MIC2951-4.8BM Micrel Semiconductor, MIC2951-4.8BM Datasheet - Page 11

• Manufacturer Part Number: MIC2951-4.8BM
• Description: 150mA Low-Dropout Voltage Regulator
• Manufacturer: Micrel Semiconductor

Noise can be reduced fourfold by a bypass capacitor across
R
Pick:
* SEE APPLICATIONS INFORMATION
Typical Applications
*HIGH INPUT LOWERS V
February 1999
MIC2950/2951
ERROR
OUTPUT
ON
*SLEEP
INPUT
SHUTDOWN
INPUT
1
, since it reduces the high frequency gain from 4 to unity.
VOLTAGE
VOLTAGE
OUTPUT
ERROR
INPUT
OFF
C
5V Regulator with 2.5V Sleep Function
47k
BYPASS
5
3
VALID
Figure 1. ERROR Output Timing
NOT
SD
ERROR
GND
4
OUT
4.75V
MIC2951
*
+V IN
+V IN
TO 2.5V
2 R
1.3V
8
V
1
7
5V
FB
OUT
• 200 Hz
1
1
C-MOS
GATE
100pF
2N3906
470 k
VALID
NOT
*
200k
1%
100k
1%
100k
+V OUT
+
3.3 F
3-59
or about 0.01 F. When doing this, the output capacitor must
be increased to 3.3 F to maintain stability. These changes
reduce the output noise from 430 V to 100 V rms for a 100
kHz bandwidth at 5V output. With the bypass capacitor
added, noise no longer scales with output voltage so that
improvements are more dramatic at higher output voltages.
*MINIMUM INPUT-OUTPUT VOLTAGE RANGES FROM 40
ON
NOTE: PINS 2 AND 6 ARE LEFT OPEN
DEPENDING ON LOAD CURRENT.
ERROR
OUTPUT
SHUTDOWN
INPUT
ON
ERROR
OUTPUT
SHUTDOWN
INPUT
Wide Input Voltage Range Current Limiter
OFF
100k
Figure 2. Adjustable Regulator
5
3
OFF
ERROR
SD
5
3
GND
ERROR
SD
MIC2951
GND
4
+V
8
V
MIC2951
IN
4
IN
+V IN
+V IN
V
FB
REF
V
8
7
OUT
FB
V
1.23V
OUT
7
1
*SEE APPLICATIONS
INFORMATION
1
R 100
m
R
V
1.2
V TO 400
1
*V
OUT
2
pF
OUT
V
x (1 +
OUT
30V
m
3.3µF
V,
V IN
= V
R
R
Micrel
1
2
870 23
870 25
REF
)
3