GENERAL DESCRIPTION

The AD7688 is a 16-bit, charge redistribution, successive approximation, analog-to-digital converter (ADC) that operates from a single 5 V power supply, VDD. It contains a 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, short aperture delay track-and-hold circuit. On the CNV rising edge,

it samples the voltage difference between IN+ and IN− pins. The voltages on these pins usually 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.

FEATURES

16-bit resolution with no missing codes

Throughput: 500 kSPS

INL: ±0.4 LSB typ, ±1.5 LSB max (±23 ppm of FSR)

Dynamic range: 96.5 dB

SNR: 95.5 dB @ 20 kHz

THD: −118 dB @ 20 kHz

True differential analog input range

±VREF

0 V to VREFwith VREFup to VDD on both inputs

No pipeline delay

Single-supply 5 V operation with

1.8 V/2.5 V/3 V/5 V logic interface

Serial interface SPI®/QSPI™/MICROWIRE™/DSP-compatible

Daisy-chain multiple ADCs and BUSY indicator

Power dissipation

3.75 mW @ 5 V/100 kSPS

3.75 μW @ 5 V/100 SPS

Standby current: 1 nA

10-lead MSOP (MSOP-8 size) and

3 mm × 3 mm QFN (LFCSP) (SOT-23 size)

Pin-for-pin compatible with AD7685, AD7686, and AD7687

APPLICATIONS

Battery-powered equipment

Data acquisitions

Instrumentation

Medical instruments

Process controls