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We no longer stock Qwiic FM Transceiver - Si4721, but here are current alternatives in Circuitry & Internet of Things.

Qwiic FM Transceiver - Si4721

Qwiic FM Transceiver - Si4721

Discontinued

The Qwiic FM Transceiver breakout board features the Silicon Labs Si4721, which integrates both FM broadcast reception and low-power FM stereo transmission into a single IC. It can tune FM stations for listening and transmit audio on the FM band — all controllable over I2C via Qwiic connectors.

In addition to stereo audio, the Si4721 supports RDS/RBDS for transmitting and receiving text data on the FM band — the same technology commercial stations use for call signs and song titles. The board includes a 3.5 mm line-in jack for audio input, a 3.5 mm headphone output with onboard TPA6111 headphone amplifier, and a poke-home connector for antenna attachment.

Key Features

  • Silicon Labs Si4721 – Combined FM receiver and transmitter
  • FM Stereo Transmission – Low-power, standards-compliant broadcast
  • FM Reception – Full FM band tuner
  • RDS/RBDS Support – Send and receive text data over FM
  • 3.5 mm Line-In – Audio input jack for transmission
  • 3.5 mm Headphone Out – TPA6111 headphone amplifier
  • I2C Interface – Qwiic connectors, address configurable (0x11 or 0x63)
  • Antenna Connector – Two-position poke-home terminal
  • Reliable Range – Approximately 10–20 metres

Ideal For

  • FM radio projects and experimentation
  • Wireless audio streaming over short distances
  • Broadcasting sensor data or text via RDS
  • Intercom and local broadcast applications
Note: This is an extremely low-power transmitter designed for unlicensed use in most regions. However, you are responsible for complying with local RF transmission regulations. Always check your local laws before transmitting.
Maddy, co-founder of Little Bird

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