參數(shù)資料
型號: TS4994EIKJT
廠商: STMICROELECTRONICS
元件分類: 音頻/視頻放大
英文描述: 1.2 W, 1 CHANNEL, AUDIO AMPLIFIER, PBGA9
封裝: ROHS COMPLIANT, FCP-9
文件頁數(shù): 16/35頁
文件大?。?/td> 694K
代理商: TS4994EIKJT
TS4994FC
Application information
23/35
4
Application information
4.1
Differential configuration principle
The TS4994 is a monolithic full-differential input/output power amplifier. The TS4994 also
includes a common mode feedback loop that controls the output bias value to average it at
VCC/2 for any DC common mode input voltage. This allows the device to always have a
maximum output voltage swing, and by consequence, maximize the output power.
Moreover, as the load is connected differentially, compared to a single-ended topology, the
output is four times higher for the same power supply voltage.
The advantages of a full-differential amplifier are:
Very high PSRR (power supply rejection ratio).
High common mode noise rejection.
Virtually zero pop without additional circuitry, giving a faster start-up time compared
with conventional single-ended input amplifiers.
Easier interfacing with differential output audio DAC.
No input coupling capacitors required due to common mode feedback loop.
In theory, the filtering of the internal bias by an external bypass capacitor is not
necessary. But, to reach maximum performance in all tolerance situations, it is better to
keep this option.
The main disadvantage is:
As the differential function is directly linked to the mismatch between external resistors,
paying particular attention to this mismatch is mandatory in order to get the best
performance from the amplifier.
4.2
Gain in typical application schematic
A typical differential application is shown in Figure 1 on page 3.
In the flat region of the frequency-response curve (no Cin effect), the differential gain is
expressed by the relation:
where Rin = Rin1 = Rin2 and Rfeed = Rfeed1 = Rfeed2.
Note:
For the rest of this section, Avdiff will be called AV to simplify the expression.
4.3
Common mode feedback loop limitations
As explained previously, the common mode feedback loop allows the output DC bias voltage
to be averaged at VCC/2 for any DC common mode bias input voltage.
However, due to VICM limitation of the input stage (see Table 3 on page 5), the common
mode feedback loop can play its role only within a defined range. This range depends upon
A
V
diff
V
O+
V
O
Diff
input+
Diff
input-
------------------------------------------------------
R
feed
R
in
--------------
==
相關(guān)PDF資料
PDF描述
TS4994IQT 1 W, 1 CHANNEL, AUDIO AMPLIFIER, DSO8
TS4994IST 1 W, 1 CHANNEL, AUDIO AMPLIFIER, PDSO8
TS4995EIJT 1.2 W, 1 CHANNEL, AUDIO AMPLIFIER, PBGA9
TS4998IQT 1 W, 2 CHANNEL, AUDIO AMPLIFIER, QCC16
TS555CPT PULSE; RECTANGULAR, 2 MHz, TIMER, PDSO8
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
TS4994FC 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:1.2 W differential input/output audio power amplifier with selectable standby
TS4994IJT 功能描述:音頻放大器 STANDARD LINEAR RoHS:否 制造商:STMicroelectronics 產(chǎn)品:General Purpose Audio Amplifiers 輸出類型:Digital 輸出功率: THD + 噪聲: 工作電源電壓:3.3 V 電源電流: 最大功率耗散: 最大工作溫度: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:TQFP-64 封裝:Reel
TS4994IQT 功能描述:音頻放大器 1W diff input/output audio Pwr amplifier RoHS:否 制造商:STMicroelectronics 產(chǎn)品:General Purpose Audio Amplifiers 輸出類型:Digital 輸出功率: THD + 噪聲: 工作電源電壓:3.3 V 電源電流: 最大功率耗散: 最大工作溫度: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:TQFP-64 封裝:Reel
TS4994IST 功能描述:音頻放大器 1W Audio Power Amp RoHS:否 制造商:STMicroelectronics 產(chǎn)品:General Purpose Audio Amplifiers 輸出類型:Digital 輸出功率: THD + 噪聲: 工作電源電壓:3.3 V 電源電流: 最大功率耗散: 最大工作溫度: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:TQFP-64 封裝:Reel
TS4995 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:1.2 W fully differential audio power amplifier with selectable standby and 6 dB fixed gain