参数资料
型号: TS4890ID
厂商: STMICROELECTRONICS
元件分类: 音频/视频放大
英文描述: 1 W, 1 CHANNEL, AUDIO AMPLIFIER, PDSO8
封装: SO-8
文件页数: 18/32页
文件大小: 848K
代理商: TS4890ID
TS4890
25/32
s Power dissipation and efficiency
Hypothesis :
Voltage and current in the load are sinusoidal
(Vout and Iout)
Supply voltage is a pure DC source (Vcc)
Regarding the load we have :
and
Then, the average current delivered by the supply
voltage is
The power delivered by the supply voltage is
Psupply = Vcc IccAVG (W)
Then, the power dissipated by the amplifier is
Pdiss = Psupply - Pout (W)
and the maximum value is obtained when
and its value is
Remark : This maximum value is only depending
on power supply voltage and load values.
The efficiency is the ratio between the output
power and the power supply
The maximum theoretical value is reached when
Vpeak = Vcc, so
s Decoupling of the circuit
Two capacitors are needed to bypass properly the
TS4890. A power supply bypass capacitor Cs and
a bias voltage bypass capacitor Cb.
Cs has especially an influence on the THD+N in
high frequency (above 7kHz) and indirectly on the
power supply disturbances.
With 100F, you can expect similar THD+N
performances like shown in the datasheet.
If Cs is lower than 100F, in high frequency
increase THD+N and disturbances on the power
supply rail are less filtered.
To the contrary, if Cs is higher than 100F, those
disturbances on the power supply rail are more
filtered.
Cb has an influence on THD+N in lower frequency,
but its function is critical on the final result of PSRR
with input grounded in lower frequency.
If Cb is lower than 1F, THD+N increase in lower
frequency (see THD+N vs frequency curves) and
the PSRR worsens up
If Cb is higher than 1F, the benefit on THD+N in
lower frequency is small but the benefit on PSRR
is substantial (see PSRR vs. Cb curves).
Note that Cin has a non-negligible effect on PSRR
in lower frequency. Lower is its value, higher is the
PSRR (see fig. 13).
s Pop and Click performance
In order to have the best performances with the
pop and click circuitry, the formula below must be
follow :
With
and
)
V
(
t
sin
V
PEAK
OUT
ω
=
)
A
(
R
V
I
L
OUT
OUT =
)
W
(
R
2
V
P
L
2
PEAK
OUT =
)
A
(
R
V
2
Icc
L
PEAK
AVG
π
=
)
W
(
P
R
Vcc
2
Pdiss
OUT
L
π
=
0
P
Pdiss
OUT
=
)
W
(
R
Vcc
2
max
Pdiss
L
2
π
=
Vcc
4
V
ply
sup
P
PEAK
OUT
π
=
η
%
5
.
78
4
=
π
b
in
τ
τ
)
s
(
C
)
R
(
in
feed
in
×
+
=
τ
)
s
(
C
k
50
b
×
=
τ
相关PDF资料
PDF描述
TS4890IST 1 W, 1 CHANNEL, AUDIO AMPLIFIER, PDSO8
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TS4890IQT 功能描述:音频放大器 1W Mono Audio Power Amplifier 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
TS4890IS 制造商:未知厂家 制造商全称:未知厂家 功能描述:AUDIO AMPLIFIER|SINGLE|BIPOLAR|TSSOP|8PIN|PLASTIC
TS4890IST 功能描述:音频放大器 1W Audio Power 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
TS489IQT 功能描述:音频放大器 100mW Stereo 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