TB2921HQ Toshiba, TB2921HQ Datasheet - Page 4

• Manufacturer Part Number: TB2921HQ
• Manufacturer: Toshiba

Specifications of TB2921HQ

• No. Of Channels: 4
• Package: HZIP 25-P-1.00F
• Recommended Vcc (v): 13.2
• Rl=2 Ohm: 80W x 4
• Rl=4 Ohm: 50W x 4
• Rl=8 Ohm: -
• Features/built-in Functions: 4 BTL channels, standby switch, mute, low-RON BiCD process, high-side switch
• Operating Voltage (v): 9 to 18

2. Muting Function
3. High-Side Switch
Figure 3 Muting Function
To obtain enough operation of the internal low voltage muting, a series resistor, R
kΩ or more.
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 3
and Figure 4.)
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 3.3 V from 5 V.
large pop noise basically. The low voltage muting circuit pull 200 µA current into the IC so that the effect of
the internal low voltage muting does not become enough if the R
pin. Thus, both the power amp IC and the connected external unit (the hideaway unit) can be turned
ON/OFF by using of the standby switch.
5 V
R
Additionally, as the V
Pin 25 of this device is used in concerned with V
1
C
3.3 V/5 V × 47 k = 31 k
4
22
1
and C
1 kΩ
(pin 22)
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
Mute ON/OFF
control
4
CC
Figure 4 Mute Attenuation − V
as a high-side switch which operates with the standby
−100
−120
−20
−40
−60
−80
20
0
0
V CC = 13.2 V
f = 1kHz
R L = 4 Ω
V OUT = 20dBm
0.5
1
Pin 22 control voltage: V MUTE (V)
is too small value.
1
ATT – V
1.5
1
MUTE
is determined on the basic
1
2
at pin 22 should be 47
2.5
TB2921HQ
2006-05-25
MUTE
3
(V)