GENERAL DESCRIPTION

The AD7707 is a complete analog front end for low frequency measurement applications. This three-channel device can accept either low level input signals directly from a transducer or high level (±10 V) signals and produce a serial digital output. It employs a sigma-delta conversion technique to realize up to

16 bits of no missing codes performance. The selected input signal is applied to a proprietary programmable gain front end based around an analog modulator. The modulator output is processed by an on-chip digital filter. The first notch of this digital filter can be programmed via an on-chip control register allowing adjustment of the filter cutoff and output update rate.

FEATURES

Charge Balancing ADC

  16 Bits No Missing Codes

  0.003% Nonlinearity

High Level (610 V) and Low Level (610 mV) Input Channels

True Bipolar 6100 mV Capability on Low Level Input  Channels Without Requiring Charge Pumps

Programmable Gain Front End Gains from 1 to 128

Three-Wire Serial Interface

  SPI™, QSPI™, MICROWIRE™ and DSP Compatible

  Schmitt Trigger Input on SCLK

Ability to Buffer the Analog Input

2.7 V to 3.3 V or 4.75 V to 5.25 V Operation

Power Dissipation 1 mW max @ 3␣ V

Standby Current 8 mA max

20-Lead SOIC and TSSOP Packages