GENERAL DESCRIPTION

The AD76911 is an 18-bit, charge redistribution, successive approximation, analog-to-digital converter (ADC) that operates from a single power supply, VDD, between 2.3 V and 5 V. 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 phases between 0 V and REF. The reference voltage, REF, is applied externally and can be set up to the supply voltage.

FEATURES

18-bit resolution with no missing codes

Throughput: 250 kSPS

INL: ±0.75 LSB typical, ±1.5 LSB maximum (±6 ppm of FSR)

Dynamic range: 102 dB typical at 250 kSPS

Oversampled dynamic range: 125 dB at1 kSPS

Noise-free code resolution: 20 bits at 1 kSPS

Effective resolution: 22.7 bits at 1 kSPS

SINAD: 101.5 dB typical at 1 kHz

THD: −125 dB typical at 1 kHz

True differential analog input range: ±VREF

0 V to VREF with VREF up to VDD on both inputs

No pipeline delay

Single-supply 2.3 V to 5 V operation with

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

Proprietary serial interface

SPI/QSPI/MICROWIRE™/DSP compatible

Ability to daisy-chain multiple ADCs

Optional busy indicator feature

Power dissipation

1.35 mW at 2.5 V/100 kSPS, 4 mW at 5 V/100 kSPS

1.4 µW at 2.5 V/100 SPS

Standby current: 1 nA

10-lead packages: MSOP (MSOP-8 size) and

3 mm × 3 mm LFCSP (SOT-23 size)

Pin-for-pin compatible with the18-bit AD7690 and

16-bit AD7693, AD7688, and AD7687

APPLICATIONS

Battery-powered equipment

Data acquisitions

Seismic data acquisition systems

Instrumentation

Medical instruments