參數(shù)資料
型號: LM4860M
廠商: NATIONAL SEMICONDUCTOR CORP
元件分類: 音頻/視頻放大
英文描述: Series 1W Audio Power Amplifier with Shutdown Mode
中文描述: 1.15 W, 1 CHANNEL, AUDIO AMPLIFIER, PDSO16
封裝: SOIC-16
文件頁數(shù): 7/9頁
文件大?。?/td> 278K
代理商: LM4860M
Application Information
(Continued)
ground resulting from the music coming from the headphone
amplifier. The output coupling cap protects the headphones
by blocking the amplifier’s half-supply DC voltage. The ca-
pacitor also protects the headphone amplifier from the low
voltage set up by resistors R1 and R2 when there aren’t any
headphones plugged into the system. The tricky point to this
setup is that the AC output voltage of the headphone ampli-
fier cannot exceed the 2.0V HP-IN1 voltage threshold when
there aren’t any headphones plugged into the system, as-
suming that R1 and R2 are 100k and 1k, respectively. The
LM4860 may not be fully shutdown when this level is ex-
ceeded momentarily, due to the discharging time constant of
the bias-pin voltage. This time constant is established by the
two 50k resistors (in parallel) with the series bypass capaci-
tor value.
When a set of headphones are plugged into the system, the
contact pin of the headphone jack is disconnected from the
signal pin, interrupting the voltage divider set up by resistors
R1 and R2. Resistor R1 then pulls up the HP-IN1 pin, en-
abling the headphone function and disabling the LM4860
amplifier. The headphone amplifier then drives the head-
phones, whose impedance is in parallel with resistor R2.
Since the typical impedance of headphones are 32
, resis-
tor R2 has negligible effect on the output drive capability.
Also shown in Figure 5 are the electrical connections for the
headphone jack and plug. A 3-wire plug consists of a Tip,
Ring, and Sleave, where the Tip and Ring are signal carrying
conductors and the Sleave is the common ground return.
One control pin contact for each headphone jack is sufficient
to indicate to control inputs that the user has inserted a plug
into a jack and that another mode of operation is desired.
For a system implementation where the headphone amplifier
is designed using a split supply, the output coupling cap, C
C
and resistor R2 of Figure 5 can be eliminated. The function-
ality described earlier remains the same, however.
In addition, the HP-SENSE pin, although it may be con-
nected to the SHUTDOWN pin as shown in Figure 4 may
still be used as a control flag. It is capable of driving the input
to another logic gate or approximately 2 mA without serious
loading.
DS011988-7
FIGURE 4. HP-SENSE Pin to
SHUTDOWN Pin Connection
DS011988-8
FIGURE 5. Typical Headphone Control Input Circuitry
www.national.com
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
LM4860M 制造商:Texas Instruments 功能描述:IC AMP AUDIO 1W SMD 4860 SOIC16
LM4860M/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: 安裝風格:SMD/SMT 封裝 / 箱體:TQFP-64 封裝:Reel
LM4860M_NOPB 制造商:TI 制造商全稱:Texas Instruments 功能描述:Series 1W Audio Power Amplifier with Shutdown Mode
LM4860M-ND 制造商:National Semiconductor Corporation 功能描述: 制造商:Texas Instruments 功能描述:
LM4860MX 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: 安裝風格:SMD/SMT 封裝 / 箱體:TQFP-64 封裝:Reel