4-Channel/Single-Channel, 9 s, 10-Bit ADCs with On-Chip Temperature Sensor Data Sheet AD7817/AD7818 FEATURES FUNCTIONAL BLOCK DIAGRAMS REF V IN DD 10-bit ADC with 9 s conversion time 1 AD7818 and 4 AD7817 single-ended analog input channels AD7817 OVERTEMP B A > B OTI On-chip temperature sensor REG TEMP SENSOR A Resolution of 0.25C CHARGE REF DATA REDISTRIBUTION D OUT 2.5V 2C error from 40C to +85C OUT DAC V IN1 55C to +125C operating range V IN2 MUX CONTROL REG Wide operating supply range: 2.7 V to 5.5 V V SAMPLING IN3 D IN LOGIC CONTROL CAPACITOR V SCLK IN4 Inherent track-and-hold functionality RD/WR On-chip reference (2.5 V 1%) V CLOCK BALANCE CS Overtemperature indicator AGND DGND BUSY CONVST Automatic power-down at the end of a conversion Low power operation Figure 1. AD7817 Functional Block Diagram 4 W at a throughput rate of 10 SPS V DD 40 W at a throughput rate of 1 kSPS AD7818 400 W at a throughput rate of 10 kSPS OVERTEMP B A > B OTI REG TEMP Flexible serial interface SENSOR A REF CHARGE 2.5V DATA REDISTRIBUTION OUT APPLICATIONS DAC D V IN/OUT Data acquisition systems with ambient temperature IN1 MUX CONTROL SAMPLING LOGIC monitoring CAPACITOR CONTROL SCLK REG Industrial process control RD/WR V CLOCK BALANCE Automotive GENERATOR Battery charging applications AGND CONVST Figure 2. AD7818 Functional Block Diagram GENERAL DESCRIPTION The AD7817/AD7818 are 10-bit, single- and 4-channel analog-to- information, refer to the AD7817 Serial Interface section and digital converters (ADCs) with an on-chip temperature sensor that the AD7818 Serial Interface Mode section. can operate from a single 2.7 V to 5.5 V power supply. Each The AD7817 is available in a narrow body, 0.15 inch, 16-lead device contains a 9 s successive approximation converter based SOIC and a 16-lead TSSOP, and the AD7818 comes in an 8-lead around a capacitor digital-to-analog converter (DAC), an on- SOIC and an 8-lead MSOP. chip temperature sensor with an accuracy of 2C, an on-chip PRODUCT HIGHLIGHTS clock oscillator, inherent track-and-hold functionality, and an on-chip reference (2.5 V). 1. The devices have an on-chip temperature sensor that allows an accurate measurement of the ambient temperature to be The on-chip temperature sensor of the AD7817/AD7818 can made. The measurable temperature range is 55C to +125C. be accessed via Channel 0. When Channel 0 is selected and a 2. An overtemperature indicator is implemented by carrying out a conversion is initiated, the resulting ADC code at the end of the digital comparison of the ADC code for Channel 0 (temperature conversion gives a measurement of the ambient temperature with a sensor) with the contents of the on-chip overtemperature resolution of 0.25C. See the Temperature Measurement section. register. The overtemperature indicator pin goes logic low The AD7817/AD7818 have a flexible serial interface that allows when a predetermined temperature is exceeded. easy interfacing to most microcontrollers. The interface is 3. The automatic power-down feature enables the AD7817 and compatible with the Intel 8051, Motorola SPI and QSPI, and AD7818 to achieve superior power performance at slower National Semiconductors MICROWIRE protocols. For more throughput rates, that is, 40 W at 1 kSPS throughput rate. Rev. E Document Feedback Information furnished by Analog Devices is believed to be accurate and reliable. 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Technical Support www.analog.com Trademarks and registered trademarks are the property of their respective owners. 01316-001 01316-002AD7817/AD7818 Data Sheet TABLE OF CONTENTS Features .............................................................................................. 1 Converter Details ....................................................................... 12 Applications ....................................................................................... 1 Typical Connection Diagram ................................................... 12 Functional Block Diagrams ............................................................. 1 Analog Inputs ............................................................................. 12 General Description ......................................................................... 1 On-Chip Reference .................................................................... 13 Product Highlights ........................................................................... 1 ADC Transfer Function ............................................................. 13 Revision History ............................................................................... 2 Temperature Measurement ....................................................... 14 Specif icat ions ..................................................................................... 3 Temperature Measurement Error Due to Reference Error ... 14 Timing Characteristics ................................................................ 6 Self-Heating Considerations ..................................................... 14 Absolute Maximum Ratings ............................................................ 7 Operating Modes ........................................................................ 15 ESD Caution .................................................................................. 7 Power vs. Throughput................................................................ 17 Pin Configurations and Function Descriptions ........................... 8 AD7817 Serial Interface ............................................................. 17 Terminology .................................................................................... 10 AD7818 Serial Interface Mode ................................................. 18 Control Byte .................................................................................... 11 Outline Dimensions ....................................................................... 19 Circuit Information .................................................................... 12 Ordering Guide .......................................................................... 20 REVISION HISTORY 11/15Rev. D to Rev. E 9/04Rev. B to Rev. C Changes to Title, Figure 1, and Figure 2 ........................................ 1 Changes to Ordering Guide ............................................................. 6 Change to Temperature Sensor (AD7818 Only) Parameter, Changes to Operating Modes Section and Figure 16 ................ 13 Changes to Figure 17 ...................................................................... 14 Table 1 ................................................................................................ 4 Change to Power Requirements (AD7818 Only) Parameter, Changes to AD7817 Serial Interface, Read Operation Section Table 1 ................................................................................................ 5 and Figure 20 ................................................................................... 15 Changes to Figure 21 ...................................................................... 16 10/12Rev. C to Rev. D Deleted AD7816.................................................................. Universal Changes to Format ............................................................. Universal Deleted Figure 15 Renumbered Sequentially ............................ 14 Updated Outline Dimensions ....................................................... 19 Changes to Ordering Guide .......................................................... 20 Rev. E Page 2 of 20