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参数资料
| 型号： | LM4752T/NOPB |
| 厂商： | NATIONAL SEMICONDUCTOR CORP |
| 元件分类： | 音频／视频放大 |
| 英文描述： | 7 W, 2 CHANNEL, AUDIO AMPLIFIER, PZFM7 |
| 封装： | LEAD FREE, PLASTIC, TO-220, 7 PIN |
| 文件页数： | 6/22页 |
| 文件大小： | 521K |
| 代理商： | LM4752T/NOPB |
Power Dissipation vs Output Power
10003951
Power Dissipation vs Output Power
10003952
Application Information
CAPACITOR SELECTION AND FREQUENCY RESPONSE
With the LM4752, as in all single supply amplifiers, AC cou-
pling capacitors are used to isolate the DC voltage present at
the inputs (pins 2,6) and outputs (pins 1,7). As mentioned
earlier in the External Components section these capacitors
create high-pass filters with their corresponding input/output
impedances. The Typical Application Circuit shown in Fig-
ure 1 shows input and output capacitors of 0.1
μF and 1,000
μF respectively. At the input, with an 83 k typical input re-
sistance, the result is a high pass 3 dB point occurring at 19
Hz. There is another high pass filter at 39.8 Hz created with
the output load resistance of 4
. Careful selection of these
components is necessary to ensure that the desired frequen-
cy response is obtained. The Frequency Response curves in
the Typical Performance Characteristics section show how
different output coupling capacitors affect the low frequency
rolloff.
APPLICATION CIRCUIT WITH MUTE
With the addition of a few external components, a simple mute
circuit can be implemented, such as the one shown in Figure
3. This circuit works by externally pulling down the half supply
bias line (pin 5), effectively shutting down the input stage.
When using an external circuit to pull down the bias, care must
be taken to ensure that this line is not pulled down too quickly,
or output “pops” or signal feedthrough may result. If the bias
line is pulled down too quickly, currents induced in the internal
bias resistors will cause a momentary DC voltage to appear
across the inputs of each amplifier's internal differential pair,
resulting in an output DC shift towards V
SUPPLY. An R-C timing
circuit should be used to limit the pull-down time such that
output “pops” and signal feedthroughs will be minimized. The
pull-down timing is a function of a number of factors, including
the external mute circuitry, the voltage used to activate the
mute, the bias capacitor, the half-supply voltage, and internal
resistances used in the half-supply generator. Table 1 shows
a list of recommended values for the external mute circuitry.
TABLE 1. Values for Mute Circuit
V
MUTE
R1
R2
C1
R3
C
B
V
CC
5V
10 k
10 k 4.7 μF 360 100 μF 21V–32V
V
S
20 k
1.2 k 4.7 μF 180 100 μF 15V–32V
V
S
20 k
910 4.7 μF 180 47 μF 22V–32V
OPERATING IN BRIDGE-MODE
Though designed for use as a single-ended amplifier, the
LM4752 can be used to drive a load differentially (bridge-
mode). Due to the low pin count of the package, only the non-
inverting inputs are available. An inverted signal must be
provided to one of the inputs. This can easily be done with the
use of an inexpensive op-amp configured as a standard in-
verting amplifier. An LF353 is a good low-cost choice. Care
must be taken, however, for a bridge-mode amplifier must
theoretically dissipate four times the power of a single-ended
type. The load seen by each amplifier is effectively half that
of the actual load being used, thus an amplifier designed to
drive a 4
load in single-ended mode should drive an 8 load
when operating in bridge-mode.
www.national.com
14
LM4752
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LM4752TS | 功能描述:音频放大器 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 |
| LM4752TS/NOPB | 功能描述:音频放大器 STEREO 11W AUDIO PWR 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 |
| LM4753 | 制造商:NSC 制造商全称:National Semiconductor 功能描述:Dual 10W Audio Power Amplifier w/Mute, Standby and Volume Control |
| LM4753T | 制造商:Rochester Electronics LLC 功能描述:- Bulk |
| LM4755 | 制造商:NSC 制造商全称:National Semiconductor 功能描述:Stereo 11W Audio Power Amplifier with Mute |
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