1 Features

• 8-channel, 18-bit ADC with analog front-end:

– Dual, simultaneous sampling: 4 × 1 channels

– Constant 1MΩ input impedance front-end

• Programmable analog input ranges:

– ±12V, ±10V, ±7V, ±5V, ±3.5V, and ±2.5V

– Single-ended and differential inputs

– ±12V common-mode voltage range

– Input overvoltage protection: Up to ±18V

• User-selectable analog input bandwidth:

– 21kHz and 400kHz

• Integrated low-drift precision references

– ADC reference: 4.096V

– 2.5V reference output for external circuits

• Excellent AC and DC performance at fullthroughput:

– DNL: ±0.5LSB, INL: ±0.8LSB

– SNR: 92dB, THD: –113dB

• Power supply:

– Analog and digital: 5V and 1.8V

– Digital interface: 1.2V to 1.8V

• Temperature range: –40°C to +125°C

2 Applications

• Parametric measurement units (PMU)

• Battery cell formation and test equipment

• Data acquisition (DAQ)

3 Description

The ADS981x is an 8-channel data acquisition (DAQ)

system based on a dual, simultaneous-sampling, 18-

bit successive approximation register (SAR) analogto-

digital converter (ADC). The ADS981x features a

complete analog front-end for each channel with an

input clamp protection circuit, 1MΩ input impedance,

and a programmable gain amplifier (PGA) with

user-selectable bandwidth options. The high input

impedance allows direct connection with sensors and

transformers, thus eliminating the need for external

driver circuits. The ADS981x can be configured to

accept unipolar or bipolar inputs with up to a ±12V

common-mode voltage.

The device also features a 4.096V reference for the

ADC and a 2.5V reference output for use with external

circuits. A digital interface supporting 1.2V to 1.8V

operation enables the ADS981x to be used without

external voltage level translators.