The AD9866 is a mixed-signal front-end (MxFE)® IC for transceiver applications that require transmit and receive path capabilities with data rates up to 80 MSPS. The flexible digital interface, power-saving mode, and high transmit-receive isolation make the device particularly suitable for half-duplex and full-duplex applications. The digital interface is extremely flexible and can be easily interfaced with a digital backend that supports half-duplex or full-duplex data transfer, which is why the AD9866 is often used as a replacement for discrete ADC and DAC solutions. Power saving mode reduces power consumption for individual function modules or shuts down unused modules in half-duplex applications. The Serial Port Interface (SPI) allows software programming of many functional modules. The on-chip PLL clock multiplier and frequency synthesizer provide all the required internal clocks, as well as external clocks for single oscillators or clock sources.
The transmit signal path consists of a bypassable 2×/4× low-pass interpolation filter, a 12-bit TxDAC®, and a line driver. The transmit path signal bandwidth can be as high as 34 MHz at an input data rate of 80 MSPS. The TxDAC 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 line driver (with two external NPN transistors) capable of delivering more than 23 dBm of peak signal power. The transmit power can be digitally controlled with a range of 19.5 dB and a step of 0.5 dB.
The receive path consists of a programmable amplifier (RxPGA), a tunable low-pass filter (LPF), and a 12-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 30 dB, it translates to less than 3.3 nV/√Hz noise at the input. The receiver path LPF cut-off frequency can be set in the range of 15 MHz to 35 MHz or simply bypassed. The 12-bit ADC can achieve excellent dynamic performance in the range of 5 MSPS to 80 MSPS. Both RxPGA and ADC provide adjustable power consumption for power/performance optimization. The AD9866 can provide a highly integrated solution for many broadband modems. It is available in a space-saving 64-pin chip-level package and is rated for a commercial temperature range of −40°C to +85°C.
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