参数资料
型号: TS4890
厂商: 意法半导体
英文描述: RAIL TO RAIL OUTPUT 1W AUDIO POWER AMPLIFIER WITH STANDBY MODE ACTIVE LOW
中文描述: 轨至轨输出1W的音频功率放大器,具有备用模式有源低
文件页数: 26/32页
文件大小: 833K
代理商: TS4890
TS4890
26/32
I
Power amplifier design examples
Given :
Load impedance : 8
Output power @ 1% THD+N : 0.5W
Input impedance : 10k
min.
Input voltage peak to peak : 1Vpp
Bandwidth frequency : 20Hz to 20kHz (0, -3dB)
THD+N in 20Hz to 20kHz < 0.5% @Pout=0.45W
Ambient temperature max = 50°C
SO8 package
First of all, we must calculate the minimum power
supply voltage to obtain 0.5W into 8
. See curves
in fig. 15, we can read 3.5V. Thus, the power
supply voltage value min. will be 3.5V.
Following the maximum power dissipation
equation :
with 3.5V we have Pdissmax=0.31W.
Refer to power derating curves (fig. 24), with
0.31W the maximum ambient temperature will be
100°C. This last value could be higher if you follow
the example layout shows on the demoboard
(better dissipation).
The gain of the amplifier in flat region will be :
We have Rin > 10k
. Let's take Rin = 10k
, then
Rfeed = 28.25k
. We could use for Rfeed = 30k
in normalized value and the gain will be Gv = 6.
In lower frequency we want 20 Hz (-3dB cut off
frequency). Then
1
C
IN
π
So, we could use for Cin a 1μF capacitor value that
gives 16Hz.
In Higher frequency we want 20kHz (-3dB cut off
frequency). The Gain Bandwidth Product of the
TS4890 is 2MHz typical and doesn't change when
the amplifier delivers power into the load.
The first amplifier has a gain of
and the theoretical value of the -3dB cut of higher
frequency is 2MHz/3 = 660kHz.
We can keep this value or limiting the bandwidth
by adding a capacitor Cfeed, in parallel on Rfeed.
Then
1
C
FEED
π
So, we could use for Cfeed a 220pF capacitor
value that gives 24kHz.
Now, we can choose the value of Cb with the
constraint THD+N in 20Hz to 20kHz < 0.5% @
Pout=0.45W. If you refer to the closest THD+N vs
frequency measurement : fig. 71 (Vcc=3.3V,
Gv=10), with Cb = 1μF, the THD+N vs frequency
is always below 0.4%. As the behaviour is the
same with Vcc = 5V (fig. 67), Vcc = 2.6V (fig. 67).
As the gain for these measurements is higher
(worst case), we can consider with Cb = 1μF, Vcc
= 3.5V and Gv = 6, that the THD+N in 20Hz to
20kHz range with Pout = 0.45W will be lower than
0.4%.
In the following tables, you could find three
another examples with values required for the
demoboard.
Remark :
components with (*) marking are
optional.
Application n°1 : 20Hz to 20kHz bandwidth and
6dB gain BTL power amplifier.
Components :
)
W
(
R
Vcc
2
π
2
max
Pdiss
L
2
=
65
.
V
P
R
2
2
V
V
G
INPP
OUT
L
INPP
OUTPP
V
=
=
=
nF
795
F
Rin
2
CL
=
=
Designator
Part Type
R1
22k / 0.125W
R4
22k / 0.125W
R6
Short Cicuit
R7*
(Vcc-Vf_led)/If_led
R8
10k / 0.125W
C5
470nF
C6
100μF
3
Rin
Rfeed
=
pF
265
F
R
2
CH
FEED
=
=
相关PDF资料
PDF描述
TS4890IQT RAIL TO RAIL OUTPUT 1W AUDIO POWER AMPLIFIER WITH STANDBY MODE ACTIVE LOW
TS4890ID RAIL TO RAIL OUTPUT 1W AUDIO POWER AMPLIFIER WITH STANDBY MODE ACTIVE LOW
TS4890IDT RAIL TO RAIL OUTPUT 1W AUDIO POWER AMPLIFIER WITH STANDBY MODE ACTIVE LOW
TS4900 300mW at 3.3V SUPPLY AUDIO POWER AMPLIFIER WITH STANDBY MODE ACTIVE HIGH
TS4900ID 300mW at 3.3V SUPPLY AUDIO POWER AMPLIFIER WITH STANDBY MODE ACTIVE HIGH
相关代理商/技术参数
参数描述
TS4890ID 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
TS4890IDT 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
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