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參數(shù)資料
| 型號： | KB4863M |
| 廠商： | Electronic Theatre Controls, Inc. |
| 元件分類： | 運動控制電子 |
| 英文描述： | Dual 2.2W Audio Amplifier Plus Stereo Headphone Function |
| 中文描述： | 雙2.2W的立體聲音頻放大器加上耳機功能 |
| 文件頁數(shù)： | 15/19頁 |
| 文件大?。?/td> | 610K |
| 代理商： | KB4863M |
Application Information
(Continued)
sents a tradeoff: as the size of C
increases, the turn-on time
increases. There is a linear relationship between the size of
C
and the turn-on time. Here are some typical turn-on times
for various values of C
B
:
C
B
0.01μF
0.1μF
0.22μF
0.47μF
1.0μF
T
ON
20 ms
200 ms
440 ms
940 ms
2 Sec
In order eliminate ’clicks and pops’, all capacitors must be
discharged before turn-on. Rapidly switching V
may not
allow the capacitors to fully discharge, which may cause
’clicks and pops’. In a single-ended configuration, the output
is coupled to the load by C
. This capacitor usually has a
high value. C
discharges through internal 20k
resistors.
Depending on the size of C
, the discharge time constant
can be relatively large. To reduce transients in single-ended
mode, an external 1k
- 5k
resistor can be placed in
parallel with the internal 20k
resistor. The tradeoff for using
this resistor is increased quiescent current.
NO LOAD STABILITY
The KB4863 may exhibit low level oscillation when the load
resistance is greater than 10k
. This oscillation only occurs
as the output signal swings near the supply voltages. Pre-
vent this oscillation by connecting a 5k
between the output
pins and ground.
AUDIO POWER AMPLIFIER DESIGN
Audio Amplifier Design: Driving 1W into an 8
Load
The following are the desired operational parameters:
Power Output:
Load Impedance:
Input Level:
Input Impedance:
Bandwidth:
1Wrms
8
1Vrms
20k
100Hz20 kHz
±
0.25 dB
The design begins by specifying the minimum supply voltage
necessary to obtain the specified output power. One way to
find the minimum supply voltage is to use the Output Power
vs Supply Voltage curve in the
Typical Performance Char-
acteristics
section. Another way, using Equation (4), is to
calculate the peak output voltage necessary to achieve the
desired output power for a given load impedance. To ac-
count for the amplifier’s dropout voltage, two additional volt-
ages, based on the Dropout Voltage vs Supply Voltage in the
Typical Performance Characteristics
curves, must be
added to the result obtained by Equation (8). The result in
Equation (9).
(8)
(9)
V
DD
≥
(V
OUTPEAK
+ (V
OD
TOP
+ V
OD
BOT
))
The Output Power vs Supply Voltage graph for an 8
load
indicates a minimum supply voltage of 4.6V. This is easily
met by the commonly used 5V supply voltage. The additional
voltage creates the benefit of headroom, allowing the
KB4863 to produce peak output power in excess of 1W
without clipping or other audible distortion. The choice of
supply voltage must also not create a situation that violates
maximum power dissipation as explained above in the
Power Dissipation
section.
After satisfying the KB4863’s power dissipation require-
ments, the minimum differential gain is found using Equation
(10).
(10)
Thus, a minimum gain of 2.83 allows the KB4863’s to reach
full output swing and maintain low noise and THD+N perfor-
mance. For this example, let A
VD
= 3.
The amplifier’s overall gain is set using the input (R
) and
feedback (R
) resistors. With the desired input impedance
set at 20k
, the feedback resistor is found using Equation
(11).
R
f
/R
i
= A
VD
/2
The value of R
f
is 30k
.
The last step in this design example is setting the amplifier’s
3dB frequency bandwidth. To achieve the desired
±
0.25dB
pass band magnitude variation limit, the low frequency re-
sponse must extend to at least onefifth the lower bandwidth
limit and the high frequency response must extend to at least
five times the upper bandwidth limit. The gain variation for
both response limits is 0.17dB, well within the
±
0.25dB
desired limit. The results are an
f
L
= 100Hz/5 = 20Hz
and an
F
H
= 20kHzx5 = 100kHz
As mentioned in the
External Components
section, R
i
and C
create a highpass filter that sets the amplifier’s lower
bandpass frequency limit. Find the coupling capacitor’s
value using Equation (12).
(11)
(12)
(13)
the result is
1/(2
π
*
20k
*
20Hz) = 0.398μF
Use a 0.39μF capacitor, the closest standard value.
The product of the desired high frequency cutoff (100kHz in
this example) and the differential gain, A
VD
, determines the
upper passband response limit. With A
VD
= 3 and f
H
=
100kHz, the closed-loop gain bandwidth product (GBWP) is
300kHz. This is less than the KB4863’s 3.5MHz GBWP. With
this margin, the amplifier can be used in designs that require
more differential gain while avoiding performance-lrestricting
bandwidth limitations.
(14)
RECOMMENDED PRINTED CIRCUIT BOARD LAYOUT
Figures 3 through 6 show the recommended two-layer PC
board layout that is optimized for the 20-pin MTE-packaged
KB4863 and associated external components. Figures 7
through 11 show the recommended four-layer PC board
layout that is optimized for the 24-pin LQ-packaged KB4863
and associated external components. These circuits are de-
signed for use with an external 5V supply and 4
speakers.
These circuit boards are easy to use.Apply 5V and ground to
the board’s V
and GND pads, respectively. Connect 4
speakers between the board’s -OUTA and +OUTA and
OUTB and +OUTB pads.
KingborTechnologyCo.,Ltd
TEL:(86)0755-83095458 FAX:(86)0755-88364052
KB4863
15/19
Rev: 1.1
2005-12-05
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| KB4863MT | Dual 2.2W Audio Amplifier Plus Stereo Headphone Function |
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相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| KB4863MT | 制造商:KINGBOR 制造商全稱:KINGBOR 功能描述:Dual 2.2W Audio Amplifier Plus Stereo Headphone Function |
| KB4863MTE | 制造商:KINGBOR 制造商全稱:KINGBOR 功能描述:Dual 2.2W Audio Amplifier Plus Stereo Headphone Function |
| KB4863N | 制造商:KINGBOR 制造商全稱:KINGBOR 功能描述:Dual 2.2W Audio Amplifier Plus Stereo Headphone Function |
| KB491D | 制造商:KEXIN 制造商全稱:Guangdong Kexin Industrial Co.,Ltd 功能描述:Schottky Barrier Diodes |
| KB4A101K-L018B-ROHS | 制造商:Hitano Enterprise Corp 功能描述:Bulk |
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