8-Channel Differential DAS with 18-Bit, Bipolar, Simultaneous Sampling ADC

The AD7609 is an 18-bit, 8-channel, true differential, simultaneous sampling analog-to-digital data acquisition system (DAS). The part contains analog input clamp protection, a second-order antialiasing filter, a track-and-hold amplifier, an 18-bit charge redistribution successive approximation analog-to-digital converter (ADC), a flexible digital filter, a 2.5 V reference and reference buffer, and high speed serial and parallel interfaces.

The AD7609 operates from a single 5 V supply and can accommodate ±20 V and ±10 V true bipolar differential input signals while sampling at throughput rates up to 200 kSPS for all channels. The input clamp protection circuitry can tolerate voltages up to ±16.5 V on each analog input pin. The AD7609 has 1 MΩ analog input impedance regardless of sampling frequency. The single supply operation, on-chip filtering, and high input impedance eliminate the need for driver op amps and external bipolar supplies. The AD7609 antialiasing filter has a −3 dB cutoff frequency of 32 kHz and provides 40 dB antialias rejection when sampling at 200 kSPS. The flexible digital filter is pin driven, yields improvements in SNR, and reduces the −3 dB bandwidth.

Applications

* Power line monitoring and protection systems

* Multiphase motor control

* Instrumentation and control systems

* Multiaxis positioning systems

* Data acquisition systems (DAS)

* 8 simultaneously sampled inputs

* True differential inputs

* True bipolar analog input ranges: ±20 V, ±10 V

* Single 5 V analog supply and 2.3 V to 5.25 V VDRIVE

* Fully integrated data acquisition solution

* Analog input clamp protection

* Input buffer with 1 MΩ analog input impedance

* Second-order antialiasing analog filter

* On-chip accurate reference and reference buffer

* 18-bit ADC with 200 kSPS on all channels

* Oversampling capability with digital filter