The HMC311ST89 is a GaAs InGaP Heterojunction Bipolar Transistor (HBT) Gain Block MMIC SMT DC to 6 GHz amplifi er from Hittite Corporation. It can be used as either a cascadable 50 Ohm gain stage or to drive the LO of HMC mixers with up to +16.5 dBm output power. The HMC311ST89 offers 16 dB of gain and an output IP3 of +31.5 dBm while requiring only 54 mA from a +5V supply. The Darlington feedback pair used results in reduced sensitivity to normal process variations and yields excellent gain stability over temperature while requiring a minimal number of external bias components.