The AD7631 is an 18-bit, charge redistribution, successive approximation register (SAR), architecture analog-to-digital converter (ADC) fabricated on Analog Devices, Inc.’s _i_CMOS high voltage process. The device is configured through hardware or via a dedicated write-only serial configuration port for input range and operating mode. The AD7631 contains a high speed 18-bit sampling ADC, an internal conversion clock, an internal reference (and buffer), error correction circuits, and both serial and parallel system interface ports. A falling edge on CNVST samples the fully differential analog inputs on IN+ and IN−. The AD7631 features four different analog input ranges. Power is scaled linearly with throughput. Operation is specified from −40°C to +85°C.
**Applications**
Process controls
High speed data acquisition
Digital signal processing
Spectrum analysis ATE
### Features and Benefits
Multiple pins/software-programmable input ranges
+5 V (10 V p-p), +10 V (20 V p-p),
±5 V (20 V p-p), ±10 V (40 V p-p)
Pins or serial SPI®-compatible input ranges/mode selection
Throughput: 250 kSPS
INL: ±1.5 LSB typical, ±2.5 LSB maximum (±9.5 ppm of FSR)
18-bit resolution with no missing codes
Dynamic range: 102.5 dB
SNR: 101 dB @ 2 kHz
THD: −112 dB @ 2 kHz
_i_CMOS® process technology
5 V internal reference: typical drift 3 ppm/°C; TEMP output
No pipeline delay (SAR architecture)
Parallel (18-/16-/8-bit bus) and serial 5 V/3.3 V interface
