150mA ADJUSTABLE
VOLTAGE REGULATOR
March 17, 1998
LP2951
TEL:805-498-2111 FAX:805-498-3804 WEB:http://www.semtech.com
DESCRIPTION
The LP2951 series of low power voltage regulators
have low quiescent current and low dropout voltage.
The quiescent current increases minimally during
dropout conditions thereby extending battery life.
Available in the 8 lead SOIC package, the LP2951 se-
ries includes features such as shutdown and low out-
put voltage detect (typically due to low battery condi-
tions). This function may also be used as a power on
reset function when triggered by CMOS or TTL inputs.
The circuit can be used as a fixed voltage 5 volt (3.3
volt for LP2951CM-3.3) regulator or adjusted between
1.24 volts and 29 volts using external resistor pairs.
FEATURES
•=
Guaranteed 150mA current
•=
Adjustable output voltage - 1.24V to 29V
•=
Accurate 5V or 3.3V output @ 100mA
•=
Low dropout voltage - 350-400mV @ 100mA
•=
Regulator or reference functions
•=
Direct replacement for LP2951C, MIC2951-03,
AS2951C
BLOCK DIAGRAM
APPLICATIONS
•=
Microcontroller supplies
•=
Linear regulators
•=
Adjustable Supplies
•=
Switching power supplies - post-regulation
•=
Portable modems
•=
Battery powered systems
•=
Cellular telephones
•=
Voltage references
ORDERING INFORMATION
DEVICE
(1)(2)
OUTPUT
ADJ
PACKAGE
SO-8
LP2951CM-X.X
Notes:
(1) Where -X.X denotes voltage options. Available
voltages are: 3.3V (-3.3) and 5V (leave blank).
(2) Add suffix ‘TR’ for tape and reel.
ABSOLUTE MAXIMUM RATINGS
Parameter
Symbol
V
IN
Maximum
-0.3 to 30
-0.3 to 30
-0.3 to 30
P
D
θ
JA
T
J
T
STG
T
LEAD
Internally
Limited
175
-40 to 125
-65 to 150
260
Units
V
V
V
W
°C/W
°C
°C
°C
PIN CONFIGURATION
Supply Voltage
Shutdown Input
Voltage
Error Comp. Output
Voltage
Power Dissipation
Thermal Resistance
Junction to Ambient
Operating Junction
Temperature Range
Storage
Temperature Range
Lead Temperature
(Soldering) 5 Sec
1
© 1998 SEMTECH CORP.
652 MITCHELL ROAD NEWBURY PARK CA 91320
150mA ADJUSTABLE
VOLTAGE REGULATOR
March 17, 1998
LP2951
ELECTRICAL CHARACTERISTICS
Unless specified, limits are over operating temperature range (T
J
= T
A
), V
IN
= V
OUT(NOM)
+ 1V, I
L
=100µA, C
L
=1µF
Parameter
Output Voltage
LP2951CM
LP2951CM-3.3
Temp Coefficient
(1)
Line Regulation
Load Regulation
Dropout Voltage
T
C
REG
(LINE)
REG
(LOAD)
V
D
0°C
≤
T
J
≤=70°C
(V
O(NOM)
+ 1V)
≤
V
IN=
≤=30V
100µA
≤
I
L=
≤=100mA
I
L=
==100µA
I
L=
==100mA
Ground Current
I
GND
I
L=
==100µA
I
L=
==100mA
Dropout Ground Current
Current Limit
Reference Voltage
Feedback Bias Current
Error Comparator
Output High Leakage
Current
Output Low Voltage
Threshold Voltage
V
OH
= 30V
V
IN
= (V
O(NOM)
- 0.5V), I
OL
= 400µA
Upper
Lower
Hysteresis
Shutdown Input
Input Logic Voltage
V
SD
I
SD
I
O(SD)
Low
High
Input Current
V
SHUTDOWN
= 2.4V
V
SHUTDOWN
= 30V
Regulator Shutdown
Output Current
V
SHUTDOWN
≥
2V, V
IN
≤
30V,
V
OUT
= 0, Feedback pin to Tap
2.0
100
750
20
µA
0.6
V
V
µA
25
150
60
75
15
140
mV
2
400
µA
mV
mV
I
GND(D)
I
CL
V
REF
I
FB
V
IN
= (V
O(NOM)
- 0.5V), I
L=
==100µA
V
OUT
= 0
V
REF
≤
V
OUT
≤
(V
IN
- 1V), T
J
==25°C,
100µA
≤
I
L=
≤=100mA
1.210
Symbol
V
OUT
Conditions
T
J
= 25°C, I
L
= 100µA
Min
4.950
3.267
Typ
5.000
3.300
20
0.1
0.1
80
380
120
8
110
200
1.235
20
Max
5.050
3.333
120
0.5
0.4
150
600
160
14
250
250
1.260
60
µA
mA
µA
mA
V
nA
ppm/°C
%
%
mV
Units
V
NOTE:
(1) Temperature coefficient is defined as the worst case voltage change divided by total temperature range.
2
© 1998 SEMTECH CORP.
652 MITCHELL ROAD NEWBURY PARK CA 91320
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