参数资料
型号: TPA6112A2DGQR
厂商: TEXAS INSTRUMENTS INC
元件分类: 音频/视频放大
英文描述: 0.15 W, 2 CHANNEL, AUDIO AMPLIFIER, PDSO10
封装: GREEN, PLASTIC, MSOP-10
文件页数: 6/22页
文件大小: 701K
代理商: TPA6112A2DGQR
www.ti.com
APPLICATION INFORMATION
GAIN SETTING RESISTORS, R
f and Ri
f
c(highpass) +
1
2p R
i
C
i
(4)
Gain + *
R
f
R
i
(1)
C
i +
1
2p R
i fc(highpass)
(5)
Effective Impedance +
R
fRi
R
f ) Ri
(2)
POWER SUPPLY DECOUPLING, C
(S)
f
c(lowpass) +
1
2p R
f CF
(3)
INPUT CAPACITOR, C
i
TPA6112A2
SLOS342A – DECEMBER 2000 – REVISED SEPTEMBER 2004
The gain for the TPA6112A2 is set by resistors Rf
The value of Ci directly affects the bass (low fre-
and Ri according to Equation 1.
quency) performance of the circuit. Consider the
example where Ri is 20 k and the specification calls
for a flat bass response down to 20 Hz. Equation 4 is
reconfigured as Equation 5.
Given that the TPA6112A2 is a MOS amplifier, the
input impedance is very high. Consequently input
leakage currents are not generally a concern. How-
In this example, Ci is 0.40 F, so one would likely
ever, noise in the circuit increases as the value of Rf
choose a value in the range of 0.47 F to 1 F. A
increases. In addition, a certain range of Rf values is
further consideration for this capacitor is the leakage
required for proper start-up operation of the amplifier.
path from the input source through the input network
Considering these factors, it is recommended that the
formed by Ri, Ci, and the feedback resistor (Rf) to the
effective impedance seen by the inverting node of the
load. This leakage current creates a dc offset voltage
amplifier be set between 5 k
and 20 k. The
at the input to the amplifier that reduces useful
effective impedance is calculated using Equation 2.
headroom, especially in high-gain applications (gain
>10). For this reason a low-leakage tantalum or
ceramic capacitor is the best choice. When polarized
capacitors are used, connect the positive side of the
capacitor to the amplifier input in most applications.
For example, if the input resistance is 20 k
and the
The dc level there is held at VDD/2—likely higher than
feedback resistor is 20 k
, the gain of the amplifier is
the source dc level. It is important to confirm the
-1, and the effective impedance at the inverting
capacitor polarity in the application.
terminal is 10 k
, a value within the recommended
range.
For high performance applications, metal-film re-
The TPA6112A2 is a high-performance CMOS audio
sistors are recommended because they tend to have
amplifier that requires adequate power-supply de-
lower noise levels than carbon resistors. For values
coupling to minimize the output total harmonic distor-
of Rf above 50 k, the amplifier tends to become
tion (THD). Power-supply decoupling also prevents
unstable due to a pole formed from Rf and the
oscillations when long lead lengths are used between
inherent input capacitance of the MOS input struc-
the amplifier and the speaker. The optimum decoup-
ture. For this reason, a small compensation capacitor
ling is achieved by using two capacitors of different
of approximately 5 pF should be placed in parallel
types that target different types of noise on the power
with Rf. This, in effect, creates a low-pass filter
supply leads. For higher frequency transients, spikes,
network
with
the
cutoff
frequency
defined
by
or digital hash on the line, a good low equival-
Equation 3.
ent-series-resistance (ESR) ceramic capacitor, typi-
cally 0.1 F, placed as close as possible to the
device
VDD
lead,
works
best.
For
filtering
lower-frequency noise signals, a larger aluminum
For example, if Rf is 100 k and CF is 5 pF then
electrolytic capacitor of 10 F or greater placed near
fc(lowpass) is 318 kHz, which is well outside the audio
the power amplifier is recommended.
range.
In the typical application, an input capacitor, Ci, is
required to allow the amplifier to bias the input signal
to the proper dc level for optimum operation. In this
case, Ci and Ri form a high-pass filter with the corner
frequency determined in Equation 4.
14
相关PDF资料
PDF描述
TPA6112A2DGQ 0.15 W, 2 CHANNEL, AUDIO AMPLIFIER, PDSO10
TPA6112A2DGQRG4 0.15 W, 2 CHANNEL, AUDIO AMPLIFIER, PDSO10
TPA6112A2DGQG4 0.15 W, 2 CHANNEL, AUDIO AMPLIFIER, PDSO10
TPA6120A2DWPRG4 0.08 W, 2 CHANNEL, AUDIO AMPLIFIER, PDSO20
TPA6120A2DWPR 0.08 W, 2 CHANNEL, AUDIO AMPLIFIER, PDSO20
相关代理商/技术参数
参数描述
TPA6112A2DGQRG4 功能描述:音频放大器 Stereo Diff Input Stereo Headphone 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
TPA6112A2EVM 功能描述:音频 IC 开发工具 TPA6112A2 Eval Mod RoHS:否 制造商:Texas Instruments 产品:Evaluation Kits 类型:Audio Amplifiers 工具用于评估:TAS5614L 工作电源电压:12 V to 38 V
TPA6113A2D 功能描述:音频放大器 40mW Stereo Audio Pwr Amp 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
TPA6113A2DG4 功能描述:音频放大器 40mW Stereo Audio Pwr Amp 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
TPA6113A2DR 功能描述:音频放大器 40mW Stereo Audio Pwr Amp 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