Low-frequency sigma-delta ADCs aim for instruments

New from Analog Devices, the AD7708, AD7718 and AD7719 are all high-resolution, sigma-delta ADCs for the instrumentation and industrial sensor measurement markets.

New from Analog Devices, the AD7708, AD7718 and AD7719 are all high-resolution, sigma-delta ADCs for the instrumentation and industrial sensor measurement markets.

These are low-cost, low-power, complete analogue-front-end solutions for wide dynamic range and low-frequency applications, and they enable signal conversion directly from a transducer without the need for signal conditioning.

Specific applications benefiting from these new converters include medical electronics, industrial process control, portable instrumentation, pressure transducer, smart transmitter, weigh scale, temperature measurement and 3V data acquisition equipment.

The AD7708 is a multichannel 16bit A/D convertor.

It supports four or five fully differential inputs or eight or ten pseudodifferential inputs.

The AD7718 is a 24bit version and is pin-, function- and software-compatible with the AD7708.

The AD7719 is a dual sigma-delta ADC that integrates a 24bit and a 16bit ADC on the same device.

This allows simultaneous conversion of two signals and increases throughput in a multiplexed application.

Also included on-chip are switchable current sources, low-side power switches and a temperature sensor.

All three ADCs consume 2mA at 3V in the normal mode and less than 10uA in the power-down mode.

Evaluation boards are available for each convertor.

The AD7708 costs $3.98, the AD7718 costs $5.24 and the AD7719 costs $8.76, all in 1000-piece quantities.

Each is available in 28-lead SOIC and TSSOP packages.

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