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