The AD6644 is a high speed, high performance, monolithic 14-bit analog-to-digital converter (ADC). All necessary functions, including track-and-hold (TH) and reference are included on- chip to provide a complete conversion solution. The AD6644 provides CMOS-compatible digital outputs. It is the third generation in a wideband ADC family, preceded by the AD9042 (12-bit 41 MSPS) and the AD6640 (12-bit 65 MSPS, IF sampling). Designed for multichannel, multimode receivers, the AD6644 is part of the Analog Devices, Inc. new SoftCell® transceiver chipset. The AD6644 achieves 100 dB multitone, spurious-free dynamic range (SFDR) through the Nyquist band. This break- through performance eases the burden placed on multimode digital receivers (software radios) which are typically limited by the ADC. Noise performance is exceptional; typical signal-to- noise ratio is 74 dB. The AD6644 is also useful in single channel digital receivers designed for use in wide-channel bandwidth systems (CDMA, WCDMA). With oversampling, harmonics can be placed outside the analysis bandwidth. Oversampling also facilitates the use of decimation receivers (such as the AD6620), allowing the noise floor in the analysis bandwidth to be reduced. By replacing traditional analog filters with predictable digital components, modern receivers can be built using fewer RF components, resulting in decreased manufacturing costs, higher manufacturing yields, and improved reliability. The AD6644 is built on the Analog Devices high speed complementary bipolar process (XFCB) and uses an innovative, multipass circuit architecture. Units are packaged in a 52-lead plastic low profile quad flat package (LQFP) specified from – 25°C to +85°C. Product Highlights
- Guaranteed sample rate is 65 MSPS.
- Fully differential analog input stage.
- Digital outputs can be run on 3.3 V supply for easy interface to digital ASICs.
- Complete solution: reference and track-and-hold.
- Packaged in small, surface-mount, plastic, 52-lead LQFP.