Microwave Journal
www.microwavejournal.com/articles/17263-high-linearity-downconverting-mixer-covers-4-6ghz-rf-frequency-range-

Linear Technology introduces high linearity downconverting mixer

March 28, 2012

Linear Technology announces the LTC5544, a 4 GHz to 6 GHz high dynamic range downconverting mixer. The LTC5544 mixer offers high linearity with 25.9 dBm Input Third-Order Intercept (IIP3), high conversion gain of 7.4 dB owing to its integrated IF amplifier, and a noise figure of 11.3 dB. These performance characteristics enable excellent dynamic range performance for both main receivers and digital pre-distortion receivers. Moreover, the LTC5544’s RF input can withstand strong interference signals without significantly degrading its noise figure, thus preserving receiver sensitivity and enhancing robustness. The LTC5544 operates on a single 3.3 V supply without compromising performance, while keeping power consumption to a minimum.

The LTC5544’s 6 GHz reach is ideally suited for wireless systems such as point-to-point broadband microwave links, 5 GHz license-free band WiMAX radios, satellite receivers, radar systems, avionics, public safety radios and RF test systems.

The LTC5544 incorporates an on-chip integrated high gain IF amplifier capable of supporting IF frequencies up to 1 GHz. Also integrated are an LO buffer along with two RF balun transformers. They enable the RF and LO inputs to operate single-ended and with 50Ω matching. The LO input requires only +2 dBm drive level. These features simplify design and require fewer external components, resulting in a smaller solution size.

The LTC5544 operates on a single 3.3 V supply, drawing 194 mA of current. The LTC5544 has a power-down feature with 0.6µs turn-on and turn-off time, supporting Burst Mode® operation or TDD (time division duplexed) systems. When disabled, the device consumes a maximum of 500 µA. The LTC5544 is offered in a 16-lead, 4 x 4 mm plastic QFN package and is available immediately from stock.