​Si4420 and Si4421 RF Transmitters​

Note: The Si4420 and Si4421 products are not available for new designs. For new designs, please use the Si4455 Sub-GHz Transceiver instead.
The Si4420/21 RF transmitters have a completely integrated PLL for easy RF design, and their rapid settling time enables fast frequency-hopping, bypassing multipath fading and interference to achieve very robust wireless links. The PLL’s high resolution allows the use of multiple channels in any of the bands. Highly stable and accurate FSK modulation is accomplished by closed-loop modulation with bit rates up to 256 kbps. In addition to the FSK modulation features, the microcontroller clock, wake-up timer, low battery detector, output power level and antenna tuning capability are also programmable through the serial interface.
*315 MHz band not available with Si4421
 
 

Features

  • Fully integrated (low BOM, easy design-in)
  • Automatic antenna tuning circuit
  • No alignment required in production
  • Fast frequency-hopping capability
  • Fast-settling, programmable, high-resolution PLL synthesizer
  • High-bit rate (up to 115.2 kbps in digital mode and 256 kbps in analog mode)
  • Stable and accurate FSK modulation with programmable deviation
  • Direct loop antenna drive
  • Programmable output power level
 
 

Applications

Technologies

  • SPI-compatible microcontroller interface
  • Power-saving sleep mode
  • Multiple event handling options for wake-up activation
Product Matrix
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Part NumberDatasheetOutput Power 868 MHzOutput Power 434 MHzSupply VoltagePackage TypeFSKDescriptionOOKSensitivityFrequency Bands
Si4420
Buy
Sample

2 dBm3 dBm2.2 - 5.4 VTSSOP16256 kbpsTRX315 MHz; 434 MHz; 868 MHz; 915 MHz
Si4421
Buy
Sample

7 dBm5 dBm2.2 - 3.8 VTSSOP16115 kbpsTRX434 MHz; 868 MHz; 915 MHz
    ​Note​: Supported for existing production, but not recommended for new designs. The Si4010 and Si4313 devices are recommended for new designs.
    ​​

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