tb2946hq TOSHIBA Semiconductor CORPORATION, tb2946hq Datasheet - Page 7

• Manufacturer Part Number: tb2946hq
• Description: 49 W ? 4-ch Btl Audio Power Ic
• Manufacturer: TOSHIBA Semiconductor CORPORATION

5. Pop Noise Suppression
6. External Component Constants
Component
C1
C2
C3
C4
C5
C6
Since the TB2946HQ 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.
Caution for use : We propose that C2 value are adjustable from 10μF to 47μF at the turn-on timing.
Recommended
3900 μF
0.22 μF
0.1 μF
Value
10 μF
1 μF
1 μF
To eliminate DC
To reduce ripple
To provide
sufficient
oscillation margin
To reduce pop
noise
Ripple filter
Common
reference voltage
for all input
Purpose
Cut-off frequency is
increased.
Powering on/off is faster.
Reduces noise and provides sufficient oscillation margin
High pop noise. Duration until
mute function is turned on/off
is short.
Power supply humming and ripple filtering.
Pop noise is suppressed when C1: C6 = 1:4.
recommended value
When lower than
7
Effects
Cut-off frequency is reduced.
Powering on/off is slower.
Low pop noise. Duration until
mute function is turned on/off
is long.
recommended value
When higher than
TB2946HQ
Pop noise is
generated
when V
turned on.
Pop noise is
generated
when V
turned on.
2009-01-29
Notes
CC
CC
is
is