GENERAL DESCRIPTION

The AD7643 is an 18-bit, 1.25 MSPS, charge redistribution SAR, fully differential, analog-to-digital converter (ADC) that operates from a single 2.5 V power supply. The part 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. The part has no latency and can be used in asynchronous rate applications. The AD7643 is hardware factory calibrated and tested to ensure ac parameters, such as signal-to-noise ratio (SNR), in addition to the more traditional dc parameters of gain, offset, and linearity. The AD7643 is only available in Pb-free packages with operation specified from −40°C to +85°C.

FEATURES

Throughput: 1.25 MSPS

INL: ±1.5 LSB typical, ±3 LSB maximum (±11 ppm of full scale)

18-bit resolution with no missing codes

Dynamic range: 95dB typical

SINAD: 93.5dB typical @ 20 kHz (VREF= 2.5 V)

THD: −113dB typical @ 20 kHz (VREF= 2.5 V)

2.048 V internal reference: typical drift 8ppm/°C; TEMP output

Differential input range: ±VREF(VREFup to 2.5 V)

No pipeline delay (SAR architecture)

Parallel (18-, 16-, or 8-bit bus) and serial 5 V/3.3 V/2.5 V interface

SPI®/QSPI™/MICROWIRE™/DSP compatible

Single 2.5 V supply operation

Power dissipation

65mW typical @ 1.25MSPS with internal REF

2 μW in power-down mode

Pb-free, 48-lead LQFP and 48-lead LFCSP_VQ

Pin compatible with the AD7641and other PulSAR ADC’s

APPLICATIONS

Medical instruments

High speed data acquisition/high dynamic data acquisition

Digital signal processing

Spectrum analysis

Instrumentation

Communications

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