1 Features

1• 16-Bit ADC With Integrated Analog Front-End

• 8-Channel MUX With Auto and Manual Scan

• Channel-Independent Programmable Inputs:

– ±10.24 V, ±5.12 V, ±2.56 V, ±1.28 V, ±0.64 V

– 10.24 V, 5.12 V, 2.56 V, 1.28 V

• 5-V Analog Supply: 1.65-V to 5-V I/O Supply

• Constant Resistive Input Impedance: 1 MΩ

• Input Overvoltage Protection: Up to ±20 V

• Integrated 4.096-V Reference With 6 ppm/°C Drift

• Excellent Performance:

– 500-kSPS Aggregate Throughput

– DNL: ±0.5 LSB; INL: ±0.75 LSB

– 1-ppm/°C Drift for Gain Error and Offset

– SNR: 92 dB; THD: –102 dB

– Low Power: 65 mW

• AUX Input → Direct Connection to ADC Inputs

• ALARM → High and Low Thresholds per Channel

• SPI™-Compatible Interface With Daisy-Chain

• Temperature Range: –55°C to +125°C

• TSSOP-38 Package (9.7 mm × 4.4 mm)

2 Applications

• Power Automation

• Protection Relays

• PLC Analog Input Modules

3 Description

The ADS8688AT is an 8-channel, integrated data

acquisition system based on a 16-bit successive

approximation (SAR) analog-to-digital converter

(ADC), operating at a throughput of up to 500 kSPS.

The device features integrated analog front-end

circuitry for each input channel with up to ±20-V

overvoltage protection, an 8-channel multiplexer with

automatic and manual scanning modes, and an

integrated 4.096-V reference with low temperature

drift.

Operating on a single 5-V analog supply, each input

channel can support multiple true bipolar as well as

unipolar input ranges. Each input range is softwareprogrammable

and independent for each channel,

enabling maximum system flexibility. The analog

front-end gain is accurately trimmed to ensure high

dc precision for all input ranges. The device offers a

1-MΩ constant resistive input impedance for any

selected input range, enabling direct sensor

connection to the device.

The ADS8688AT offers a simple SPI-compatible

serial interface to the digital host and also supports

daisy-chaining of multiple devices. The digital supply

operates from 1.65 V to 5.25 V, enabling direct

interface to a wide range of host controllers.