Analog Devices AD7418ARM, AD7418AR, AD7417BR, AD7417AR, AD7416ARM Datasheet

10-Bit Digital Temperature Sensor (AD7416) and

a

Four/Single-Channel ADCs (AD7417/AD7418)

FEATURES
10-Bit ADC with 15 ␮s and 30 ␮s Conversion Times
Single and Four Single-Ended Analog Input Channels
On-Chip Temperature Sensor: –55ⴗC to +125ⴗC
On-Chip Track/Hold
Over-Temperature Indicator
Automatic Power Down at the End of a Conversion
Wide Operating Supply Range: 2.7 V to 5.5 V

2C®

-Compatible Serial Interface

I
Selectable Serial Bus Address Allows Connection of Up

to Eight AD7416/AD7417s 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- and single-channel
A/D converters 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/
hold, and a reference (2.5 V). The AD7416 is a temperature­monitoring-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 Over-Temperature 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.

(continued on page 7)

I2C is a registered trademark of Philips Corporation.

A0

A1

A2

V

IN1

V

IN2

V

IN3

V

IN4

NC = NO CONNECT

V

IN1

AD7416/AD7417/AD7418

FUNCTIONAL BLOCK DIAGRAMS

BANDGAP

TEMPERATURE

SENSOR

ADDRESS

POINTER

REGISTER

TEMP

SENSOR

MUX

NC NC GND

V

DD

TEMP

SENSOR

MUX

AGND

REF

REF

2.5V

SAMPLING

CAPACITOR

REF

2.5V

SAMPLING

CAPACITOR

ANALOG-DIGITAL

CONVERTER

TEMPERATURE

VALUE

REGISTER

T

OTI

REGISTER

T

HYST

REGISTER

CONFIGURATION

REGISTER

SERIAL BUS

INTERFACE

IN

V

BALANCE

REF

IN

V

BALANCE

10-BIT

SETPOINT

SETPOINT

V

DD

OVER-TEMP REG

CHARGE

DISTRIBUTION

DAC

CONTROL

CLOCK

CONVST

OVER-TEMP REG

CLOCK

CONVST

LOGIC

+

CHARGE

DISTRIBUTION

DAC

CONTROL

LOGIC

+

AD7416

SETPOINT

COMPARATOR

FAULT

QUEUE

COUNTER

A > B

B

A

DATA OUT

I2C

INTERFACE

AD7417

A > B

B

A

DATA OUT

I2C

INTERFACE

AD7418

A2A1A0

+V

OTI

GND

SDA

SCL

OTI

SCL

SDA

OTI

SCL

SDA

S

REV. D

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. No license is granted by implication or otherwise
under any patent or patent rights of Analog Devices.

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: [phone] www.analog.com
Fax: [phone] © Analog Devices, Inc., 2002

AD7416/AD7417/AD7418

AD7417/AD7418–SPECIFICATIONS

Parameter A Version B Version

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

1

Unit Test Conditions/Comments

DC ACCURACY Any Channel

Resolution 10 10 Bits
Minimum Resolution for Which No

Missing Codes are Guaranteed 10 10 Bits

Relative Accuracy

Differential Nonlinearity

Gain Error

Gain Error Match
Offset Error

2

2

2

2

2

± 1 ± 1 LSB max This Spec Is Typical for VDD of

3.6 V to 5.5 V

± 1 ± 1 LSB max This Spec Is Typical for VDD of

3.6 V to 5.5 V

± 3 ± 3 LSB max External Reference
± 10 ± 10 LSB max Internal Reference
± 0.6 ± 0.6 LSB max AD7417 Only
± 4 ± 4 LSB max

Offset Error Match ± 0.7 ± 0.7 LSB max AD7417 Only

ANALOG INPUTS

Input Voltage Range V

Input Leakage Current

3

REF

V

REF

00V min
± 1 ± 1 µA max

V max

Input Capacitance 10 10 pF max

TEMPERATURE SENSOR

1

Measurement Error

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

MIN

to T

MAX

± 3 ± 2 °C max

Temperature Resolution 1/4 1/4 °C/LSB

CONVERSION RATE

Track/Hold Acquisition Time

4

400 400 ns max Source Impedance < 10 Ω

Conversion Time

Temperature Sensor 30 30 µs max Typically 27 µs

Channels 1 to 4 15 15 µs max Typically 10 µs

REFERENCE INPUT

REFIN Input Voltage Range

5, 6

6

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 Error
Temperature Coefficient

6

6

± 25 ± 25 mV max
80 80 ppm/°C typ

DIGITAL INPUTS

Input High Voltage, V
Input Low Voltage, V

IL

IH

+VS × 0.7 +VS × 0.7 V min
+VS × 0.3 +VS × 0.3 V max

Input Leakage Current 1 1 µA max

DIGITAL OUTPUTS

Output Low Voltage, V

OL

0.4 0.4 V max IOL = 3 mA
Output High Current 1 1 µA max VOH = 5 V

POWER REQUIREMENTS

V

DD

5.5 5.5 V max For Specified Performance

2.7 2.7 V min
I

DD

Logic Inputs = 0 V or V
Normal Operation 600 600 µA max
Power Down 1 1 µA max 50 nA Typically

Auto Power-Down Mode V

= 3 V. See Operating Modes

DD

10 sps Throughput Rate 6 6 µW typ
1 ksps Throughput Rate 60 60 µW typ
10 ksps Throughput Rate 600 600 µW typ

Power Down 3 3 µW max Typically 0.15 µW

DD

–2–

REV. D

AD7416/AD7417/AD7418

NOTES

1

B version applies to AD7417 only with temperature range of –40°C to +85°C. A version temperature range is –55°C to +125°C. For VDD = 2.7 V, TA = 85°C max
and temperature sensor measurement error = ± 3°C.

2

See Terminology.

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 external reference is applied.

6

The accuracy of the temperature sensor is affected by reference tolerance. The relationship between the two is explained in the section titled Temperature Sensor.

Specifications subject to change without notice.

AD7416–SPECIFICATIONS

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

Parameter Min Typ Max Unit Test Conditions/Comments

TEMPERATURE SENSOR AND ADC

Accuracy ± 2.0 °CT

± 3.0 °CT

= –25°C to +100°C (VDD = 3 V min)

A

= –55°C to +125°C (VDD = 3 V min)

A

Resolution 10 Bits
Temperature Conversion Time 40 µs
Update Rate, t
OTI Delay 1 × t

R

R

Supply Current 1.0 mA I

400 µs

6 × t

R

350 600 µAI

ms Depends on Fault Queue Setting

2

C Active

2

C Inactive

0.2 1.5 µA Shutdown Mode

Default Temperature 80 °C

T

OTI

T

Default Temperature 75 °C

HYST

DIGITAL INPUTS

Input High Voltage, V
Input Low Voltage, V

IL

Input High Current, I
Input Low Current, I
Input Capacitance, C

IL

IN

IH

IH

+VS × 0.7 +VS + 0.5 V
–0.3 +VS × 0.3 V

0.005 1.0 µAV
–0.005 –1.0 µAV
20 pF All Digital Inputs

= 5 V

IN

= 0 V

IN

DIGITAL OUTPUTS

Output Low Voltage, V

OL

Output High Current 1 µAV
Output Fall Time, t
OS Output Low Voltage, V

AC ELECTRICAL CHARACTERISTICS

Serial Clock Period, t
Data In Setup Time to SCL High, t
Data Out Stable after SCL Low, t

f

OL

2

1

2

3

2.5 µs See Figure 1
50 ns See Figure 1
0 ns See Figure 1

0.4 V IOL = 3 mA
= 5 V

OH

250 ns CL = 400 pF, IO = 3 mA

0.8 V I

OUT

= 4 mA

AD7416/AD7417/AD7418

SDA Low Setup Time to SCL Low

(Start Condition), t

4

50 ns See Figure 1

SDA High Hold Time after SCL High

(Stop Condition), t

SDA and SCL Fall Time, t

NOTES

1

For VDD = 2.7 V to 3 V, TA max = 85°C and accuracy = ± 3°C.

2

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

Specifications subject to change without notice.

5

6

50 ns See Figure 1

300 ns See Figure 1

1

1

t

1

SCL

SDA

DATA IN

SDA

DATA OUT

t

4

t

2

Figure 1. Diagram for Serial Bus Timing

REV. D –3–

t

5

t

3

t

6

AD7416/AD7417/AD7418

AD7417 PIN FUNCTION DESCRIPTION

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 is a logic output. The Over Temperature Indicator (OTI) is set if the result of a conversion on

Channel 0 (temperature sensor) is greater than an 8-bit word in the Over Temperature Register (OTR).
The signal is reset at the end of a serial read operation. Open-drain output.

5 REF

IN

6 GND Ground Reference for Track/Hold, Comparator and Capacitor DAC, and Digital Circuitry.
7–10 A

IN1

to A

11 A2 Digital Input. The highest programmable bit of the Serial Bus Address.
12 A1 Digital Input. The middle programmable bit of the Serial Bus Address.
13 A0 Digital Input. The lowest programmable bit of the Serial Bus Address.
14 V

DD

15 CONVST Logic Input Signal. Convert Start Signal. The rising edge of this signal fully powers up the part. The

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

IN

the AD7417, the internal reference will shut down.

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

IN4

ended with respect to GND. The input channels can convert voltage signals in the range 0 V to V
A channel is selected by writing to the configuration register of the AD7417. (See Control Byte section.)

Positive Supply Voltage, 2.7 V to 5.5 V.

power-up time for the part is 4 µs. If the CONVST pulse is greater than 4 µs, the falling edge of
CONVST places the track/hold mode into hold mode and initiates a conversion. If the pulse is less
than 4 µs, an internal timer ensures that the track/hold does not go into hold and conversion is not
initiated until the power-up time has elapsed. The track/hold goes into track mode again at the end of
conversion. (See Operating Mode section.)

REF

.

AD7417 PIN CONFIGURATION

SOIC/TSSOP

1

NC

2

SDA

3

SCL

4

OTI

5

REF

IN

6

GND

7

A

IN1

8

A

IN2

NC = NO CONNECT

AD7417

TOP VIEW

(Not to Scale)

16

15

14

13

12

11

10

9

NC

CONVST

V

DD

A0

A1

A2

A

IN4

A

IN3

–4–

REV. D

AD7416/AD7417/AD7418

AD7416 PIN FUNCTION DESCRIPTION

Pin No. Mnemonic Description

1 SDA Digital I/O. Serial Bus Bidirectional Data. Push-pull output.
2 SCL Digital Input. Serial Bus Clock.

3 OTI This is a logic output. The Over-Temperature Indicator (OTI) is set if the result of a conversion on

Channel 0 (Temperature Sensor) is greater that an 8-bit word in the Over-Temperature Register

(OTR). The signal is reset at the end of a serial read operation. Open-drain output.
4 GND Ground reference for track/hold, comparator and capacitor DAC, and digital circuitry.
5 A2 Digital Input. The highest programmable bit of the Serial Bus Address.
6 A1 Digital Input. The middle programmable bit of the Serial Bus Address.
7 A0 Digital Input. The lowest programmable bit of the Serial Bus Address.
8VDDPositive Supply Voltage, 2.7 V to 5.5 V.

AD7418 PIN FUNCTION DESCRIPTION

Pin No. Mnemonic Description

1 SDA Digital I/O. Serial Bus Bidirectional Data. Push-pull output.
2 SCL Digital Input. Serial Bus Clock.

3 OTI This is a logic output. The Over-Temperature Indicator (OTI) is set if the result of a conversion on

Channel 0 (Temperature Sensor) is greater that an 8-bit word in the Over-Temperature Register

(OTR). The signal is reset at the end of a serial read operation. Open-drain output.
4 GND Ground reference for track/hold, comparator and capacitor DAC, and digital circuitry.
5A

6 REF

7V

IN

IN

DD

8 CONVST Logic Input Signal. Convert Start Signal. The rising edge of this signal fully powers up the part.

Analog Input Channel. The input channel is single-ended with respect to GND. The input channel

can convert voltage signals in the range 0 V to V

. The analog input channel is selected by writing

REF

to the configuration register of the AD7418 and choosing Channel 4. (See Control Byte section.)

Reference Input. An external 2.5 V reference can be connected to the AD7418 at this pin. To enable

the on-chip reference the REF

pin should be tied to GND. If an external reference is connected to

IN

the AD7418, the internal reference will shut down.

Positive Supply Voltage, 2.7 V to 5.5 V.

The power-up time for the part is 4 µs. If the CONVST pulse is greater than 4 µs, the falling edge

of CONVST places the track/hold mode into hold mode and initiates a conversion. If the pulse is

less than 4 µs, an internal timer ensures that the track/hold does not go into hold and conversion is

not initiated until the power-up time has elapsed. The track/hold goes into track mode again at the

end of conversion. (See Operating Mode section.)

REV. D

AD7416 PIN CONFIGURATION

SOIC/␮SOIC

SDA

SCL

OTI

GND

1

2

AD7416

TOP VIEW

3

(Not to Scale)

4

8

V

DD

7

A0

6

A1

5

A2

–5–

AD7418 PIN CONFIGURATION

SOIC/␮SOIC

SDA

SCL

OTI

GND

1

2

AD7418

TOP VIEW

3

(Not to Scale)

4

8

CONVST

7

V

6

REF

5

A

DD

IN

IN