A2323
AUDIO AMPLIFIER
AiT Semiconductor Inc.
www.ait-ic.com
2.65W CLASS-D AUDIO POWER AMPLIFIER
The power gain of the power stage to speaker is calculated below: (RL is the speaker load impedance)
(Vo_rms)2
PL=
RL
Operation Theory
The A2323 is Dedicated TDD suppression, super low EMI, single channel, class-D audio power amplifier. The
dedicated RNS (RF-TDD Noise Suppression) technology, superior suppression in RF jamming when cellular
Phone hands-free circuit power conducting and free space radiation, can effectively preventing TDD noise
source. The A2323 dedicated EEE (Enhanced Emission Elimination) technology, reducing great level of EMI
jamming in full frequency span range, for 60cm audio cable, over more than 20dB level in FCC standard.
The A2323 internal professional timing control circuit, fully Suppressed the “Pop-Click” sound, can effectively
Erase the transient noise during power up, power down, power recovery and power off in system operation.
The A2323 internal over current protection function and thermal shutdown protection function, effectively
protected chip operation form abnormal damage condition, when abnormal condition erase, it can recovery
automatically.
The A2323 provide tiny 1.5mmX1.5mm FC-9 package, operating temperature range from -40℃ to 85℃.
RNS (RF-TDD noise Suppression)
TDD Noise origin source:
The GSM cellular phone is using the TDMA (Time Division Multiple Access) time slots sharing technology.
The time slots addressing divided each time to periodical frame, each frame divided into many time slots for
Responding signal from base station, base station transmitting prearranging scheduled time slots signal to
mobile terminal. Each of all these TDMA frames having 8 time slots, the frame periods between 4.615ms,
each time slots periods between 0.577ms.
The standard GSM cellular phone, RF power amplifier transmitted signal each 4.615ms (217Hz), it will
generated periodical burst current and strong radiation. Periodical burst current will created 217Hz power
wavering; The 900MHz or 1800MHz high frequency RF signal generated 217Hz modulation radio frequency.
The 217Hz power wavering will transmitted to audio signal channel through coupling, but the 217Hz
modulated radio frequency signal coupled to audio signal channel through radiation, if lacking better
protection mechanism, then the auditable TDD noise present, which include 217Hz noise and 217Hz
harmonica noise signal.
The RNS technology suppressed the transmission and radiation interference through a comprehensive circuit
structure, effectively increased TDD noise suppression capability.
REV3.0
- MAY 2013 RELEASED, APR 2016 UPDATED -
- 11 -
AITSEMI [ AiT Semiconductor ]
