18-Bit, 1.5 LSB INL, 400 SPS PSAR Differential ADC in MSOP/QFN

The AD7690 is an 18-bit, successive approximation, analog-to-digital converter (ADC) that operates from a single power supply, VDD. It contains a low power, high speed, 18-bit sampling ADC with no missing codes, an internal conversion clock, and a versatile serial interface port. On the CNV rising edge, it samples the voltage difference between the IN+ and IN− pins. The voltages on these pins swing in opposite phase between 0 V and REF. The reference voltage, REF, is applied externally and can be set up to the supply voltage.

The power of the AD7690 scales linearly with the throughput.

The SPI-compatible serial interface also features the ability, using the SDI input, to daisy-chain several ADCs on a single, 3-wire bus and provides an optional busy indicator. It is compatible with 1.8 V, 2.5 V, 3 V, or 5 V logic, using the separate VIO supply.

The AD7690 is housed in a 10-lead MSOP or a 10-lead QFN (LFCSP) with operation specified from −40°C to +85°C.

APPLICATIONS

* Battery-powered equipment

* Data acquisition

* Seismic data acquisition systems

* DVMs

* Instrumentation

* Medical instruments

* 18-bit resolution with no missing codes

* Throughput: 400 kSPS

* INL: ±0.75 LSB typ, ±1.5 LSB max

(±6 ppm of FSR)

* Dynamic range: 102 dB @ 400 kSPS

* Oversampled dynamic range: 125 dB @ 1 kSPS

* Noise-free code resolution: 20 bits @ 1 kSPS

* Effective resolution: 22.7 bits @ 1 kSPS