LM2937ES-3.3/NOPB National Semiconductor, LM2937ES-3.3/NOPB Datasheet



Manufacturer Part Number
National Semiconductor

Specifications of LM2937ES-3.3/NOPB

Regulator Topology
Positive Fixed
Voltage - Output
Voltage - Input
Up to 26V
Voltage - Dropout (typical)
0.11V @ 50mA
Number Of Regulators
Current - Output
Operating Temperature
-40°C ~ 125°C
Mounting Type
Surface Mount
Package / Case
TO-263-3, D²Pak (3 leads + Tab), TO-263AA
Number Of Outputs
Input Voltage Max
26 V
Output Voltage
3.3 V
Output Type
Output Current
0.5 A
Line Regulation
9.9 mV
Load Regulation
3.3 mV
Voltage Regulation Accuracy
+/- 5 %
Maximum Operating Temperature
+ 125 C
Mounting Style
Minimum Operating Temperature
- 40 C
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Current - Limit (min)
Lead Free Status / Rohs Status
Other names

Available stocks

Part Number
Part Number:
10 781
Part Number:
© 2005 National Semiconductor Corporation
LM2937-2.5, LM2937-3.3
400mA and 500mA Voltage Regulators
General Description
The LM2937-2.5 and LM2937-3.3 are positive voltage regu-
lators capable of supplying up to 500 mA of load current.
Both regulators are ideal for converting a common 5V logic
supply, or higher input supply voltage, to the lower 2.5V and
3.3V supplies to power VLSI ASIC’s and microcontrollers.
Special circuitry has been incorporated to minimize the qui-
escent current to typically only 10 mA with a full 500 mA load
current when the input to output voltage differential is greater
than 5V.
The LM2937 requires an output bypass capacitor for stabil-
ity. As with most regulators utilizing a PNP pass transistor,
the ESR of this capacitor remains a critical design param-
eter, but the LM2937-2.5 and LM2937-3.3 include special
compensation circuitry that relaxes ESR requirements. The
LM2937 is stable for all ESR ratings less than 5Ω. This
allows the use of low ESR chip capacitors.
The regulators are also suited for automotive applications,
with built in protection from reverse battery connections,
Connection Diagrams and Ordering Information
TO-263 Surface-Mount Package
Order Number LM2937ET-2.5, LM2937ET-3.3,
See NS Package Number T03B
TO-220 Plastic Package
Front View
Top View
Order Number LM2937ES-2.5, LM2937ES-3.3,
See NS Package Number TS3B
two-battery jumps and up to +60V/−50V load dump tran-
sients. Familiar regulator features such as short circuit and
thermal shutdown protection are also built in.
n Fully specified for operation over −40˚C to +125˚C
n Output current in excess of 500 mA (400mA for
n Output trimmed for 5% tolerance under all operating
n Wide output capacitor ESR range, 0.01Ω up to 5Ω
n Internal short circuit and thermal overload protection
n Reverse battery protection
n 60V input transient protection
n Mirror image insertion protection
SOT-223 package)
Order Number LM2937IMP-2.5, LM2937IMP-3.3,
See NS Package Number MA04A
SOT-223 Plastic Package
Front View
Side View
August 2005

LM2937ES-3.3/NOPB Summary of contents

Page 1

... Internal short circuit and thermal overload protection n Reverse battery protection n 60V input transient protection n Mirror image insertion protection 10011324 Order Number LM2937IMP-2.5, LM2937IMP-3.3, See NS Package Number MA04A 10011326 Order Number LM2937ES-2.5, LM2937ES-3.3, See NS Package Number TS3B DS100113 August 2005 SOT-223 Plastic Package 10011325 Front View 10011327 Side View www ...

Page 2

... The small physical size of the SOT-223 package does not allow sufficient space to provide the complete device part number. The actual devices will be labeled with the package markings shown. www.national.com Output Voltage 2.5 3.3 LM2937ES-2.5 LM2937ES-3.3 LM2937ET-2.5 LM2937ET-3.3 LM2937IMP-2.5 LM2937IMP-3.3 L68B L69B ...

Page 3

... J (Note 1) SOT-223 (Vapor Phase, 60 seconds) 215˚C SOT-223 (Infrared, 15 seconds) ESD Susceptibility (Note 3) Operating Conditions 26V Temperature Range (Note 2) 60V LM2937ES, LM2937ET Internally Limited 150˚C −65˚C to +150˚C LM2937IMP Input Voltage Range 260˚C 230˚C (Note 25˚ ...

Page 4

Electrical Characteristics Note 5: The minimum input voltage required for proper biasing of these regulators is 4.75V. Below this level the outputs will fall out of regulation. This effect is not the normal dropout characteristic where the output falls out ...

Page 5

Typical Performance Characteristics Line Transient Response Ripple Rejection Maximum Power Dissipation (TO-220) (Continued) Load Transient Response 10011308 10011310 Maximum Power Dissipation 10011312 5 10011309 Output Impedance 10011311 (TO-263) (Note 2) 10011313 www.national.com ...

Page 6

Typical Performance Characteristics Low Voltage Behavior (2.5V) Output at Voltage Extremes Peak Output Current www.national.com (Continued) Low Voltage Behavior (3.3) 10011314 10011316 10011318 6 10011315 Output Capacitor ESR 10011317 ...

Page 7

Typical Application * Required if the regulator is located more than 3 inches from the power supply filter capacitors. ** Required for stability. C must be at least 10 µF (over the full expected operating temperature range) and located as ...

Page 8

Application Hints EXTERNAL CAPACITORS The output capacitor is critical to maintaining regulator sta- bility, and must meet the required conditions for both ESR (Equivalent Series Resistance) and minimum amount of ca- pacitance. MINIMUM CAPACITANCE: The minimum output capacitance required to ...

Page 9

Application Hints (Continued) When a value for θ is found using the equation shown, (H−A) a heatsink must be selected that has a value that is less than or equal to this number. θ is specified numerically by the heatsink ...

Page 10

... Physical Dimensions www.national.com inches (millimeters) unless otherwise noted Plastic Package Order Number LM2937ET-2.5, LM2937ET-3.3, NS Package Number T03B TO-263 3-Lead Plastic Surface Mount Package Order Number LM2937ES-2.5, LM2937ES-3.3, NS Package Number TS3B 10 ...

Page 11

... BANNED SUBSTANCE COMPLIANCE National Semiconductor manufactures products and uses packing materials that meet the provisions of the Customer Products Stewardship Specification (CSP-9-111C2) and the Banned Substances and Materials of Interest Specification (CSP-9-111S2) and contain no ‘‘Banned Substances’’ as defined in CSP-9-111S2. ...

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