Analog Devices AD6641 Product Info

The AD6641 is a 250 MHz bandwidth digital predistortion (DPD) observation receiver that integrates a 12-bit 500 MSPS ADC, a 16k × 12 FIFO, and a multimode back end that allows users to retrieve the data through a serial port (SPORT), the SPI interface, a 12-bit parallel CMOS port, or a 6-bit DDR LVDS port after being stored in the integrated FIFO memory. It is optimized for outstanding dynamic performance and low power consumption and is suitable for use in telecommunications applications such as a digital predistortion observation path where wider bandwidths are desired. All necessary functions, including the sample-and-hold and voltage reference, are included on the chip to provide a complete signal conversion solution.

The on-chip FIFO allows small snapshots of time to be captured via the ADC and read back at a lower rate. This reduces the constraints of signal processing by transferring the captured data at an arbitrary time and at a much lower sample rate. The FIFO can be operated in several user-programmable modes. In the single capture mode, the ADC data is captured when signaled via the SPI port or the use of the external FILL± pins. In the continuous capture mode, the data is loaded continuously into the FIFO and the FILL± pins are used to stop this operation.

The data stored in the FIFO can be read back based on several user-selectable output modes. The DUMP pin can be asserted to output the FIFO data. The data stored in the FIFO can be accessed via a SPORT, SPI, 12-bit parallel CMOS port, or 6-bit DDR LVDS interface. The maximum output throughput supported by the AD6641 is in the 12-bit CMOS or 6-bit DDR LVDS mode and is internally limited to 1/8th of the maximum input sample rate. This corresponds to the maximum output data rate of 62.5 MHz at an input clock rate of 500 MSPS.

The ADC requires a 1.9 V analog voltage supply and a differential clock for full performance operation. Output f