The MAX2645 is a versatile, high-linearity, low-noise amplifier designed for 3.4GHz to 3.8GHz wireless local loop (WLL), wireless broadband access, and digital microwave radio applications. The device features an externally adjustable bias control, set with a single resistor, that allows the user to meet minimum linearity requirements while minimizing current consumption. The amplifier’s high-gain, low-noise performance and adjustable input third-order intercept (IP3) allow it to be used as a low-noise amplifier (LNA) in the receive path, a PA predriver in the transmit path, or as an LO buffer. The MAX2645 features a logic-level gain control that provides a 25dB step reduction in gain, which improves IP3 performance for operation during high input signal level conditions. Supply current is reduced from 9mA in high-gain mode to 3mA in low-gain mode. The device also includes a logic-controlled shutdown mode, which reduces supply current to 0.1µA. The MAX2645 operates from a +3V to +5.5V supply and is offered in the miniature 10-pin µMAX package (5mm × 3mm) with an exposed paddle. Its performance has been optimized for use with the MAX2683/MAX2684 3.5GHz SiGe mixers to provide a complete high-performance, front-end solution for 3.5GHz applications.
The MAX2645 is a versatile SiGe low‑noise amplifier and PA predriver covering 3.4 GHz to 3.8 GHz. It offers high‑gain and low‑gain modes, logic‑level gain control, and a shutdown mode that reduces supply current to 0.1 µA.
The device operates from a single‑supply voltage of +3 V to +5.5 V in a 10‑pin µMAX‑EP package. Detailed electrical characteristics, pin descriptions, and typical application circuits are provided for LNA, high‑IP3, and PA predriver configurations.
| Frequency Range | 3.4 GHz – 3.8 GHz |
|---|---|
| Low‑Gain Mode Gain | -9.7 dB |
| Supply Current (High‑Gain) | 9.2 mA |
| Input IP3 (High‑Gain) | +4 dBm |
The device operates from +3 V to +5.5 V.