Rev. I | Page 4 of 24

AD7416/AD7417/AD7418

Parameter A Version B Version1 Unit Test Conditions/Comments

POWER REQUIREMENTS

VDD 5.5 5.5 V max For specified performance

2.7 2.7 V min
IDD Logic inputs = 0 V or VDD

Normal Operation 600 600 A max
Power-Down 1.5 1.5 A max 0.7 µA typically

Auto Power-Down Mode VDD = 3 V; see the Operating Modes section

10 SPS Throughput Rate 6 6 W typ
1 kSPS Throughput Rate 60 60 W typ
10 kSPS Throughput Rate 600 600 W typ

Power-Down 3 3 W max Typically 0.15 W

1

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 VDD = 2.7 V, TA = 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

AD7416/AD7417/AD7418

AD7416 SPECIFICATIONS

VDD = 2.7 V to 5.5 V, GND = 0 V, REFIN = 2.5 V, unless otherwise noted.

Table 2.

Parameter Min Typ Max Unit Test Conditions/Comments

TEMPERATURE SENSOR AND ADC

Accuracy ±2.0 °C TA = −25°C to + 100°C
(V
±3.0 °C TA = −40°C to + 125°C
(V
Resolution 10 Bits
Temperature Conversion Time 40 s
Update Rate, tR 400 s
OTI Delay 1 × tR 6 × tR ms Depends on fault queue setting
Supply Current 1.0 mA I2C active
350 600 A I2C inactive

0.2 1.5 A Shutdown mode
T

Default Temperature 80 °C

OTI

T

Default Temperature 75 °C

HYST

DIGITAL INPUTS

Input High Voltage, VIH VDD × 0.7 VDD + 0.5 V
Input Low Voltage, VIL −0.3 VDD × 0.3 V
Input High Current, IIH +0.005 +1.0 A VIN = 5 V
Input Low Current, IIL −0.005 −1.0 A VIN = 0 V
Input Capacitance, CIN 20 pF All digital inputs

DIGITAL OUTPUTS

Output Low Voltage, VOL 0.4 V IOL = 3 mA
Output High Current 1 A VOH = 5 V
Output Fall Time, tf 250 ns CL = 400 pF, IO = 3 mA
OS Output Low Voltage, VOL 0.8 V I

AC ELECTRICAL CHARACTERISTICS2 AD7416/AD7417/AD7418

Serial Clock Period, t1 2.5 s See Figure 4
Data In Setup Time to SCL High, t2 50 ns See Figure 4
Data Out Stable after SCL Low, t3 0 ns See Figure 4
SDA Low Setup Time to SCL Low

(Start Condition), t4 50 ns See Figure 4

SDA High Hold Time after SCL High

(Stop Condition), t5 50 ns See Figure 4

SDA and SCL Fall Time, t6 300 ns See Figure 4

1

For VDD = 2.7 V to 3 V, TA maximum = 85°C and temperature sensor measurement error = ±3°C maximum.

2

Sample tested during initial release and after any redesign or process change that may affect this parameter.

t

1

SCL

= 3 V minimum)1

DD

= 3 V minimum)1

DD

= 4 mA

OUT

SDA

DATA IN

SDA

DATA OUT

t

4

t

2

t

3

t

5

t

6

01126-004

Figure 4. Diagram for Serial Bus Timing

Rev. I | Page 6 of 24

AD7416/AD7417/AD7418

V

ABSOLUTE MAXIMUM RATINGS

TA = 25°C, unless otherwise noted.

Table 3.

Parameter Rating

VDD to AGND −0.3 V to +7 V
VDD to DGND −0.3 V to +7 V
Analog Input Voltage to AGND

A

to A

IN1

−0.3 V to VDD + 0.3 V

IN4

Reference Input Voltage to AGND1 −0.3 V to VDD + 0.3 V
Digital Input Voltage to DGND −0.3 V to VDD + 0.3 V
Digital Output Voltage to DGND −0.3 V to VDD + 0.3 V
Operating Temperature Range

A Version −40°C to +125°C
B Version −40°C to +85°C

Storage Temperature Range −65°C to +150°C
Junction Temperature 150°C
TSSOP, Power Dissipation 450 mW

θJA Thermal Impedance 120°C/W
Lead Temperature, Soldering 260°C

Vapor Phase (60 sec) 215°C
Infrared (15 sec) 220°C

16-Lead SOIC Package, Power Dissipation 450 mW

θJA Thermal Impedance 100°C/W
Lead Temperature, Soldering

Vapor Phase (60 sec) 215°C
Infrared (15 sec) 220°C

8-Lead SOIC Package, Power Dissipation 450 mW

θJA Thermal Impedance 157°C/W
Lead Temperature, Soldering

Vapor Phase (60 sec) 215°C
Infrared (15 sec) 220°C

MSOP Package, Power Dissipation 450 mW

θJA Thermal Impedance 206°C/W
Lead Temperature, Soldering

Vapor Phase (60 sec) 215°C
Infrared (15 sec) 220°C

1

If the reference input voltage is likely to exceed VDD by more than 0.3 V (for

example, during power-up) and the reference is capable of supplying 30 mA
or more, it is recommended to use a clamping diode between the REFIN pin
and the V

pin. Figure 5 shows how the diode should be connected.

DD

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.

REF

IN

AD7417

Figure 5. Diode Connection

BAT81

DD

01126-025

ESD CAUTION

Rev. I | Page 7 of 24

AD7416/AD7417/AD7418

PIN CONFIGURATIONS AND FUNCTION DESCRIPTIONS

NC

1

SDA

2

SCL

3

AD7417

4

OTI

TOP VIEW

5

IN

GND

6

A

7

IN1

8

A

IN2

NC = NO CONNECT

(Not to Scale)

REF

Figure 6. AD7417 Pin Configuration (SOIC/TSSOP)

Table 4. AD7417 Pin Function Descriptions

Pin No. Mnemonic Description

1, 16 NC No Connection. Do not connect anything to this pin.
2 SDA Digital I/O. Serial bus bidirectional data. Push-pull output.
3 SCL Digital Input. Serial bus clock.
4 OTI

This pin is a logic output. The overtemperature indicator (OTI) is set if the result of a conversion on Channel 0
(temperature sensor) is greater than an 8-bit word in the T
serial read operation. Open-drain output.

5 REFIN

Reference Input. An external 2.5 V reference can be connected to the AD7417 at this pin. To enable the on-chip
reference, the REF

pin should be tied to GND. If an external reference is connected to the AD7417, the internal

IN

reference shuts down.
6 GND Ground reference for track-and-hold, comparator and capacitor DAC, and digital circuitry.
7 to 10 A

IN1

to A

Analog Input Channels. The AD7417 has four analog input channels. The input channels are single-ended with

IN4

respect to GND. The input channels can convert voltage signals in the range of 0 V to VREF. A channel is selected by

writing to the configuration register of the AD7417.
11 A2 Digital Input. This is the highest programmable bit of the serial bus address.
12 A1 Digital Input. This is the middle programmable bit of the serial bus address.
13 A0 Digital Input. This is the lowest programmable bit of the serial bus address.
14 VDD Positive Supply Voltage, 2.7 V to 5.5 V.
15

CONVST

Logic Input Signal. Convert start signal. The rising edge of this signal fully powers up the part. The power-up time

for the part is 4 s. If the CONVST pulse is greater than 4 s, the falling edge of CONVST places the track-and-hold

mode into hold mode and initiates a conversion. If the pulse is less than 4 s, an internal timer ensures that the

track-and-hold does not go into hold, and conversion is not initiated until the power-up time has elapsed. The

track-and-hold goes into track mode again at the end of conversion (see the section). Operating Modes

16

15

14

13

12

11

10

9

NC

CONVST

V

DD

A0

A1

A2

A

IN4

A

IN3

01126-005

setpoint register. The signal is reset at the end of a

OTI

Rev. I | Page 8 of 24