FM receivers support embedded antennas - 14 May 2008 - NuVision Electronics

FM receivers support embedded antennas
14 May 2008, Telecoms, Datacoms, Wireless, IoT

Silicon Laboratories has expanded its broadcast audio portfolio to include four new FM receivers. The new additions include full-featured devices with embedded antenna support to enable FM radio reception without an external wired headset and small devices for space-constrained applications. The new FM receivers make it easy to add FM functionality to an array of applications from low-cost handsets and MP3 players, where small size and low power are imperative, to standalone FM radios, PCs, PDAs, smartphones and USB FM receivers.

The new Si4704 and Si4705 incorporate all of the features found in Silicon Laboratories' CMOS Si4700 FM tuner family and are said to be the industry's first to support an embedded antenna. The patent-pending tunable resonance circuit incorporated on-chip provides optimal signal reception and excellent sound quality with a short embedded antenna, such as a wire or PCB trace that can be integrated inside the end product casing, enabling FM radio to be added to any portable device without the need for an external headphone cable. This enables a truly wireless music experience for FM recording, clock radios and FM over speaker applications where a headset is not required. It also complements products with integrated Bluetooth technology by allowing consumers to listen to radio over wireless headsets without having to attach a headphone cable to their portable receiver.

In addition, the Si4705 provides a digital audio interface that allows easy recording of FM radio without the need for external analog-to-digital converters, saving power, cost and board space. Requiring only 15 mm² of board space, the devices are layout-compatible with Silicon Labs' Si4710/11/12/13 FM transmitter, Si4720/21 FM transceiver and Si4730/31 AM/FM receiver, enabling one common platform among multiple designs. Both devices provide coverage of the expanded worldwide FM frequency band from 64 to 108 MHz.

The new third-generation Si4708 and Si4709 FM receivers require only 8 mm² of board space and are packaged in a 2,5 x 2,5 mm QFN package that is easy to assemble and forms robust solder joints without requiring any underfill or mechanical reinforcement. In addition to the small size, these receivers offer advanced FM seek algorithms, allowing consumers to more quickly seek and lock to available FM stations. The devices provide excellent selectivity using low-IF receiver architecture. The Si4709 also provides RDS functionality.

A full reference board with complete schematics, layout files and a robust software development environment is available to customers to facilitate evaluation and design.