Programmable Variable Gain Intermediate Frequency Amplifier (PGA) Integration
Supports up to 400MHz bandwidth for 5G in the 4G band

Linear Technology Korea announced the launch of a new wideband dual-channel mixer (product name: LTC5566 ) with dynamic range performance that integrates a programmable variable gain intermediate frequency amplifier (PGA).

This product has a very wide input frequency range of 300MHz to 6GHz and is optimized for not only the existing 4G band but also the newly emerging 3.6GHz and 4.5GHz 5G bands, as well as providing various features. In addition, it supports a bandwidth of up to 400MHz to meet the growing demand for 5G wireless access equipment below 6GHz.

The intermediate frequency (IF) amplifier integrated into this device enhances the overall power conversion gain by up to 12 dB. The gain of each channel is programmed precisely and independently in 0.5 dB increments via the on-chip SPI bus. Therefore, when each channel drives an ADC, the gains of the two channels can be easily balanced by finely controlling the gain.


▲ 300MHz~6GHz Dual Wideband Mixer with Integrated PGA

Linear explained that the dual mixer is suitable for 4G LTE-A (advanced), diversity receivers, distributed antenna systems, and SDR (software-defined radio) applications in addition to 5G.

Furthermore, the LTC5566 is built on an active dual-balanced mixer core with zero conversion loss and excellent port-to-port isolation, thereby reducing the need for external RF filtering. Each mixer input incorporates a broadband balun transformer, providing a simple single-ended interface.

Since the inputs of this mixer can be digitally adjusted using SPI or parallel pins, reflection loss can be optimized for multiple wide overlapping frequency bands in the frequency range of 1.3GHz to 5.3GHz, ensuring flexibility for use in SDR applications without adding separate components. Low frequency bands of 450MHz, 700MHz, and 900MHz are also supported.

The LTC5566 provides excellent channel-to-channel isolation of 50dB up to 3.6GHz. It still maintains high channel isolation of 40dB even at 4.5GHz. It was reported that both channels exhibit very low phase shift characteristics with a maximum attenuation range of 15.5dB.

The LTC5566 operates on a single-phase 3.3V supply voltage. When both channels are in use, this device consumes a typical supply current of 384mA. Each mixer can be turned on and off independently via separate control lines.