Linear Technology’s LTC5566 is a wideband, high dynamic range, dual-channel mixer with programmable variable gain IF amplifiers. The LTC5566’s input frequency range covers 300 MHz to 6 GHz, optimized and characterized at the 4G and emerging 5G bands (i.e., 3.6 and 4.5 GHz). To meet 5G sub-6 GHz requirements, the signal chain bandwidth is 400 MHz.
The LTC5566 is built on an active, double balanced mixer core with no conversion loss and excellent port-to-port isolation, which reduces external RF filtering requirements. Each mixer input contains an integrated wideband balun transformer, enabling a simple single-ended interface. Using the SPI or parallel pins, the mixers’ inputs can be digitally tuned for optimum return loss over several wide, overlapping frequency bands, ranging from 1.3 to 5.3 GHz.
The mixer has high dynamic range, with an input 1 dB compression point of +11.5 dBm and an input IP3 of +25.5 dBm at 3.6 GHz. Up to 5.8 GHz, the input IP3 remains greater than +24 dBm. The device’s integrated IF amplifier provides a maximum conversion gain of 12 dB, and each channel’s gain can be independently programmed from –3.5 to 12 dB in 0.5 dB steps using the on-chip SPI bus. The LTC5566 has 50 dB channel-to-channel isolation up to 3.6 GHz and 40 dB at 4.5 GHz. Both channels exhibit very low phase shift over the full 15.5 dB attenuation range, a critical parameter for MIMO receivers.
The LTC5566 operates from a single 3.3 V supply, drawing a nominal 384 mA with both channels on. A low power mode is available, reducing the supply current to 294 mA with a slight decrease in IP3 performance.
The mixer is rated for –40°C to +105°C case temperature operation and is offered in a 5 mm x 5 mm 32-lead plastic QFN package.
Linear Technology Corp., now part of Analog Devices, Inc.