The MAX2557A is a complete direct-conversion RF-to-bits receiver for cdma2000® 1x/EVDO femto basestations in Band Classes 0 and 1. The device has dedicated receive paths to enable monitoring forward link activities in both bands.

The unique RF-to-bits architecture of the MAX2557A integrates four LNAs with inputs/outputs internally matched to 50Ω, quadrature mixers, baseband anti-aliasing filters, programmable-gain RF and baseband amplifiers, fractional-N RF synthesizer, RF VCO, fractional-N frequency synthesizer for ADC sampling clock, and high-dynamic-range I/Q continuous-time sigma-delta ADCs. The sigma-delta modulators perform I and Q analog-to-digital conversion onto 1-bit digital streams. A programmable LVDS-like interface, with its own frac-N clock generation system, is used for the data transfer to the baseband/DSP, where the final decimation, equalization, and digital channel filtering are performed in compliance with the MAX-PHY digital section definition. Digital IP blocks are available from Maxim. The MAX2557A modes of operation are programmable by a 3-wire serial bus.

The MAX2557A is specified for operation in the extended -40°C to +85°C temperature range and is available in a 7mm x 7mm x 1.4mm fcLGA package with exposed pad (EP).

Applications

• cdma2000 1x/EVDO Femto Basestations