GENERAL DESCRIPTION

The AD9860 and AD9862 (AD9860/AD9862) are versatile integrated mixed-signal front-ends (MxFE) that are optimized for broadband communication markets. The AD9860/AD9862 are cost effective, mixed signal solutions for wireless or wireline standards based or proprietary broadband modem systems where dynamic performance, power dissipation, cost, and size are all critical attributes. The AD9860 has 10-bit ADCs and 12-bit DACs; the AD9862 has 12-bit ADCs and 14-bit DACs. The AD9860/AD9862 receive path (Rx) consists of two channels that each include a high performance, 10-/12-bit, 64 MSPS analogto-digital converter (ADC), input buffer, Programmable Gain Amplifier (RxPGA), digital Hilbert filter, and decimation filter. The Rx can be used to receive real, diversity, or I/Q data at baseband or low IF. The input buffers provide a constant input impedance for both channels to ease impedance matching with external components (e.g., SAW filter). The RxPGA provides a 20 dB gain range for both channels. The output data bus can be multiplexed to accommodate a variety of interface types. The AD9860/AD9862 transmit path (Tx) consists of two channels that contain high performance, 12-/14-bit, 128 MSPS digital-to-analog converters (DAC), programmable gain amplifiers (TxPGA), interpolation filters, a Hilbert filter, and digital mixers for complex or real signal frequency modulation. The Tx latch and demultiplexer circuitry can process real or I/Q data. Interpolation rates of 2
and 4
are available to ease requirements on an external reconstruction filter. For single channel systems, the digital Hilbert filter can be used with an external quadrature modulator to create an image rejection architecture. The two 12-/14-bit, high performance DACs produce an output signal that can be scaled over a 20 dB range by the TxPGA. A programmable delay-locked loop (DLL) clock multiplier and integrated timing circuits enable the use of a single external reference clock or an external crystal to generate clocking for all internal blocks and also provides two external clock outputs. Additional features include a programmable sigma-delta output, four auxiliary ADC inputs and three auxiliary DAC outputs. Device programmability is facilitated by a serial port interface (SPI) combined with a register bank. The AD9860/AD9862 is available in a space saving 128-lead LQFP.