18-Bit, 2 MSPS PulSAR 15 mW ADC in QFN

The AD7986 is an 18-bit, 2 MSPS successive approximation, analog-to-digital converter (ADC). It contains a low power, high speed, 18-bit sampling ADC, an internal conversion clock, an internal reference (and buffer), error correction circuits, and a versatile serial interface port. On the rising edge of CNV, the AD7986 samples the voltage difference between the IN+ and IN− pins. The voltages on these pins usually swing in opposite phases between 0 V and VREF. It features a very high sampling rate turbo mode (TURBO = high) and a reduced power normal mode (TURBO = low) for low power applications where the power is scaled with the throughput.

In normal mode (TURBO = low), the SPI-compatible serial interface also features the ability, using the SDI input, to daisychain several ADCs on a single 3-wire bus and provide an optional busy indicator. It is compatible with 1.8 V, 2.5 V, and 2.7 V using the separate VIO supply.

The AD7986 is available in a 20-lead LFCSP with operation specified from −40°C to +85°C.

Applications

* Battery-powered equipment

* Data acquisition systems

* Medical instruments

* Seismic data acquisition systems

* 18-bit resolution with no missing codes

* Throughput: 2 MSPS (TURBO = high), 1.5 MSPS (TURBO = low)

* Low power dissipation

* 15 mW at 2 MSPS, with external reference

* 26 mW at 2 MSPS with internal reference

* INL: ±1 LSB typical, ±2.5 LSB maximum

* SNR

* 95.5 dB, with on-chip reference

* 97.0 dB, with external reference

* 4.096 V internal reference: typical drift of 10 ppm/°C

* True differential analog input voltage range: ±VREF

* 0 V to VREF with VREF up to 5.0 V

* Allows use of any input range

* See data sheet for additional features