HMC981LP3E

The HMC981LP3E from Analog Devices is an active bias controller that automatically adjusts the gate voltage of an external amplifier to maintain a constant bias current. This device is suitable for biasing enhancement and depletion type amplifiers operating in Class-A regime, with drain voltages from 4V to 12V and drain currents up to 200mA.

It offers excellent bias stability over variations in supply, temperature, and process, eliminating the need for calibration procedures that can degrade RF performance. The HMC981LP3E is housed in a 16-lead, 3x3 mm QFN leadless package with an exposed backside pad for improved thermal characteristics. Its applications include microwave radio, VSAT, military and space systems, test instrumentation, fiber optic modulator driver biasing, CATV laser driver biasing, cellular base stations, and wireless infrastructure equipment.

Key features include automatic gate voltage adjustment, a supply voltage range of 4V to 12V, and digital voltage compatibility from 3.3V to 5V. It can control both enhancement and depletion type devices, with adjustable drain current up to 200mA. The controller also provides sink/source gate current capability and an optional internal negative voltage generation that can be disabled for external negative rail usage. A fast enable/disable function and a trigger-out output for daisy-chain power sequencing are also included.