14-Bit, 80 MSPS/105 MSPS A/D Converter

The AD6645 is a high speed, high performance, monolithic 14-bit analog-to-digital converter (ADC). All necessary functions, including track-and-hold (T/H) and reference, are included on the chip to provide a complete conversion solution. The AD6645 provides CMOS-compatible digital outputs. It is the fourth generation in a wideband ADC family, preceded by the AD9042 (12-bit, 41 MSPS), the AD6640 (12-bit, 65 MSPS, IF sampling), and the AD6644 (14-bit, 40 MSPS/65 MSPS).

Designed for multichannel, multimode receivers, the AD6645 is part of the Analog Devices, Inc., SoftCell® transceiver chipset. The AD6645 maintains 100 dB multitone, spurious-free dynamic range (SFDR) through the second Nyquist band. This breakthrough performance eases the burden placed on multimode digital receivers (software radios) that are typically limited by the ADC. Noise performance is exceptional; typical signal-to-noise ratio (SNR) is 74.5 dB through the first Nyquist band.

The AD6645 is built on the Analog Devices extra fast complementary bipolar (XFCB) process and uses an innovative, multipass circuit architecture. Units are available in a 52-lead exposed pad (TQFPEP) package specified from −40°C to +85°C at 80 MSPS and −10°C to +85°C at 105 MSPS.

Product Highlights

* IF Sampling. The AD6645 maintains outstanding ac performance up to input frequencies of 200 MHz, suitable for multicarrier 3G wideband cellular IF sampling receivers.

* Pin Compatibility. The ADC has the same footprint and pin layout as the AD6644 14-bit, 40 MSPS/65 MSPS ADC.

* SFDR Performance and Oversampling. Multitone SFDR performance of 100 dBFS can reduce the requirements of high end RF components.

Applications

* Multichannel, multimode receivers

* Base station infrastructures

* AMPS, IS-136, CDMA, GSM, W-CDMA

* Single channel digital receivers

* Antenna array processing

* Communications instrumentation

* Radars, infrared imaging

* Instrumentation

* SNR = 75 dB, fIN 15 MHz, up to 105 MSPS

* SNR = 72 dB, fIN 200 MHz, up to 105 MSPS

* SFDR = 89 dBc, fIN 70 MHz, up to 105 MSPS

* 100 dBFS multitone SFDR

* IF sampling to 200 MHz

* Sampling jitter: 0.1 ps

* 1.5 W power dissipation

* Differential analog inputs

* Pin compatible to AD6644

* Twos complement digital output format

* 3.3 V CMOS compatible

* Data-ready for output latching