The Si4736/7/8/9 with weather band (WB) support are the newest addition to Silicon Labs' Si473x family of high-performance broadcast audio solutions. The Si473x devices are the industry's first fully integrated, 100% CMOS AM/FM/SW/LW and WB radio receiver ICs. Offering unmatched integration and PCB space savings, the Si473x only requires two external components and less than 15 mm² of board area excluding the antenna inputs. The Si473x receiver provides the space savings and low power consumption necessary for portable devices while delivering high performance and design simplicity desired for all multi-band radio solutions.

Leveraging Silicon Labs' proven and patented Si4700/01 FM tuner's digital low intermediate frequency (low-IF) receiver architecture, the Si473x delivers superior RF performance and interference rejection in AM, FM, SW, LW and weather bands. Digital signal processing is utilized to provide optimum sound quality signal under varying reception conditions, and the high integration and complete system production test simplifies design-in, increases system quality and improves manufacturability.

The Si473x is a feature-rich solution including advanced seek algorithms, soft mute, auto-calibrated digital tuning and FM stereo processing. In addition, the Si473x provides analog or digital audio output and a programmable reference clock. The device supports I²C-compatible 2-wire control interface, and a Si4700/01 backwards-compatible 3-wire control interface.

The Si473x utilizes digital processing to achieve high fidelity, optimal performance and design flexibility. The on-chip DSP provides excellent pilot rejection, selectivity and unmatched audio performance. The on-chip microcontroller offers both the manufacturer and the end-user extensive programmability and flexibility in listening experience.

The Si4731/35/37/39 incorporates a digital processor for the European Radio Data System (RDS) and the North American Radio Broadcast Data System (RBDS) including all required symbol decoding, block synchronization, error detection and error correction functions. Using this feature, the Si4731/35/37/39 enables broadcast data such as station identification and song name to be displayed to the user.