The AD9865 is a mixed-signal front-end (MxFE)® IC for transceiver applications requiring transmit and receive path functionality with data rates up to 80 MSPS. The flexible digital interface, power-down modes, and high transmit-receive isolation make the device ideal for half- and full-duplex applications. The digital interface is extremely flexible and enables simple interfacing with digital backends that support half- or full-duplex data transfer
AD9865It is often used to replace discrete ADC and DAC solutions. Power-down modes can reduce power consumption for individual function blocks or shut down unused modules in half-duplex applications. The serial port interface (SPI) allows software programming of many functional blocks. The on-chip PLL clock multiplier and synthesizer provide all required internal clocks, as well as external clocks for single crystal oscillators or clock sources.
The transmit signal path consists of bypassable 2×/4× low-pass interpolation filters, 10-bit TxDACs®, and line drivers. At an input data rate of 80 MSPS, the transmit path signal bandwidth can be as high as 34 MHz. The TX DAC provides a differential current output that can be directed directly to an external load or to an internal low distortion current amplifier. The current amplifier (IAMP) can be configured as a current or voltage mode linedrive(using two external NPN transistors) is capable of delivering more than 23 dBm peak signal power. The transmit power can be digitally controlled over a range of 19.5 dB in 0.5 dB steps.
The receive path consists of a programmable amplifier (RxPGA), a tunable low-pass filter (LPF), and a 10-bit ADC. The low-noise RxPGA has a programmable gain range of −12 dB to +48 dB in 1 dB steps; For gain settings above 36 dB, the input-referred noise is less than 3.0 nV/√Hz. The receive path LPF cutoff frequency can be set from 15 MHz to 35 MHz or simply bypassed. The 10-bit ADC achieves excellent dynamic performance from 5 MSPS to 80 MSPS. Both the RxPGA and ADC provide adjustable power consumption for power/performance optimization.
The AD9865 provides a highly integrated solution for many broadband modems. It is available in a space-saving 64-pin chip-scale package and is specified over the −40°C to +85°C commercial temperature range.