Mixed-Signal Front-End (MxFE™) Baseband
Transceiver for Broadband Applications
Receive path includes dual 12-bit, 50 MSPS analog-to-digital
converters with internal or external reference
Transmit path includes dual 12-bit, 200 MSPS digital-to-
analog converters with 1×, 2×, or 4× interpolation and
programmable gain control
Internal clock distribution block includes a programmable
phase-locked loop and timing generation circuitry,
allowing single-reference clock operation
24-pin flexible I/O data interface allows various interleaved
or noninterleaved data transfers in half-duplex mode and
interleaved data transfers in full-duplex mode
Configurable through register programmability or
optionally limited programmability through mode pins
Independent Rx and Tx power-down control pins
64-lead LFCSP package (9 mm × 9 mm footprint)
FUNCTIONAL BLOCK DIAGRAM
The AD9863 is a member of the MxFE family—a group of
integrated converters for the communications market. The
AD9863 integrates dual 12-bit analog-to-digital converters
(ADC) and dual 12-bit digital-to-analog converters (TxDAC®).
The AD9863 ADCs are optimized for ADC sampling of 50 MSPS
and less. The dual TxDACs operate at speeds up to 200 MHz
and include a bypassable 2× or 4× interpolation filter. The
AD9863 is optimized for high performance, low power, and
small form factor to provide a cost-effective solution for the
broadband communications market.
The AD9863 uses a single input clock pin (CLKIN) or two
independent clocks for the Tx path and the Rx path. The ADC
and TxDAC clocks are generated within a timing generation
block that provides user programmable options such as divide
circuits, PLL multipliers, and switches.
A flexible, bidirectional 24-bit I/O bus accommodates a variety
of custom digital back ends or open market DSPs.
In half-duplex systems, the interface supports 24-bit parallel
transfers or 12-bit interleaved transfers. In full-duplex systems,
the interface supports a 12-bit interleaved ADC bus and a
12-bit interleaved TxDAC bus. The flexible I/O bus reduces pin
count, also reducing the required package size on the AD9863
and the device to which it connects.
The AD9863 can use either mode pins or a serial programma-
ble interface (SPI) to configure the interface bus, operate the
ADC in a low power mode, configure the TxDAC interpolation
rate, and control ADC and TxDAC power-down. The SPI
provides more programmable options for both the TxDAC path
(for example, coarse and fine gain control and offset control for
channel matching) and the ADC path (for example, the internal
duty cycle stabilizer and twos complement data format).
The AD9863 is packaged in a 64-lead LFCSP (low profile, fine
pitched, chip scale package). The 64-lead LFCSP footprint is
only 9 mm × 9 mm and is less than 0.9 mm high, fitting into
such tightly spaced applications as PCMCIA cards.
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