MAX9987/MAX9988 is a MAXIM's RF transceiver. The device integrates a passive two-way power splitter with high-isolation 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 resis- tors, 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 ✕ 5mm 20-pin thin QFN packages with exposed paddle.
The MAX9987 and MAX9988 LO buffers/splitters integrate a passive two‑way power splitter with high‑isolation input and output buffer amplifiers. They provide high output power for driving LO inputs of high‑linearity mixers and feature adjustable output power from +14 dBm to +20 dBm.
Key specifications include a supply voltage range of 4.75 V‑5.25 V, operating frequency bands of 700‑1100 MHz (MAX9987) and 1500‑2200 MHz (MAX9988), supply currents up to 221 mA (MAX9987) and 229 mA (MAX9988), and reverse isolation of 40 dB. The devices are offered in a 5 mm × 5 mm 20‑pin thin QFN package with an exposed paddle.
| Output Power Range | +14 dBm to +20 dBm |
|---|---|
| Supply Voltage | 4.75 V – 5.25 V |
| Operating Frequency (MAX9987) | 700 MHz – 1100 MHz |
| Operating Frequency (MAX9988) | 1500 MHz – 2200 MHz |
| Reverse Isolation | 40 dB |
| Output‑to‑Output Isolation | >30 dB |
| Output Noise | -170 dBc/Hz at +17 dBm |
Both devices can be set to deliver output power from +14 dBm up to +20 dBm.
The recommended supply voltage range is 4.75 V to 5.25 V.
The MAX9987 operates from 700 MHz to 1100 MHz, while the MAX9988 operates from 1500 MHz to 2200 MHz.
They provide 40 dB of reverse isolation to prevent LO pulling.