Analog Devices Announces Industry's First Broadband Mixer for Multi-Band Communication

- ADI's new single and dual-channel RF mixers, ADL5811 and ADL5812
- As an industry first, it integrates a broadband LO amplifier, programmable RF balun, IF filter, and IF amplifier.

Supports wireless infrastructure and software-based wireless applications

Analog Devices ( www.analog.com ), a global leader in high-performance semiconductors and a leader in the worldwide data converter market, announced the 'ADL5811' and 'ADL5812', broadband passive mixers for communications applications that offer the industry's highest integration rate. The ADL5811, a single-channel mixer, and the ADL5812, a dual-channel mixer, are characterized by providing excellent linearity as well as low distortion and low noise, along with broadband frequency performance. Furthermore, by integrating a broadband local oscillator amplifier, a programmable RF balun and IF filter, and a mixer core and IF amplifier that maintain high linearity, multiband, single-board receivers can be easily designed.

In addition, the ADL5811 and ADL5812 can handle a wide frequency range of 700 MHz to 2,800 MHz as a single device, and support an input IP3 (third-order intercept) of 24 dBm, an SSB noise figure of 11 dB, and a power conversion gain of 7 dB. These performances are maintained consistently within the operating frequency range. Therefore, the two broadband passive mixers are suitable for wireless infrastructure applications and software-based wireless applications, such as multiband/multistandard cellular base station receivers, broadband wireless link down converters, multimode cellular repeaters, and picocell applications.

Peter Real, Vice President of Analog Devices’ Linear and RF Group, stated, “Until now, wireless receiver designers have had to choose between active mixers, which offer excellent wideband operation performance but average Spurious-Free Dynamic Range (SFDR) performance, and passive mixers, which offer excellent SFDR performance but have a much narrower bandwidth.” He added, “Because the ADL5811 and ADL5812 offer excellent linearity, low distortion, and low noise performance, as well as perfect wideband frequency operation, designers will be able to effectively resolve the concerns they previously faced.”

The consistent high performance of the ADL5811 and ADL5812 in the 700 MHz to 2,800 MHz band is due to three technological advancements. Among these, the most emphasized aspect is the development of the LO limiting amplifier, which, unlike conventional narrowband mixers, generates a square wave with high voltage and fast rise time over a wide bandwidth without a DC current penalty.

The second feature is that the best balanced signal is supplied to the FET mixer through the direct integration of an optimized RF balun structure. Previous narrowband mixers had built-in RF baluns consisting of magnetic or transmission line transformers, which provided low losses but only average bandwidth.

The final step involves improving the structure of the passive mixer. In the existing structure, complex signals containing unwanted signals inevitably worsened the linearity of the IF amplifier. However, Analog Devices reduced unnecessary sideband amplitude delivered to the load by applying a tuning filter network with a suitable matching function according to RF and LO frequencies.

Users can easily switch between the frequencies of the ADL5811 and ADL5812 via a 3-wire SPI (serial port interface), eliminating the need for external impedance matching. Additionally, performance is optimized by providing a function to digitally control the DC bias voltage of the passive mixer gate, and in the case of the ADL5812, power consumption can be minimized by independently enabling or disabling each channel. Furthermore, the ADL5811 is suitable for multi-band implementations using Digital Pre-distortion (DPD) feedback receivers or non-diversity receiver structures.

Key Specifications and Benefits of the ADL5811 and ADL5812 Broadband Passive Mixers:
• LO limiting amplification