SiGe LO Buffers/Splitters Simplify 3G Designs

Claimed as industry firsts, the MAX9987/MAX9988 are integrated SiGe +20dBm local oscillator (LO) buffers/splitters designed to meet the demanding requirements of 2G and 3G wireless infrastructure applications. According to the company, the ICs provide ±1dB output power variance while replacing four discrete amplifiers, a passive splitter and coupler, and dozens of biasing components. The chips are said to be ideal for cellular/GSM/DCS/PCS and UMTS base station applications where dual, high-level LO drives are required for diversity transmit and receive line-ups. Each component includes a passive two-way splitter with high-isolation input and output buffer amplifiers. This allows designers to precisely set the output power levels from +14 dBm to +20 dBm. The buffers supply an output-to-input isolation of +40 dB to prevent LO pulling and an output-to-output isolation of +30 dB to reduce branch-to-branch interference. As an added benefit, both parts feature an on-board PLL amplifier, which provides a convenient +3 dBm output for prescaler feedback. The MAX9987/MAX9988 come in 20-pin, 5 mm x 5-mm QFN packages and are priced starting at $7.95 each/1,000-up. MAXIM INTEGRATED PRODUCTS, Sunnyvale, CA. (800) 998-8800.