TB2936HQ Datasheet, PDF (8/20 Pages) Toshiba Semiconductor – 49 W x 4-ch BTL Audio Power IC

TB2936HQ
6. Pop Noise Suppression
Since the TB2936HQ uses the AC-GND pin (pin 16) as the common input reference voltage pin for all
amplifiers, the ratio of the input capacitance (C1) to the AC-to-GND capacitance (C6) should be 1:4.
Also, if power is removed before C1 and C6 are completely charged, pop noise will be generated because of
unbalanced DC currents.
To avoid this problem, it is recommended to use a larger capacitor as C2 to increase the charging times of C1
and C6. Note, however, that C2 also affects the time required from power-on to audio output.
The pop noise generated by the muting and unmuting of the audio output varies with the time constant of
C4. A larger capacitance reduces the pop noise, but increases the time from when the mute control signal is
applied to C4 to when the mute function is enabled.
7. External Component Constants
Component
Recommended
Value
Purpose
Effects
When lower than
recommended value
When higher than
recommended value
Notes
C1
0.22 μF
To eliminate DC
Cut-off frequency is
increased.
Cut-off frequency is reduced.
Pop noise is
generated
when V_CC is
turned on.
C2
10 μF
To reduce ripple Powering on/off is faster.
Powering on/off is slower.
To provide
C3
0.1 μF
sufficient
Reduces noise and provides sufficient oscillation margin
oscillation margin
C4
1 μF
To reduce pop
noise
High pop noise. Duration until Low pop noise. Duration until
mute function is turned on/off mute function is turned on/off
is short.
is long.
C5
3900 μF Ripple filter
Power supply humming and ripple filtering.
Common
C6
1 μF
reference voltage Pop noise is suppressed when C1: C6 = 1:4.
for all input
Pop noise is
generated
when V_CC is
turned on.
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2009-02-04