ADI Announces Tiny Ultra-Wideband SiGe Mixer

3GHz to 20GHz chip with integrated LO buffer offers 23.9dBm IIP3 in 3mm x 2mm package

Analog Devices (ADI) has announced the LTC5553, a double balanced mixer providing matched bandwidth capability from 3GHz to 20GHz.

The mixer (from Linear Technology, which ADI recently acquired) can be used either as an up- or down-converter. In addition, the LTC5553 delivers high linearity performance of 23.9dBm IIP3 at 14GHz, and 21.5dBm at 17GHz.

Applications including 5G microwave backhaul, broadband wireless services, satellite broadband radios, radar systems, active antenna arrays, X and Ku band transceivers, test equipment, spectrum analysis and satellite communications.

Unlike most microwave mixers, which are made of GaAs, the LTC5553 is constructed using a very high frequency advanced SiGe BiCMOS process, which has made it possible to integrate an on-chip LO buffer amplifier and ultra-wideband microwave balun transformers.

The LO buffer requires only 0dBm input drive, effectively eliminating an external high power LO amplifier circuit.

All ports operate single-ended, 50Ω matched over their respective specified frequency range. In addition, the mixer is said to have excellent port-to-port isolation, offering -32dBm LO to RF leakage at 17GHz, thus easing external filtering requirements.

The monolithic die is flipped and soldered onto its plastic surface mount package. Bond wires are eliminated, greatly enhancing the device’s microwave frequency performance without introducing bond wire inductances

The device is rated for operation from -40degC to 105degC case temperature to support extended environmental operating temperature. The mixer is powered from a single 3.3V supply, drawing a quiescent supply current of 132mA. Additionally, the LTC5553 can be shut down via an enable pin. When deactivated, the device draws only 100µA maximum standby current. The enable pin can be driven directly to turn the device on and off rapidly in less than 0.2µs, supporting time-division duplex (TDD) or burst mode type transmitters and receivers.