14-Bit, 500 kSPS PulSAR® ADC in MSOP

The AD7946 is a 14-bit, 500 kSPS, charge redistribution successive-approximation Analog-to-Digital Converter which operates from a single 5V power supply, VDD. It contains a very low power high-speed 16-bit sampling ADC with no missing codes, an internal conversion clock and a versatile serial interface port. The part also contains a low noise, wide bandwidth, very short aperture delay track/hold circuit. On the CNV rising edge, it samples an analog input IN+ between 0 V to REF with respect to a ground sense IN-. The reference voltage REF is applied externally and can be set up to the supply voltage.

Its power scales linearly with 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 supply VIO.

The AD7946 is housed in a 10-lead µSOIC or 10-lead QFN (LFCSP) with operation specified from –40°C to +85°C.

Applications

* Battery-powered equipment

* Data acquisition

* Instrumentation

* Medical instruments

* Process control

* 14-bit resolution with no missing codes

* Throughput: 500 kSPS

* INL: ±0.4 LSB typical, ±1 LSB maximum (±0.0061% of FSR)

* SINAD: 85 dB at 20 kHz

* THD: −100 dB at 20 kHz

* Pseudo differential analog input range

* 0 V to REF with REF up to VDD

* No pipeline delay

* Single-supply 5 V operation with 1.8 V/2.5 V/3 V/5 V logic interface

* Proprietary serial interface

* SPI-/QSPI™-/MICROWIRE™-/DSP-compatible

* Daisy-chain multiple ADCs and BUSY indicator

* Power dissipation

* 3.3 mW at 5 V/100 kSPS

* 3.3 μW at 5 V/100 SPS

* Standby current: 1 nA

* 10-lead MSOP (MSOP-8 size) and

* 3 mm × 3 mm LFCSP (SOT-23 size)

* Pin-for-pin compatible with the 16-bit AD7686