AD7818

Features:

` 10-Bit ADC with 9
s Conversion Time
` One (AD7818) and Four (AD7817) Single-Ended Analog
` Input Channels
` The AD7816 Is a Temperature Measurement Only Device
` On-Chip Temperature Sensor
` Resolution of 0.25 2 Error from 40 to +85
55 to +125 Operating Range
` Wide Operating Supply Range 2.7 V to 5.5 V
` Inherent Track-and-Hold Functionality
` On-Chip Reference (2.5 V  1%)
` Overtemperature Indicator
` Automatic Power-Down at the End of a Conversion
` Low Power Operation
- 4
W at a Throughput Rate of 10 SPS
- 40
W at a Throughput Rate of 1 kSPS
- 400
W at a Throughput Rate of 10 kSPS
` Flexible Serial Interface


Application

· Ambient Temperature Monitoring (AD7816)
· Thermostat and Fan Control
· High Speed Microprocessor
· Temperature Measurement and Control
· Data Acquisition Systems with Ambient Temperature
· Monitoring (AD7817 and AD7818)
· Industrial Process Control
· Automotive
· Battery Charging Applications


Pinout




Specifications

VDD to AGND . . . . . . . . . . . . . . . . . . . . . . . . 0.3 V to +7 V
VDD to DGND . . . . . . . . . . . . . . . . . . . . . . . . 0.3 V to +7 V
Analog Input Voltage to AGND
VIN1 to VIN4 . . . . . . . . . . . . . . . . . . .0.3 V to VDD + 0.3 V
Reference Input Voltage to AGND2 . .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
Storage Temperature Range . . . . . . . . . 65°C to +150°C
Junction Temperature . . . . . . . . . . . . . . . . . . . . . . . 150°C
TSSOP, Power Dissipation . . . . . . . . . . . . . . . . . . .450 mW
JA 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
JA 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
JA Thermal Impedance . . . . . . . . . . . . . . . . . . . 157°C/W
Lead Temperature, Soldering
Vapor Phase (60 sec) . . . . . . . . . . . . . . . . . . . . . . .215°C
Infrared (15 sec) . . . . . . . . . . . . . . . . . . . . . . . . . . 220°C
SOIC Package, Power Dissipation . . . . . . . . . . .450 mW
JA Thermal Impedance . . . . . . . . . . . . . . . . . . .206°C/W
Lead Temperature, Soldering
Vapor Phase (60 sec) . . . . . . . . . . . . . . . . . . . . . . .215°C
Infrared (15 sec) . . . . . . . . . . . . . . . . . . . . . . . . . . 220°C


Description

The AD7818 and AD7817 are 10-bit, single- and 4-channel A/D converters with on-chip temperature sensor that can operate from a single 2.7 V to 5.5 V power supply. Each part contains a 9 s successive-approximation converter based around a capacitor DAC, an on-chip temperature sensor with an accuracy of
2°C, an on-chip clock oscillator, inherent track-andhold functionality and an on-chip reference (2.5 V). The AD7816 is a temperature monitoring only device in a SOIC/ MSOP package.

The on-chip temperature sensor of the AD7817 and AD7818 can be accessed via 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 with a resolution of
0.25°C. See Temperature Measurement section of this data sheet.

The AD7816, AD7817, and AD7818 have a flexible serial interface that allows easy interfacing to most microcontrollers. The interface is compatible with the Intel 8051, Motorola SPI® and QSPI™ protocols and National Semiconductors MICROWIRE™ protocol. For more information refer to the Serial Interface section of this data sheet.

The AD7817 is available in a narrow body 0.15" 16-lead small outline IC (SOIC), in a 16-lead, thin shrink small outline package (TSSOP), while the AD7816/AD7818 come in an 8-lead small outline IC (SOIC) and an 8-lead microsmall outline IC (MSOP).