The MAX9987 and MAX9988 LO buffers/splitters each integrate a passive two-way power splitter with highisolation input and output buffer amplifiers. These buffers are designed to provide the high output (+14dBm to +20dBm) necessary to drive the LO inputs of high-linearity passive mixers, while offering 40dB reverse isolation to prevent LO pulling. The MAX9987 is internally matched for the cellular/GSM bands, and the MAX9988 is matched for the DCS/PCS/UMTS bands.

The typical application circuit provides a nominal +17dBm output power with ±1dB variation over supply, temperature, and input power. With two optional resistors, the output power can be precision set from +14dBm to +20dBm. The devices offer more than 30dB output-to-output port isolation, and are offered in 5mm x 5mm 20-pin thin QFN packages with exposed paddle.

Applications

• Base-Station Main and Diversity Channels
• Cellular/GSM/DCS/PCS/UMTS Base Station
• Coherent Receivers
• ISM Wireless LAN
• Local Multipoint Distribution Service
• Point-to-Point Systems
• Tx/Rx LO Drive
• Wireless Local Loop (WLL)