參數(shù)資料
型號(hào)： TPA741DGNRG4
廠商： TEXAS INSTRUMENTS INC
元件分類(lèi)： 音頻／視頻放大
英文描述： 0.7 W, 1 CHANNEL, AUDIO AMPLIFIER, PDSO8
封裝： GREEN, PLASTIC, MSOP-8
文件頁(yè)數(shù)： 9/27頁(yè)
文件大?。?/td> 760K
代理商： TPA741DGNRG4
www.ti.com
USING LOW-ESR CAPACITORS
5-V Versus 3.3-V OPERATION
HEADROOM AND THERMAL CONSIDERATIONS
P
dB +
10Log
P
W
P
ref
+ 10Log
700 mW
1 W
+ –1.5 dB
P
W + 10
PdB 10 x P
ref
TPA741
SLOS316C – JUNE 2000 – REVISED JUNE 2004
Low-ESR capacitors are recommended throughout this applications section. A real (as opposed to ideal)
capacitor can be modeled simply as a resistor in series with an ideal capacitor. The voltage drop 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 behaves like an ideal capacitor.
The TPA741 operates over a supply range of 2.5 V to 5.5 V. This data sheet provides full specifications for 5-V
and 3.3-V operation, as these are considered to be the two most common standard voltages. There are no
special considerations for 3.3-V versus 5-V operation with respect to supply bypassing, gain setting, or stability.
The most important consideration is that of output power. Each amplifier in TPA741 can produce a maximum
voltage swing of VDD - 1 V. This means, for 3.3-V operation, clipping starts to occur when VO(PP) = 2.3 V, as
opposed to VO(PP) = 4 V for 5-V operation. The reduced voltage swing subsequently reduces maximum output
power into an 8-
load before distortion becomes significant.
Operation from 3.3-V supplies, as can be shown from the efficiency formula in Equation 4, consumes
approximately two-thirds the supply power of operation from 5-V supplies for a given output-power level.
Linear power amplifiers dissipate a significant amount of heat in the package under normal operating conditions.
A typical music CD requires 12 dB to 15 dB of dynamic headroom to pass the loudest portions without distortion
as compared with the average power output. From the TPA741 data sheet, one can see that when the TPA741
is operating from a 5-V supply into a 8-
speaker that 700-mW peaks are available. Converting watts to dB:
Subtracting the headroom restriction to obtain the average listening level without distortion yields:
1.5 dB – 15 dB = –16.5 (15-dB headroom)
1.5 dB – 12 dB = –13.5 (12-dB headroom)
1.5 dB – 9 dB = –10.5 (9-dB headroom)
1.5 dB – 6 dB = –7.5 (6-dB headroom)
1.5 dB – 3 dB = –4.5 (3-dB headroom)
Converting dB back into watts:
= 22 mW (15-dB headroom)
= 44 mW (12-dB headroom)
= 88 mW (9-dB headroom)
= 175 mW (6-dB headroom)
= 350 mW (3- dB headroom)
This is valuable information to consider when attempting to estimate the heat dissipation requirements for the
amplifier system. Comparing the absolute worst case, which is 700 mW of continuous power output with 0 dB of
headroom, against 12-dB and 15-dB applications drastically affects maximum ambient temperature ratings for
the system. Using the power dissipation curves for a 5-V, 8-
system, the internal dissipation in the TPA741 and
maximum ambient temperatures is shown in Table 2.
17
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參數(shù)描述
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TPA741DRG4 功能描述:音頻放大器 Mono Diff Input Class-AB RoHS:否 制造商:STMicroelectronics 產(chǎn)品:General Purpose Audio Amplifiers 輸出類(lèi)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
TPA741EVM 功能描述:音頻 IC 開(kāi)發(fā)工具 TPA741 Eval Mod RoHS:否 制造商:Texas Instruments 產(chǎn)品:Evaluation Kits 類(lèi)型:Audio Amplifiers 工具用于評(píng)估:TAS5614L 工作電源電壓:12 V to 38 V
TPA751 制造商:TI 制造商全稱(chēng):Texas Instruments 功能描述:700-mW MONO LOW-VOLTAGE AUDIO POWER AMPLIFIER WITH DIFFERENTIAL INPUTS
TPA751_07 制造商:TI 制造商全稱(chēng):Texas Instruments 功能描述:700-mW MONO LOW-VOLTAGE AUDIO POWER AMPLIFIER WITH DIFFERENTIAL INPUTS
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