AD7691: 18-bit, 250 KSPS Differential ADC.pdf

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 at 1 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 the 18-bit AD7690 and
16-bit AD7693, AD7688, and AD7687
Battery-powered equipment
Data acquisitions
Seismic data acquisition systems
Instrumentation
Medical instruments
The AD7691 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.
The part’s 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 VIO supply.
The AD7691 is housed in a 10-lead MSOP or a 10-lead LFCSP
with operation specified from −40°C to +85°C.