TB2904HQ Toshiba, TB2904HQ Datasheet - Page 4

• Manufacturer Part Number: TB2904HQ
• Manufacturer: Toshiba

Specifications of TB2904HQ

• No. Of Channels: 4
• Package: HZIP 25-P-1.00F
• Recommended Vcc (v): 13.2
• Rl=2 Ohm: Not Supported
• Rl=4 Ohm: 45W x 4
• Rl=8 Ohm: -
• Features/built-in Functions: 4 BTL channels, standby switch, mute, BiCD process, offset detection
• Operating Voltage (v): 9 to 18

3. Muting Function
Figure 4 Muting Function
Audio muting function is enabled when pin 22 is Low. When the time constant of the muting function is
determined by R
the power or muting function is turned ON/OFF, will vary according to the time constant. (Refer to Figure 4
and Figure 5.)
The pin 22 is designed to operate off 5 V so that the outside pull-up resistor R
of this value:
ex) When control voltage is changed in to 6 V from 5 V.
large pop noise basically.
voltage muting does not become enough if the R
47 kΩ or more.
5 V
The low voltage muting circuit pull 200 µA current into the IC so that the effect of the internal low
Additionally, as the V
To obtain enough operation of the internal low voltage muting, a series resistor, R
R
1
6 V/5 V × 47 k = 56 k
C
4
22
1
and C
1 kΩ
Stand-By
(pin 22)
V
CC
4
CC
,
it should take into account the pop noise. The pop noise, which is generated when
is rapidly falling, the IC internal low voltage muting operates to eliminate the
Small current capacity switch
Large current capacity switch
Mute ON/OFF
control
V
CC
Battery
– Standby Switch Method –
Battery
– Conventional Method –
Figure 3
1
4
is too small value.
Figure 5 Mute Attenuation − V
−100
−120
From microcomputer
−20
−40
−60
−80
20
0
0
V
V CC = 13.2 V
f = 1 kHz
R L = 4 Ω
V out = 7.75 Vrms
(20dBm)
Stand-By
CC
0.5
Pin 22 control voltage: V
1
V
Relay
CC
ATT – V
1.5
1
is determined on the basic
MUTE
2
From
microcomputer
Battery
Battery
MUTE
1
at pin 22 should be
2.5
TB2904HQ(o)
(V)
3
2004-03-26
MUTE
3.5
(V)