Multiband, Multimode RF-to-Bits CDMA Femto-Basestation Radio Receiver

Industry's First Femto-Basestation Chipset for 1x/EVDO cdma2000 Applications with Digital Interface

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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).
MAX2557A: Pin Configuration/Block Diagram MAX2557A: Pin Configuration/Block Diagram Enlarge+

Key Features

  • Complete RF-to-Digital-Bits Radio Receiver Subsystem
  • Supports
    • cdma2000 1x/EVDO Band Class 0 and 1 Reverse Link
    • cdma2000 1x/EVDO Band Class 0 and 1 Forward Link Monitoring
  • TS25.104 Compliant
  • Compatible with UMTS1900, UMTS850, and CDMA Interference Environments
  • High-Dynamic-Range Continuous-Time Sigma-Delta ADCs Allow Simple AGC Implementation with Switched Gain States
  • MAX-PHY Digital Rx Interface with Single-Bit I/Q Bitstream, No Analog Signals
  • On-Chip Fractional-N Frequency Synthesizers for LO and Sampling Clock Generation
  • Dual-Buffered Reference Outputs to Drive Transmit IC and Baseband DSP
  • Programmable Rail-to-Rail GPO Pins Controlled by Serial Interface for External Component Control
  • Operation Controlled Entirely by 3-Wire Serial Interface, No Analog Control Signals Necessary


  • cdma2000 1x/EVDO Femto Basestations

Technical Documents

Tutorial 5100 General Layout Guidelines for RF and Mixed-Signal PCBs
Request Reliability Report for: MAX2557A 
Device   Fab Process   Technology   Sample size   Rejects   FIT at 25°C   FIT at 55°C   Material Composition  

Note : The failure rates are summarized by technology and mapped to the associated material part numbers. The failure rates are highly dependent on the number of units tested.

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