AN555

Rev. 0.2

9

3. Si483x-B/Si4820/24 SSOP Schematic and Layout

This section shows the typical schematic and layout required for optimal Si483x-B/Si4820/24 performance.

There are basically two working modes for the Si483x-B: “Volume” and “Bass/Treble” modes. Adding a pull-up

resistor of 10 k on pin2 STATION sets the chip in "Volume" mode and removing the pull-up resistor sets the chip in

"Bass/Treble" mode, as illustrated in Figure 4. When working in Bass/Treble mode, the Bass/Treble can be

controlled via two push buttons with eight levels or by a slide switch with two or three levels. When working in

“Volume” mode, tuner audio output volume can be adjusted with 2 push buttons in 32 steps (2 dB per step).

Additionally, the default power up volume level can be set with pull-up/down resistors. Compared with the Si483x-

B, Si4820/24 only works in “Volume” mode, not “Bass/Treble” mode. The following sections describe in detail the

applications circuits for different working modes.

Figure 4. Si483x-B Mode Selection