SI4735 データシートの表示（PDF） - Silicon Laboratories

部品番号

コンポーネント説明

メーカー

SI4735

Si47XX ANTENNA, SCHEMATIC, LAYOUT, AND DESIGN GUIDELINES

Silicon Laboratories 

AN383

3. Headphone Antenna for FM Receiver on FMI (Si470x/2x/3x/8x Only)

The Si470x/2x/3x FM Receiver component supports a headphone antenna interface through the FMI pin. A

headphone antenna with a length between 1.1 and 1.45 m suits the FM application very well because it is

approximately half the FM wavelength (FM wavelength is ~3 m).

3.1. Headphone Antenna Design

A typical headphone cable will contain three or more conductors. The left and right audio channels are driven by a

headphone amplifier onto left and right audio conductors and the common audio conductor is used for the audio

return path and FM antenna. Additional conductors may be used for microphone audio, switching, or other

functions, and in some applications the FM antenna will be a separate conductor within the cable. A representation

of a typical application is shown in Figure 8, “Typical Headphone Antenna Application”.

Ferrite

Beads

Antenna

Left Si47xx

Right

Figure 8. Typical Headphone Antenna Application

18

Rev. 0.8

Share Link: