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參數(shù)資料
| 型號(hào)： | AIC2951 |
| 廠商： | Analog Integrations Corporation |
| 英文描述： | Low Dropout Linear Regulator |
| 中文描述： | 低壓差線性穩(wěn)壓器 |
| 文件頁(yè)數(shù)： | 8/10頁(yè) |
| 文件大?。?/td> | 153K |
| 代理商： | AIC2951 |
AIC2951/2951D
8
dividers are provided for 3.0V/3.3V/5.0V output ver-
sions. To use the internal voltage divider, connect
the SENSE pin to output and the TAP pin to the FB
pin. When using an external divider the SENSE and
TAP pins are left open, and the divider is installed
from the output to ground, with its center connected
to the FB pin (see Fig. 1). When using an external
voltage divider, resistance can be calculated from
the following formula:
R1
R2)
V
V
(1
I
R1
OUT
REF
FB
=
×
+
+
×
C3
0.01
μ
F
C2
3.3
μ
F
C1
AIC2951
8
7
6
5
4
3
2
1
FB
GND
SENSE
SHDN
TAP
VIN
VOUT
SHUTDOWN
V
OUT
V
IN
R2
R1
+
ERROR
+
Fig. 1 Adjustable Regulator
Where V
REF
is the nominal 1.235V reference voltage
and I
FB
is the feedback pin bias current, nominally -
20nA. The minimum recommended load current of
1
μ
A forces an upper limit of 1.2M
on the value of
R2. Using a 1.2M
resistor for R2, the bias current
will already cause a 2% shift in output voltage. For
better accuracy, choosing R2=100K
reduces this
error to 0.17% at the price of merely increasing the
resistor programming current to 12
μ
A.
Reducing Output Noise
n reference applications it may be advantageous to
reduce the AC noise present at the output. One
method is to reduce the regulator bandwidth by in-
creasing the size of the output capacitor. Another,
noise can be reduced by bypassing the upper re-
sistor in the feedback divider with a small capacitor,
since the capacitor provides a more direct path for
AC feedback. The size of this capacitor can be cal-
culated from the formula:
C
BYPASS
1/(2
π
R1
f
CORNER
)
Where R
1
is the upper resistor of the feedback d-
vider and f
CORNOR
is the frequency above which the
increased AC feedback is to become active. The
reduction of the output noise at high frequency will
be proportional to the ratio of the two resistors in
the feedback divider, R2/(R1+R2). In order to main-
tain regulator stability when using a noise-reducing
bypass capacitor, it will also be necessary to in-
crease the size of the output filter capacitor by the
same ratio
.
n
APPLICAT ION E X AMPLE S
ERROR
C2
R2
1K
R1
*
R3
390
R4
33
Q1
D45H2A
AIC2951
8
7
6
5
4
3
2
1
FB
GND
SENSE
SHDN
TAP
VIN
VOUT
V
IN
5V
6.3V
1000
μ
F
V
OUT
6.3V
1000
μ
Fx5
V
OUT
=1.235(1+R1/1K)
+
C1
+
Load Transient Response
Time (mS)
L
(
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
100
0
-100
5
0
O
(
V
OUT
=3.3V
Fig. 2 Pentium
Processor Power Supply
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| AIC2951-30CN | Low Dropout Linear Regulator |
| AIC2951-30CS | Low Dropout Linear Regulator |
| AIC2951-33CN | Low Dropout Linear Regulator |
| AIC2951-33CS | Low Dropout Linear Regulator |
| AIC2951-50CN | Low Dropout Linear Regulator |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| AIC2951-30CN | 制造商:AIC 制造商全稱(chēng):Analog Intergrations Corporation 功能描述:Low Dropout Linear Regulator |
| AIC2951-30CS | 制造商:AIC 制造商全稱(chēng):Analog Intergrations Corporation 功能描述:Low Dropout Linear Regulator |
| AIC2951-33CN | 制造商:AIC 制造商全稱(chēng):Analog Intergrations Corporation 功能描述:Low Dropout Linear Regulator |
| AIC2951-33CS | 制造商:AIC 制造商全稱(chēng):Analog Intergrations Corporation 功能描述:Low Dropout Linear Regulator |
| AIC2951-50CN | 制造商:AIC 制造商全稱(chēng):Analog Intergrations Corporation 功能描述:Low Dropout Linear Regulator |
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