1 Features

? 12-bit ADC with integrated analog front-end

? High speed: 1.25MSPS

? Software programmable input ranges:

– Bipolar differential ranges: ±12.288V, ±10.24V,

±6.144V, ±5.12V, and ±2.56V

– Unipolar differential ranges: 0V–12.288V, 0V–

10.24V, 0V–6.144V, and 0V–5.12V

? Analog supply (5V): 1.65V to 5V I/O supply

? Constant resistive input impedance ≥ 1MΩ

? Input bandwidth: 450kHz

? Input overvoltage protection: Up to ±20V

? On-chip, 4.096V reference with low drift

? Excellent performance:

– DNL: ±0.1LSB; INL: ±0.15LSB

– SNR: 74dBFS; THD: –102dB

? ALARM feature with high, low threshold

? multiSPI? interface with daisy-chain

? Extended industrial temperature range:

– –40°C to +125°C

2 Applications

? Analog input modules

? Semiconductor tests

? Servo drive control modules

3 Description

The ADS8661W is an integrated data acquisition

system based on a successive approximation (SAR)

analog-to-digital converter (ADC) topology. The

device features a high-speed, high-precision SAR

ADC, integrated differential analog front-end (AFE)

input driver circuit. The ADS8661W includes an

overvoltage protection circuit up to ±20V and an onchip

4.096V reference with extremely low temperature

drift.

The device operates on a single 5V analog supply,

but support true bipolar input ranges and unipolar

input ranges. The bipolar input ranges are ±12.288V,

±6.144V, ±10.24V, ±5.12V, and ±2.56V, and the

unipolar input ranges are from 0V to 12.288V, 10.24V,

6.144V, and 5.12V. The devices offer a high resistive

input impedance (≥ 1MΩ) irrespective of the selected

input range.

The multiSPI digital interface is backward-compatible

to the traditional SPI protocol. Additionally,

configurable features simplify interface to a wide

range of host controllers.