- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄358867 > LM4875M (NATIONAL SEMICONDUCTOR CORP) 750 mW Audio Power Amplifier with DC Volume Control and Headphone Switch PDF資料下載
參數(shù)資料
| 型號： | LM4875M |
| 廠商： | NATIONAL SEMICONDUCTOR CORP |
| 元件分類： | 音頻控制 |
| 英文描述： | 750 mW Audio Power Amplifier with DC Volume Control and Headphone Switch |
| 中文描述： | 1 CHANNEL(S), VOLUME CONTROL CIRCUIT, PDSO8 |
| 封裝： | SOIC-8 |
| 文件頁數(shù)： | 7/13頁 |
| 文件大?。?/td> | 673K |
| 代理商： | LM4875M |
Typical Performance Characteristics
(Continued)
Output Power vs Supply Voltage
Output Power vs Supply Voltage
10104231
10104232
Supply Current vs Supply Voltage
10104233
Application Information
BRIDGE CONFIGURATION EXPLANATION
As shown in
Figure 1
, the LM4875 consists of two opera-
tional amplifiers internally. An external DC voltage sets the
closed-loop gain of the first amplifier, whereas two internal
20k
resistors set the second amplifier’s gain at -1. The
LM4875 can be used to drive a speaker connected between
the two amplifier outputs or a monaural headphone con-
nected between V
O
1 and GND.
Figure 1
shows that the output of Amp1 serves as the input
to Amp2. This results in both amplifiers producing signals
that are identical in magnitude, but 180 out of phase.
Taking advantage of this phase difference, a load placed
between V
1 and V
2 is driven differentially (commonly
referred to as “bridge mode“ ). This mode is different from
single-ended driven loads that are connected between a
single amplifier’s output and ground.
Bridge mode has a distinct advantage over the single-ended
configuration: its differential drive to the load doubles the
output swing for a specified supply voltage. This results in
four times the output power when compared to a single-
ended amplifier under the same conditions. This increase in
attainable output assumes that the amplifier is not current
limited or the output signal is not clipped. To ensure mini-
mum output signal clipping when choosing an amplifier’s
closed-loop gain, refer to the
Audio Power Amplifier De-
sign
section.
Another advantage of the differential bridge output is no net
DC voltage across load. This results from biasing V
O
1 and
V
2 at half-supply. This eliminates the coupling capacitor
that single supply, single-ended amplifiers require. Eliminat-
ing an output coupling capacitor in a single-ended configu-
ration forces a single supply amplifier’s half-supply bias volt-
age across the load. The current flow created by the half-
supply bias voltage increases internal IC power dissipation
and may permanently damage loads such as speakers.
POWER DISSIPATION
Power dissipation is a major concern when designing a
successful bridged or single-ended amplifier. Equation (1)
states the maximum power dissipation point for a single-
ended amplifier operating at a given supply voltage and
driving a specified output load.
P
DMAX
= (V
DD
)
2
/(2
π
2
R
L
)
However, a direct consequence of the increased power de-
livered to the load by a bridge amplifier is an increase in
internal power dissipation point for a bridge amplifier oper-
ating at the same given conditions.
P
DMAX
= 4*(V
DD
)
2
/(2
π
2
R
L
)
The LM4875 has two operational amplifiers in one package
and the maximum internal power dissipation is 4 times that
Single-Ended
(1)
Bridge Mode
(2)
L
www.national.com
7
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| LM4875MM | 750 mW Audio Power Amplifier with DC Volume Control and Headphone Switch |
| LM4877IBP | Pressure Transducer, Series 19 mm, Compensated, Pressure Range: 0 psi to 3 psi, Gage, 1/4 BSPP, 10 Vdc excitation |
| LM4877IBPX | Pressure Transducer, Series 19 mm, Compensated, Pressure Range: 0 psi to 5 psi, Gage, Cell with body o-ring, 10 Vdc excitation |
| LM4877 | 1 Watt Audio Power Amplifier in micro SMD package with Shutdown Logic Low |
| LM4880 | Dual 250 mW Audio Power Amplifier with Shutdown Mode |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LM4875M/NOPB | 功能描述:音頻放大器 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 |
| LM4875MM | 功能描述:音頻放大器 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 |
| LM4875MM/NOPB | 功能描述:音頻放大器 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 |
| LM4875MX | 功能描述:音頻放大器 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 |
| LM4875MX/NOPB | 功能描述:音頻放大器 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 |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。