Wideband 2 – 14 GHz mixer delivers IF bandwidth DC - 6GHz

March 08, 2016 // By Graham Prophet
LTC5548 is a double balanced mixer that operates either as an up- or downconverter with an exceptionally wide frequency range from 2 GHz to 14 GHz.

The LTC5548 features integrated balun transformers at the RF and LO ports, providing 50Ω match from 2 GHz to 13.6 GHz and from 1GHz to 12GHz at each port, respectively, while enabling single-ended operation. The IF port is capable of DC to 6 GHz, supporting wideband transmitters and receivers at the baseband. The LTC5548 has linearity of 24.4 dBm IIP3 at 5.8 GHz, and 21.4 dBm at 9 GHz. Conversion loss is 7.1 dB at 5.8 GHz and SSB noise figure is 8dB.


The mixer simplifies microwave transmitter and receiver designs with its integrated LO buffer, requiring only a 0-dBm drive, effectively eliminating an external high power LO amplifier circuit. LTC5548 has a selectable on-chip LO frequency doubler, enabling the device to use lower cost, commonly available low frequency synthesisers. The LTC5548 mixer features exceptional port-to-port isolation, minimising undesirable LO leakage, easing external filtering requirements.


The device’s performance matches a wide range of microwave applications, including broadband microwave backhaul, the emerging 5.8 GHz unlicensed band and 14 GHz LTE-Advanced broadband wireless services, satellite broadband transceivers, radar systems, X-band and Ku band transceivers, spectrum analysers, RF test equipment and satellite modems.


The LTC5548 has robust ESD handling capability of 2 kV ESD human body model (HBM) rating on all pins. The device comes in a 12-lead 3 x 2 mm plastic QFN package, providing a compact solution footprint, requiring minimal external components. The device is rated for operation from -40°C to 105°C case temperature. The mixer is powered from a single 3.3V supply, drawing a nominal supply current of 120 mA. It has an enable pin to shut down the IC. When deactivated, the device draws only 100 µA maximum standby current. The enable pin can be driven directly to turn the device on and off rapidly in less than 0.2 µsec, supporting time-division duplex (TDD) or burst mode type radios. The LTC5548 is priced starting at $9.50