16-Bit, 4-Channel, 250 kSPS PulSAR ADC

The AD7682/AD7689 are 4-channel/8-channel, 16-bit, charge redistribution successive approximation register (SAR) analog-to-digital converters (ADCs) that operate from a single power supply, VDD.

The AD7682/AD7689 contain all components for use in a multichannel, low power data acquisition system, including a true 16-bit SAR ADC with no missing codes; a 4-channel (AD7682) or 8-channel (AD7689) low crosstalk multiplexer that is useful for configuring the inputs as single-ended (with or without ground sense), differential, or bipolar; an internal low drift reference (selectable 2.5 V or 4.096 V) and buffer; a temperature sensor; a selectable one-pole filter; and a sequencer that is useful when channels are continuously scanned in order.

The AD7682/AD7689 use a simple serial port interface (SPI) for writing to the configuration register and receiving conversion results. The SPI interface uses a separate supply, VIO, which is set to the host logic level. Power dissipation scales with throughput.

The AD7682/AD7689 are housed in a tiny 20-lead lead frame chip scale package (LFCSP) and 20-lead wafer level chip scale package (WLCSP) with operation specified from −40°C to +85°C. The AD7689 includes an extended temperature range model with specifications guaranteed to a maximum temperature (TMAX) of +125°C.

APPLICATIONS

* Multichannel system monitoring

* Battery-powered equipment

* Medical instruments: ECG/EKG

* Mobile communications: GPS

* Power line monitoring

* Data acquisition

* Seismic data acquisition systems

* Instrumentation

* Process control

* 16-bit resolution with no missing codes

* 4-channel (AD7682)/8-channel (AD7689) multiplexer with choice of inputs

* Unipolar single-ended

* Differential (GND sense)

* Pseudobipolar

* Throughput: 250 kSPS

* INL: ±0.4 LSB typical, ±1.5 LSB maximum (±23 ppm or FSR)

* Dynamic range: 93.8 dB

* SINAD: 92.5 dB at 20 kHz

* THD: −100 dB at 20 kHz

* Analog input range: 0 V to VREF with VREF up to VDD

* Multiple reference types

* Internal selectable 2.5 V or 4.096 V

* External buffered (up to 4.096 V)

* External (up to VDD)