参数资料
型号: TPA6205A1DRBRG4
厂商: TEXAS INSTRUMENTS INC
元件分类: 音频/视频放大
英文描述: 1.25 W, 1 CHANNEL, AUDIO AMPLIFIER, PDSO8
封装: 3 X 3 MM, GREEN, PLASTIC, SON-8
文件页数: 4/28页
文件大小: 912K
代理商: TPA6205A1DRBRG4
Summing a Differential Input Signal and a
Decoupling Capacitor (CS)
Gain 1 +
V
O
V
I1
+ *
R
F
R
I1
V
(6)
Gain 2 +
V
O
V
I2
+ *
R
F
R
I2
V
(7)
USING LOW-ESR CAPACITORS
SUMMING INPUT SIGNALS WITH THE
DIFFERENTIAL OUTPUT VERSUS
Summing Two Differential Input Signals
Gain 1 +
V
O
V
I1
+ *
R
F
R
I1
V
(4)
Gain 2 +
V
O
V
I2
+ *
R
F
R
I2
V
(5)
SLOS490B – JULY 2006 – REVISED JUNE 2008 ..............................................................................................................................................................
www.ti.com
(RI, CI) and the feedback resistor (RF) to the load.
Single-Ended Input Signal
This leakage current creates a dc offset voltage at the
input to the amplifier that reduces useful headroom,
Figure 31 shows how to sum a differential input signal
especially in high gain applications. For this reason, a
and a single-ended input signal. Ground noise can
ceramic capacitor is the best choice. When polarized
couple in through IN+ with this method. It is better to
capacitors are used, the positive side of the capacitor
use differential inputs. To assure that each input is
should face the amplifier input in most applications,
balanced, the single-ended input must be driven by a
as the dc level there is held at VDD/2, which is likely
low-impedance source even if the input is not in use.
higher than the source dc level. It is important to
Both input nodes must see the same impedance for
confirm the capacitor polarity in the application.
optimum performance, thus the use of RP and CP.
The TPA6205A1 is a high-performance CMOS audio
amplifier
that
requires
adequate
power
supply
decoupling to ensure the output total harmonic
distortion (THD) is as low as possible. Power supply
decoupling also prevents oscillations for long lead
Where
lengths between the amplifier and the speaker. For
CP = CI1 // CI2
higher frequency transients, spikes, or digital hash on
RP = RI1 // RI2
the line, a good low equivalent-series- resistance
(ESR) ceramic capacitor, typically 0.1
F to 1 F,
placed as close as possible to the device VDD lead
works best. For filtering lower frequency noise
Low-ESR capacitors are recommended throughout
signals, a 10-
F or greater capacitor placed near the
this applications section. A real (as opposed to ideal)
audio power amplifier also helps, but is not required
capacitor can be modeled simply as a resistor in
in most applications because of the high PSRR of this
series with an ideal capacitor. The voltage drop
device.
across this resistor minimizes the beneficial effects of
the capacitor in the circuit. The lower the equivalent
value of this resistance the more the real capacitor
TPA6205A1
behaves like an ideal capacitor.
Most wireless phones or PDAs need to sum signals
at the audio power amplifier or just have two signal
sources that need separate gain. The TPA6205A1
SINGLE-ENDED OUTPUT
makes it easy to sum signals or use separate signal
Figure 32 shows a Class-AB audio power amplifier
sources with different gains. Many phones now use
(APA)
in
a
fully
differential
configuration.
The
the same speaker for the earpiece and ringer, where
TPA6205A1 amplifier has differential outputs driving
the wireless phone would require a much lower gain
both ends of the load. There are several potential
for the phone earpiece than for the ringer. PDAs and
benefits to this differential drive configuration, but
phones
that
have
stereo
headphones
require
initially consider power to the load. The differential
summing of the right and left channels to output the
drive to the speaker means that as one side is
stereo signal to the mono speaker.
slewing up, the other side is slewing down, and vice
versa. This in effect doubles the voltage swing on the
load as compared to a ground referenced load.
Two
extra
resistors
are
needed
for
summing
Plugging 2 × VO(PP) into the power equation, where
differential signals (a total of 10 components). The
voltage is squared, yields 4× the output power from
gain for each input source can be set independently
the same supply rail and load impedance (see
12
Copyright 2006–2008, Texas Instruments Incorporated
Product Folder Link(s): TPA6205A1
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TPA6205A1DRBT 功能描述:音频放大器 1.25-W Mono Fully Diff Class-AB Aud 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
TPA6205A1DRBTG4 功能描述:音频放大器 1.25W Mono Fully Diff ClassAB Aud 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
TPA6205A1EVM 功能描述:音频 IC 开发工具 HEADPHONE DRIVER 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
TPA6205A1ZQVR 功能描述:音频放大器 1.25W Mono Fully Diff ClassAB Aud 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
TPA6205A1ZQVRG1 功能描述:音频放大器 1.25W Mon,Fully Diff Class-AB Audio 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