The MAX9989 and MAX9990 LO buffers 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 MAX9989 is internally matched for the cellular/GSM bands, and the MAX9990 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 35dB main driver output to PLL amp output isolation. Each device is offered in a 5mm x 5mm 20-pin thin QFN package with exposed paddle.
Key Features
Applications/Uses
±1dB Output Power Variation
+14dBm to +20dBm Adjustable Output Power
40dB Reverse Isolation
Better Than 35dB Main Driver Output to PLL Amp Output Isolation
Low Output Noise: -170dBc/Hz at +17dBm
110mA Supply Current at +17dBm
ESD Protection
Isolated PLL Output (+3dBm)
Cellular/GSM/DCS/PCS/UMTS Base Station Tx/Rx LO Drive
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