MIC2950/2951
Micrel
MINIMUM OPERATING VOLTAGE (V)
2.2
2.1
2.0
1.9
1.8
1.7
MIC2951
Minimum Operating Voltage
BIAS CURRENT (nA)
20
10
0
-10
-20
MIC2951
Feedback Bias Current
FEEDBACK CURRENT (µA)
50
0
-50
-100
-150
MIC2951
Feedback Pin Current
PIN 7 DRIVEN BY EXTERNAL
SOURCE (REGULATOR RUN
OPEN LOOP)
T
A
= 125°C
T
A
= 25°C
-200
T
A
= –55°C
-250
-2.0 -1.5 -1.0 -0.5 0
0.5
1.0
1.6
-75 -50 -25 0 25 50 75 100 125 150
TEMPERATURE (°C)
-30
-75 -50 -25 0 25 50 75 100 125 150
TEMPERATURE (°C)
FEEDBACK VOLTAGE (V)
8
COMPARATOR OUTPUT (V)
2.5
SINK CURRENT (mA)
V
OUT
= 5V
6
4
HYSTERESIS
2
0
-2
0
PULLUP RESISTOR TO
SEPARATE 5V SUPPLY
2.0
1.5
1.0
T
A
= 125°C
OUTPUT VOLTAGE
CHANGE
MIC2951
Error Comparator Output
MIC2951
Comparator Sink Current
400
mV
200
mV
0
-50
mV
8V
6V
4V
Line Transient Response
T
A
= 25°C
0.5
0.0
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
OUTPUT LOW VOLTAGE (V)
1
2
3
4
5
6
INPUT
VOLTAGE
T
A
= -55°C
C
L
= 4.7µF
I
L
= 1 mA
V
OUT
= 5V
0
200
400
600
800
INPUT VOLTAGE (V)
TIME (µS)
Load Transient Response
OUTPUT VOLTAGE
LOAD
CHANGE (mV)
CURRENT
Load Transient Response
SHUTDOWN
OUTPUT
PIN VOLTAGE (V) VOLTAGE (V)
MIC2951
Enable Transient
7
6
5
4
3
2
1
0
2
0
-2
C
L
= 1.5
µF
125
100
75
50
25
0
-25
-50
100
mA
100
µA
0
2
4
LOAD
CURRENT
C
L
= 4.7
µF
V
OUT
= 5V
80
60
40
20
0
-20
-40
-60
100
mA
100
µA
0
4
8
OUTPUT VOLTAGE
CHANGE (mV)
C
L
= 15
µF
V
OUT
= 5V
I
L
= 10 mA
V
IN
= 8V
C
L
= 10
µF
V
OUT
= 5V
6
8
10
12
16
20
-100 0 100 200 300 400 500 600 700
TIME (µS)
TIME (mS)
TIME (mS)
Output Impedance
OUTPUT IMPEDANCE (OHMS)
Ripple Rejection
90
RIPPLE REJECTION (dB)
Ripple Rejection
90
RIPPLE REJECTION (dB)
10
5
2
1
0.5
0.2
0.1
0.05
0.02
0.01
I
0
= 100
µA
I
0
= 1 mA
I
0
= 100 mA
V
OUT
= 5V
C
L
= 4.7
µF
80
70
60
50
40
30
20
C
L
= 1.5
µF
V
IN
= 6V
V
OUT
= 5V
10
1
10
2
10
3
I
L
= 100
µA
I
L
= 0
80
70 I = 1 mA
L
60
50
40
30
20
10
1
C
L
= 1.5
µF
V
IN
= 6V
V
OUT
= 5V
I
L
= 10 mA
10
2
10
3
10
4
10
5
10
6
FREQUENCY (Hz)
10
100
1K
10K 100K 1M
10
4
10
10
6
FREQUENCY (Hz)
FREQUENCY (Hz)
3-56
February 1999
MICREL [ MICREL SEMICONDUCTOR ]
