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参数资料
| 型号： | TPA731DGN |
| 厂商： | TEXAS INSTRUMENTS INC |
| 元件分类： | 音频／视频放大 |
| 英文描述： | 0.7 W, 1 CHANNEL, AUDIO AMPLIFIER, PDSO8 |
| 封装： | GREEN, PLASTIC, MSOP-8 |
| 文件页数： | 8/28页 |
| 文件大小： | 792K |
| 代理商： | TPA731DGN |
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TPA731
700mW MONO LOW VOLTAGE AUDIO POWER AMPLIFIER
WITH DIFFERENTIAL INPUTS
SLOS315B JUNE 2000 REVISED OCTOBER 2002
16
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
APPLICATION INFORMATION
application schematics (continued)
It is important to note that using the additional RF resistor connected between IN+ and BYPASS causes VDD/2
to shift slightly, which could influence the THD+N performance of the amplifier. Although an additional external
op-amp could be used to buffer BYPASS from RF, tests in the lab have shown that the THD+N performance is
only minimally affected by operating in the fully differential mode as shown in Figure 27. The following sections
discuss the selection of the components used in Figures 26 and 27.
component selection
gain setting resistors, RF and RI
The gain for each audio input of the TPA731 is set by resistors RF and RI according to equation 5 for BTL mode.
(5)
BTL gain
+* 2
R
F
R
I
BTL mode operation brings about the factor 2 in the gain equation due to the inverting amplifier mirroring the
voltage swing across the load. Given that the TPA731 is a MOS amplifier, the input impedance is very high;
consequently input leakage currents are not generally a concern, although noise in the circuit increases as the
value of RF increases. In addition, a certain range of RF values is required for proper start-up operation of the
amplifier. Taken together it is recommended that the effective impedance seen by the inverting node of the
amplifier be set between 5 k
and 20 k. The effective impedance is calculated in equation 6.
(6)
Effective impedance
+
R
F
R
I
R
F )
R
I
As an example consider an input resistance of 10 k
and a feedback resistor of 50 k. The BTL gain of the
amplifier would be 10 V/V and the effective impedance at the inverting terminal would be 8.3 k
, which is well
within the recommended range.
For high performance applications, metal film resistors are recommended because they tend to have lower
noise levels than carbon resistors. For values of RF above 50 k, the amplifier tends to become unstable due
to a pole formed from RF and the inherent input capacitance of the MOS input structure. For this reason, a small
compensation capacitor of approximately 5 pF should be placed in parallel with RF when RF is greater than
50 k
. This, in effect, creates a low-pass filter network with the cutoff frequency defined in equation 7.
(7)
3 dB
fc
fc +
1
2
pR
F
C
F
For example, if RF is 100 k and CF is 5 pF, then fc is 318 kHz, which is well outside of the audio range.
相关PDF资料 |
PDF描述 |
|---|---|
| TPA731DR | 0.35 W, 1 CHANNEL, AUDIO AMPLIFIER, PDSO8 |
| TPA731D | 0.35 W, 1 CHANNEL, AUDIO AMPLIFIER, PDSO8 |
| TPA731DG4 | 0.35 W, 1 CHANNEL, AUDIO AMPLIFIER, PDSO8 |
| TPA731DRG4 | 0.35 W, 1 CHANNEL, AUDIO AMPLIFIER, PDSO8 |
| TPA731DGNRG4 | 0.7 W, 1 CHANNEL, AUDIO AMPLIFIER, PDSO8 |
相关代理商/技术参数 |
参数描述 |
|---|---|
| TPA731DGN | 制造商:Texas Instruments 功能描述:IC AMP AUDIO PWR 0.7W MONO 8MSOP 制造商:Texas Instruments 功能描述:IC, AMP AUDIO PWR 0.7W MONO 8MSOP |
| TPA731DGNG4 | 功能描述:音频放大器 Mono Diff Input Class-AB RoHS:否 制造商:STMicroelectronics 产品:General Purpose Audio Amplifiers 输出类型:Digital 输出功率: THD + 噪声: 工作电源电压:3.3 V 电源电流: 最大功率耗散: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:TQFP-64 封装:Reel |
| TPA731DGNR | 功能描述:音频放大器 Mono Diff Input Class-AB RoHS:否 制造商:STMicroelectronics 产品:General Purpose Audio Amplifiers 输出类型:Digital 输出功率: THD + 噪声: 工作电源电压:3.3 V 电源电流: 最大功率耗散: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:TQFP-64 封装:Reel |
| TPA731DGNRG4 | 功能描述:音频放大器 Mono Diff Input Class-AB RoHS:否 制造商:STMicroelectronics 产品:General Purpose Audio Amplifiers 输出类型:Digital 输出功率: THD + 噪声: 工作电源电压:3.3 V 电源电流: 最大功率耗散: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:TQFP-64 封装:Reel |
| TPA731DR | 功能描述:音频放大器 Mono Diff Input Class-AB RoHS:否 制造商:STMicroelectronics 产品:General Purpose Audio Amplifiers 输出类型:Digital 输出功率: THD + 噪声: 工作电源电压:3.3 V 电源电流: 最大功率耗散: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:TQFP-64 封装:Reel |
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