18-Bit, 1.25 MSPS PulSAR A/D Converter

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 available in Pb-free only packages with operation specified from −40°C to +85°C.

PRODUCT HIGHLIGHTS

* Fast Throughput. The AD7643 is a 1.25MSPS, charge redistribution, 18-bit SAR ADC.

* Superior Linearity. The AD7643 has no missing 18-bit code.

* Internal Reference. The AD7643 has a 2.048 V internal reference with a typical drift of ±10 ppm/°C and an on-chip TEMP sensor.

* Single-Supply Operation. The AD7643 operates from a 2.5 V single supply.

* Serial or Parallel Interface. Versatile parallel (18-, 16-, or 8-bit bus) or 2-wire serial interface arrangement compatible with 2.5 V, 3.3 V, or 5 V logic.

APPLICATIONS

* Medical instruments

* High speed data acquisition/high dynamic data acquisition

* Digital signal processing

* Spectrum analysis

* Instrumentation

* Communications

* ATE

* Throughput: 1.25 MSPS

* INL: ±2 LSB typical, ±3 LSB max; ±8 ppm of full scale

* 18-bit resolution with no missing codes

* Dynamic range: 95.5 dB

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

* THD: −112 dB typical @ 20 kHz (VREF = 2.5 V)

* No pipeline delay (SAR architecture)

* Pb-free, 48-lead LQFP and 48-lead LFCSP

* Pin compatible with the AD7641 and other PulSAR ADC’s