LP2951
© 1998 SEMTECH CORP.
150mA ADJUSTABLE
VOLTAGE REGULATOR
March 17, 1998
652 MITCHELL ROAD NEWBURY PARK CA 91320
1
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
TEL:805-498-2111 FAX:805-498-3804 WEB:http://www.semtech.com
PIN CONFIGURATION
BLOCK DIAGRAM
ABSOLUTE MAXIMUM RATINGS
Parameter Symbol Maximum Units
Supply Voltage VIN -0.3 to 30 V
Shutdown Input
Voltage -0.3 to 30 V
Error Comp. Output
Voltage -0.3 to 30 V
Power Dissipation PDInternally
Limited W
Thermal Resistance
Junction to Ambient θJA 175 °C/W
Operating Junction
Temperature Range TJ-40 to 125 °C
Storage
Temperature Range TSTG -65 to 150 °C
Lead Temperature
(Soldering) 5 Sec TLEAD 260 °C
APPLICATIONS
•=Microcontroller supplies
•=Linear regulators
•=Adjustable Supplies
•=Switching power supplies - post-regulation
•=Portable modems
•=Battery powered systems
•=Cellular telephones
•=Voltage references
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.
ORDERING INFORMATION
DEVICE(1)(2) OUTPUT PACKAGE
LP2951CM-X.X ADJ SO-8
LP2951
© 1998 SEMTECH CORP.
150mA ADJUSTABLE
VOLTAGE REGULATOR
March 17, 1998
652 MITCHELL ROAD NEWBURY PARK CA 91320
2
NOTE:
(1) Temperature coefficient is defined as the worst case voltage change divided by total temperature range.
ELECTRICAL CHARACTERISTICS
Unless specified, limits are over operating temperature range (TJ = TA), VIN = VOUT(NOM) + 1V, IL=100µA, CL=1µF
Parameter Symbol Conditions Min Typ Max Units
Output Voltage
LP2951CM VOUT TJ = 25°C, IL = 100µA 4.950 5.000 5.050 V
LP2951CM-3.3 3.267 3.300 3.333
Temp Coefficient(1) TC0°C ≤ TJ ≤=70°C 20 120 ppm/°C
Line Regulation REG(LINE) (VO(NOM) + 1V) ≤ VIN=≤=30V 0.1 0.5 %
Load Regulation REG(LOAD) 100µA ≤ IL=≤=100mA 0.1 0.4 %
Dropout Voltage VDIL===100µA 80 150 mV
IL===100mA 380 600
Ground Current IGND IL===100µA 120 160 µA
IL===100mA 814 mA
Dropout Ground Current IGND(D) VIN = (VO(NOM) - 0.5V), IL===100µA 110 250 µA
Current Limit ICL VOUT = 0 200 250 mA
Reference Voltage VREF VREF ≤ VOUT ≤ (VIN - 1V), TJ ==25°C,
100µA ≤ IL=≤=100mA 1.210 1.235 1.260 V
Feedback Bias Current IFB 20 60 nA
Error Comparator
Output High Leakage
Current VOH = 30V 2 µA
Output Low Voltage VIN = (VO(NOM) - 0.5V), IOL = 400µA 150 400 mV
Threshold Voltage Upper 25 60 mV
Lower 75 140
Hysteresis 15 mV
Shutdown Input
Input Logic Voltage VSD Low 0.6 V
High 2.0 V
Input Current ISD VSHUTDOWN = 2.4V 100 µA
VSHUTDOWN = 30V 750
Regulator Shutdown
Output Current IO(SD) VSHUTDOWN ≥ 2V, VIN ≤ 30V,
VOUT = 0, Feedback pin to Tap 20 µA
LP2951
© 1998 SEMTECH CORP.
150mA ADJUSTABLE
VOLTAGE REGULATOR
March 17, 1998
652 MITCHELL ROAD NEWBURY PARK CA 91320
3
OUTLINE DRAWING SO -8
LAND PATTERN SO-8
