GENERAL 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 µs 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-and hold 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).

FEATURES
  10-Bit ADC with 9 μs 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°C
     ±2°C Error from –40°C to +85°C
     –55°C to +125°C 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 μW at a Throughput Rate of 10 SPS
     40 μW at a Throughput Rate of 1 kSPS
     400 μW at a Throughput Rate of 10 kSPS
  Flexible Serial Interface
 
APPLICATIONS
  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