AD6636:  150 MSPS Wideband (Digital) Receive Signal Processor (RSP)

The AD6636 is a (Digital) Receive Signal Processor intended for direct IF sampling or highly sampled baseband radios requiring wide-bandwidth input signals. It has been optimized for the demanding filtering requirements of wideband standards like, CDMA2000, UMTS, and TD-SCDMA. The AD6636 is designed to be used as part of radio system that uses either an IF sampling ADC, or a baseband sampling ADC.

The AD6636 has the following signal processing stages: a Frequency Translator, a 5th order Cascaded Integrated Comb filter, two sets of Cascaded Fixed Coefficient Finite Impulse Response (FIR) and Half Band filters, three cascaded programmable coefficient Sum of Product FIR filters, an Interpolating Half Band Filter (LHB) and a digital Automatic Gain Control (AGC) Block. Multiple modes are supported for clocking data into and out of the chip to provide flexibility for interfacing to a wide variety of digitizers. Programming and control is accomplished via serial or microport interfaces.

The AD6636 features a fractional clock multiplier that uses the ADC clock to produce a digital down converter master clock up to 200 MHz. This internal phased-locked loop (PLL) allows optimum digital clock rates, regardless of the converter sampling rate, enabling the best possible digital signal decimation and filtering. Three 16-bit parallel output ports accommodate high data rate 3G applications. An on-chip interpolating half band filter can also be used to further increase the output rate while still allowing for very efficient filters. In addition, each channel has a digital AGC for output data scaling.