TB2902HQ Toshiba, TB2902HQ Datasheet - Page 3

• Manufacturer Part Number: TB2902HQ
• Manufacturer: Toshiba

Specifications of TB2902HQ

• No. Of Channels: 4
• Package: HZIP 25-P-1.00F
• Recommended Vcc (v): 13.2
• Rl=2 Ohm: 70W x 4
• Rl=4 Ohm: 43W x 4
• Rl=8 Ohm: -
• Features/built-in Functions: 4 BTL channels, internal standby/mute, BiCD process, I2C self-diagnosis, tweeter diagnostics
• Operating Voltage (v): 9 to 18

Caution and Application Information
channel.)
1. Voltage Gain Adjustment
2. Muting Time Constant and Pop Noise Suppression when V
Caution on the use of the muting function
software). However, this feature makes possible space and cost saving.
dynamic range is reduced as the output of Amp.1 is attenuated.
constant to suppress the pop noise. The larger
value capacitor is used, the lower pop noise
becomes but the longer the muting time from the
mute ON command sent to muting an output
sound actually. The charge period, which makes
the delay of muting after "Mute On" command is
written, is MIN=30msec, MAX=180msec in case
of C4 (Pin 16) = 1 uF, Vcc=9 to 18V and Tj = -40
to 150 degrees condition.
voltage muting operates to eliminate the large
pop noise basically.
is not enough in such a case, make this pin 16 set
at low: 5 V and less by external circuit for more
effective to suppress the pop noise.
is muted, so that it is necessary to send a “mute off” command to change from this condition to play mode.
function is determined by the value of C4, the designer should take into account the possible generation of
pop noise during switching operations. The pop noise which is generated when the power or muting
function is turned ON/OFF will vary according to the time constant set by capacitor C4 value.
time interval when the voltage on pin 16 is falling.
sent from µController while the voltage at pin 16 is rising.
If the effect of the internal low voltage muting
In this case, this pin 16 has to be released from setting at low before going back to play mode.
Additionally, the initial state after turning the amplifier “ON” or after turning stand by “off” by I
The audio muting function is enabled when pin 16 is not set Low. While the time constant of the muting
However, the pop noise may become apparent as a “peaky” sound if the mute ON or OFF command is
This IC has no NF (negative feedback) Pins. Therefore, the voltage gain can not be adjusted (except by
The amplifier gain, G
Therefore, the total voltage gain is decided by expression below.
In the case when G
The capacitor C4 at pin 16 is for muting time
As the V
In the case when C4 value is large and the time constant is long, pop noise will be suppressed during the
The voltage gain of amp.1: G
The voltage gain of amp.2A, B: G
The voltage gain of BTL connection: G
G
V
= G
CC
V1
is rapidly falling, the IC internal low
+ G
V2
V
+ G
= 12dB selected via I
V
= 26dB, is calculated using the expression below:
V (BTL)
Input
Figure 1 Block Diagram
= 0 + 20 + 6 = 26dB
V1
= 0dB
V2
Amp. 1
= 20dB
(description is made referring only on the single
V (BTL)
2
C, G
3
V1
= 6dB
changed from 0dB to −14dB so that the output
Amp. 2A
Figure 2 Pin 16 Muting Circuit
Amp. 2B
16
CC
Rapidly Falls
From low voltage
muting circuit
To mute circuit
TB2902HQ
2004-08-18
(pin 16)
2
C Bus