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參數(shù)資料
| 型號： | TB2903HQ |
| 元件分類： | 音頻／視頻放大 |
| 英文描述： | 29 W, 4 CHANNEL, AUDIO AMPLIFIER, PZFM25 |
| 封裝： | 1 MM PITCH, PLASTIC, HZIP-25 |
| 文件頁數(shù)： | 9/15頁 |
| 文件大?。?/td> | 343K |
| 代理商： | TB2903HQ |
TB2903HQ
2004-07-25
3
Caution and Application Method
(Description is made only on the single channel.)
1.
Voltage Gain Adjustment
This IC has no NF (negative feedback) Pins. Therefore, the voltage gain can not be adjusted, but it makes
the device a space and total costs saver.
The voltage gain of amp.1
: GV1 = 0dB
The voltage gain of amp.2A, B
: GV2 = 20dB
The voltage gain of BTL connection: GV (BTL) = 6dB
Therefore, the total voltage gain is decided by expression below.
GV = GV1 + GV2 + GV (BTL) = 0 + 20 + 6 = 26dB
2.
Standby SW Function (pin 4)
By means of controlling pin 4 (standby pin) to
High and Low, the power supply can be set to ON
and OFF. The threshold voltage of pin 4 is set at
about 3VBE (typ.), and the power supply current is
about 2
A (typ.) in the standby state.
Control Voltage of Pin 4: VSB
Standby
Power
VSB (V)
ON
OFF
0~1.5
OFF
ON
3.5~6 V
When changing the time constant of pin 4, check the
pop noise.
Advantage of Standby SW
(1)
Since VCC can directly be controlled to ON or OFF by the microcomputer, the switching relay can be
omitted.
(2)
Since the control current is microscopic, the switching relay of small current capacity is satisfactory
for switching.
Amp. 1
Input
Amp. 2A
Amp. 2B
Figure 1
Block Diagram
Figure 2 With pin 4 set to High,
Power is turned ON
ON
4
OFF
10 k
to BIAS
CUTTING CIRCUIT
≈ 2 VBE
VCC
Power
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