Using gallium arsenide (GaAs) hetero-bipolar transistors (HBTs), Mimix Broadband has readied a monolithic microwave integrated circuit (MMIC), voltage-controlled oscillator (VCO), which uses an off-chip resonator to generate output signals from 6 to 12 GHz. The MMIC circuit consists of a linear Lange coupler based phase-shifter, a Lange coupler-based quadrature generator, a differential amplifier, a four-quadrant I/Q modulator and an output buffer differential amplifier. In addition, this device contains a frequency divider (divide-by-four)for phase-locking, frequency doubler for high-frequency output, and two additional buffer amplifiers at the oscillation frequency and at the doubled frequency. From 6 to 12 GHz, this VCO achieves +6 dBm output power and -100 dBc/Hz phase noise at 100 kHz offset, with 300 MHz instantaneous tuning range achieved through use of an external RF filter.

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This VCO, identified as 9OSC0313, is suited for wireless communications applications such as millimeter-wave point-to-point radio, local multipoint distribution services (LMDS) and SATCOM.

"This circuit offers unparalleled flexibility through the use of a 50 Ohm external bandpass filter to set the tuning range and phase noise within the 6 to 12 GHz fundamental operating range," stated Jim Harvey, CTO of Mimix Broadband. "Our patented technique allows a variety of different filter technologies to be used to trade-off tuning range versus phase noise, ranging from simple dielectric resonators for narrowband applications, to printed micro-strip filters for wideband tuning."

Mimix performs 100 percent on-wafer RF and DC testing on the 9OSC0313, as well as 100 percent visual inspection to MIL-STD-883 method 2010. The chip also has surface passivation to protect and provide a rugged part with backside via holes and gold metallization to allow either a conductive epoxy or eutectic solder die attach process.

Engineering samples are available from stock, and production quantities are available six to eight weeks ARO.