A2432
AUDIO AMPLIFIER
AiT Semiconductor Inc.
www.ait-ic.com
2X3W CLASS-D WITH DC VOLUME CONTROL AND EARPHONE OUTPUT
Fade Operation
The FADE terminal is a logic input that controls the operation of the volume control circuitry during transitions
to and from the shutdown state and during power-up.
A logic High on this terminal will set the amplifier in fade mode. During power-up or recovery from the
shutdown state, the volume is smoothly ramped up from the mute state to the desired volume set by the
voltage on the volume control terminal. A logic low on this pin disables the volume fade effect during
transitions to and from the shutdown state and during power-up. During power-up or recovery from the
shutdown state (a logic high is applied to the terminal), the transition from the mute state, -75dB, to the
desired volume setting is less than 1ms.
Filter Free Operation and Ferrite Bead Filters
A ferrite bead filter can often be used if the design is failing radiated emissions without an LC filter and the
frequency sensitive circuit is greater than 1MHz. This filter functions well for circuits that just have to pass
FCC and CE because FCC and CE only test radiated emissions greater than 30MHz. When choosing a ferrite
bead, choose one with high impedance at high frequencies, and very low impedance at low frequencies. In
addition, select a ferrite bead with adequate current rating to prevent distortion of the output signal.
Use an LC output filter if there are low frequency (< 1 MHz) EMI sensitive circuits and/or there are long leads
from amplifier to speaker.
Ferrite Bead Filter to reduce EMI
REV1.1
- MAY 2012 RELEASED, MAR 2017 UPDATED -
- 12 -
AITSEMI [ AiT Semiconductor ]
