The HMC370LP4 is an active miniature x4 frequency multiplier utilizing InGaP GaAs HBT technology in a 4 mm x 4 mm leadless surface mount package. Power output is 0 dBm typical from a 5.0V supply voltage and varies little vs. input power, temperature and supply voltage. Suppression of undesired fundamental and sub-harmonics is >22 dBc typical with respect to output signal level. The low additive SSB phase noise of -140 dBc/Hz at 100 kHz offset helps the user maintain good system noise performance. The HMC370LP4 is ideal for use in LO multiplier chains allowing reduced parts count vs. traditional approaches.