LM301ANNOPB - NATIONAL SEMICONDUCTOR

LM2940,LM2940C

LM2940/LM2940C 1A Low Dropout Regulator

Literature Number: SNVS769H

January 2007

LM2940/LM2940C

1A Low Dropout Regulator

General Description

The LM2940/LM2940C positive voltage regulator features the

ability to source 1A of output current with a dropout voltage of

typically 0.5V and a maximum of 1V over the entire temper-

ature range. Furthermore, a quiescent current reduction cir-

cuit has been included which reduces the ground current

when the differential between the input voltage and the output

voltage exceeds approximately 3V. The quiescent current

with 1A of output current and an input-output differential of 5V

is therefore only 30 mA. Higher quiescent currents only exist

when the regulator is in the dropout mode (VIN − VOUT ≤ 3V).

Designed also for vehicular applications, the LM2940/

LM2940C and all regulated circuitry are protected from re-

verse battery installations or 2-battery jumps. During line

transients, such as load dump when the input voltage can

momentarily exceed the specified maximum operating volt-

age, the regulator will automatically shut down to protect both

the internal circuits and the load. The LM2940/LM2940C can-

not be harmed by temporary mirror-image insertion. Familiar

regulator features such as short circuit and thermal overload

protection are also provided.

Features

■Dropout voltage typically 0.5V @IO = 1A

■Output current in excess of 1A

■Output voltage trimmed before assembly

■Reverse battery protection

■Internal short circuit current limit

■Mirror image insertion protection

■P+ Product Enhancement tested

Typical Application

882203

*Required if regulator is located far from power supply filter.

**COUT must be at least 22 μF to maintain stability. May be increased without bound to maintain regulation during transients. Locate as close as possible to

the regulator. This capacitor must be rated over the same operating temperature range as the regulator and the ESR is critical; see curve.

Ordering Information

Temp

Range

Output Voltage Package

5.0 8.0 9.0 10 12 15

0°C

≤ TJ ≤

125°C

LM2940CT-5.0 –LM2940CT-9.0 –LM2940CT-12 LM2940CT-15 TO-220

LM2940CS-5.0 –LM2940CS-9.0 –LM2940CS-12 LM2940CS-15

TO-263

LM2940CSX

-5.0 –LM2940CSX

-9.0 –LM2940CSX

-12

LM2940CSX

-15

−40°C

≤ TJ ≤

125°C

LM2940LD-5.0 LM2940LD-8.0 LM2940LD-9.0 LM2940LD-10 LM2940LD-12 LM2940LD-15

LLP

1k Units

Tape and

Reel

LM2940LDX

-5.0

LM2940LDX

-8.0

LM2940LDX

-9.0

LM2940LDX

-10

LM2940LDX

-12

LM2940LDX

-15

LLP

4.5k

Units

Tape and

Reel

−40°C

≤ TJ ≤

125°C

LM2940T-5.0 LM2940T-8.0 LM2940T-9.0 LM2940T-10 LM2940T-12 –TO-220

LM2940S-5.0 LM2940S-8.0 LM2940S-9.0 LM2940S-10 LM2940S-12 –TO-263

LM2940SX-5.0 LM2940SX-8.0 LM2940SX-9.0 LM2940SX-10 LM2940SX-12 –

LM2940/LM2940C 1A Low Dropout Regulator

Temp

Range

Output Voltage Package

5.0 8.0 9.0 10 12 15

−40°C

≤ TA ≤

85°C

LM2940IMP-5.0 LM2940IMP-8.0 LM2940IMP-9.0 LM2940IMP-10 LM2940IMP-12 LM2940IMP-15 SOT-223

LM2940IMPX

-5.0

LM2940IMPX

-8.0

LM2940IMPX

-9.0

LM2940IMPX

-10

LM2940IMPX

-12

LM2940IMPX

-15

SOT-223

in Tape

and Reel

Marking L53B L54B L0EB L55B L56B L70B

The physical size of the SOT-223 is too small to contain the full device part number. The package markings indicated are what will appear on the actual device.

Mil-Aero Ordering Information

Temperature

Range

Output Voltage Package

5.0 8.0 12 15

−55°C

≤ TJ ≤

125°C

LM2940J-5.0/883

5962-8958701EA –LM2940J-12/883

5962-9088401QEA

LM2940J-15/883

5962-9088501QEA J16A

LM2940WG5.0/883

5962-8958701XA –LM2940WG5-12/883 LM2940WG5-15/883 WG16A

For information on military temperature range products, please go to the Mil/Aero Web Site at http://www.national.com/appinfo/milaero/index.html.

Connection Diagrams

TO-220 (T) Plastic Package

882202

Front View

See NS Package Number TO3B

SOT-223 (MP) 3-Lead

882242

Front View

See NS Package Number MP04A

16-Lead Dual-in-Line Package (J)

882243

Top View

See NS Package Number J16A

16-Lead Ceramic Surface-Mount Package (WG)

882244

Top View

See NS Package Number WG16A

TO-263 (S) Surface-Mount Package

882211

Top View

LLP (LD) 8-Lead

882246

Pin 2 and pin 7 are fused to center DAP

Pin 5 and 6 need to be tied together on PCB board

Top View

See NS Package Number LDC08A

882212

Side View

See NS Package Number TS3B

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LM2940/LM2940C

Absolute Maximum Ratings (Note 1)

If Military/Aerospace specified devices are required,

please contact the National Semiconductor Sales Office/

Distributors for availability and specifications.

LM2940S, J, WG, T, MP ≤ 100

ms 60V

LM2940CS, T ≤ 1 ms 45V

Internal Power Dissipation

(Note 2) Internally Limited

Maximum Junction Temperature 150°C

Storage Temperature Range −65°C ≤ TJ ≤ +150°C

Soldering Temperature (Note 3)

TO-220 (T), Wave 260°C, 10s

TO-263 (S) 235°C, 30s

SOT-223 (MP) 260°C, 30s

LLP-8 (LD) 235°C, 30s

ESD Susceptibility (Note 4) 2 kV

Operating Conditions (Note 1)

Input Voltage 26V

Temperature Range

LM2940T, LM2940S −40°C ≤ TJ ≤ 125°C

LM2940CT, LM2940CS 0°C ≤ TJ ≤ 125°C

LM2940IMP −40°C ≤ TA ≤ 85°C

LM2940J, LM2940WG −55°C ≤ TJ ≤ 125°C

LM2940LD −40°C ≤ TJ ≤ 125°C

Electrical Characteristics

VIN = VO + 5V, IO = 1A, CO = 22 μF, unless otherwise specified. Boldface limits apply over the entire operating temperature

range of the indicated device. All other specifications apply for TA = TJ = 25°C.

Output Voltage (VO) 5V 8V

Units

LM2940 LM2940/883 LM2940 LM2940/883

Parameter Conditions Typ Limit Limit Typ Limit Limit

(Note 5) (Note 6) (Note 5) (Note 6)

6.25V ≤ VIN ≤ 26V 9.4V ≤ VIN ≤ 26V

Output Voltage 5 mA ≤ IO ≤ 1A 5.00 4.85/4.75 4.85/4.75 8.00 7.76/7.60 7.76/7.60 VMIN

5.15/5.25 5.15/5.25 8.24/8.40 8.24/8.40 VMAX

Line Regulation VO + 2V ≤ VIN ≤ 26V, 20 50 40/50 20 80 50/80 mVMAX

IO = 5 mA

Load Regulation 50 mA ≤ IO ≤ 1A

LM2940, LM2940/883 35 50/80 50/100 55 80/130 80/130 mVMAX

LM2940C 35 50 55 80

Output 100 mADC and

Impedance 20 mArms, 35 1000/1000 55 1000/1000 mΩ

fO = 120 Hz

Quiescent VO +2V ≤ VIN ≤ 26V,

Current IO = 5 mA

LM2940, LM2940/883 10 15/20 15/20 10 15/20 15/20 mAMAX

LM2940C 10 15

VIN = VO + 5V, 30 45/60 50/60 30 45/60 50/60 mAMAX

IO = 1A

Output Noise 10 Hz − 100 kHz, 150 700/700 240 1000/1000 μVrms

Voltage IO = 5 mA

Ripple Rejection fO = 120 Hz, 1 Vrms,

IO = 100 mA

LM2940 72 60/54 66 54/48 dBMIN

LM2940C 72 60 66 54

fO = 1 kHz, 1 Vrms, 60/50 54/48 dBMIN

IO = 5 mA

Long Term 20 32 mV/

Stability 1000 Hr

Dropout Voltage IO = 1A 0.5 0.8/1.0 0.7/1.0 0.5 0.8/1.0 0.7/1.0 VMAX

IO = 100 mA 110 150/200 150/200 110 150/200 150/200 mVMAX

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LM2940/LM2940C

Output Voltage (VO) 5V 8V

Units

LM2940 LM2940/883 LM2940 LM2940/883

Parameter Conditions Typ Limit Limit Typ Limit Limit

(Note 5) (Note 6) (Note 5) (Note 6)

Short Circuit

Current

(Note 7) 1.9 1.6 1.5/1.3 1.9 1.6 1.6/1.3 AMIN

Maximum Line RO = 100Ω

VMIN

Transient LM2940, T ≤ 100 ms 75 60/60 75 60/60

LM2940/883, T ≤ 20 ms 40/40 40/40

LM2940C, T ≤ 1 ms 55 45 55 45

Reverse Polarity RO = 100Ω

DC Input Voltage LM2940, LM2940/883 −30 −15/−15 −15/−15 −30 −15/−15 −15/−15 VMIN

LM2940C −30 −15 −30 −15

Reverse Polarity RO = 100Ω

Transient Input LM2940, T ≤ 100 ms −75 −50/−50 −75 −50/−50 VMIN

Voltage LM2940/883, T ≤ 20 ms −45/−45 −45/−45

LM2940C, T ≤ 1 ms −55 −45/−45

Electrical Characteristics

VIN = VO + 5V, IO = 1A, CO = 22 μF, unless otherwise specified. Boldface limits apply over the entire operating temperature

range of the indicated device. All other specifications apply for TA = TJ = 25°C.

Output Voltage (VO) 9V 10V

Units

Parameter Conditions Typ

LM2940

Typ

LM2940

Limit Limit

(Note 5) (Note 5)

10.5V ≤ VIN ≤ 26V 11.5V ≤ VIN ≤ 26V

Output Voltage 5 mA ≤ IO ≤1A 9.00 8.73/8.55 10.00 9.70/9.50 VMIN

9.27/9.45 10.30/10.50 VMAX

Line Regulation VO + 2V ≤ VIN ≤ 26V, 20 90 20 100 mVMAX

IO = 5 mA

Load Regulation 50 mA ≤ IO ≤ 1A

LM2940 60 90/150 65 100/165 mVMAX

LM2940C 60 90

Output Impedance 100 mADC and

20 mArms, 60 65 mΩ

fO = 120 Hz

Quiescent VO +2V ≤ VIN < 26V,

Current IO = 5 mA

LM2940 10 15/20 10 15/20 mAMAX

LM2940C 10 15

VIN = VO + 5V, IO = 1A 30 45/60 30 45/60 mAMAX

Output Noise 10 Hz − 100 kHz, 270 300 μVrms

Voltage IO = 5 mA

Ripple Rejection fO = 120 Hz, 1 Vrms,

IO = 100 mA

LM2940 64 52/46 63 51/45 dBMIN

LM2940C 64 52

Long Term

Stability

34 36 mV/

1000 Hr

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LM2940/LM2940C

Output Voltage (VO) 9V 10V

Units

Parameter Conditions Typ

LM2940

Typ

LM2940

Limit Limit

(Note 5) (Note 5)

Dropout Voltage IO = 1A 0.5 0.8/1.0 0.5 0.8/1.0 VMAX

IO = 100 mA 110 150/200 110 150/200 mVMAX

Short Circuit (Note 7) 1.9 1.6 1.9 1.6 AMIN

Current

Maximum Line RO = 100Ω

Transient T ≤ 100 ms

LM2940 75 60/60 75 60/60 VMIN

LM2940C 55 45

Reverse Polarity RO = 100Ω

DC Input Voltage LM2940 −30 −15/−15 −30 −15/−15 VMIN

LM2940C −30 −15

Reverse Polarity RO = 100Ω

Transient Input T ≤ 100 ms

Voltage LM2940 −75 −50/−50 −75 −50/−50 VMIN

LM2940C −55 −45/−45

Electrical Characteristics

VIN = VO + 5V, IO = 1A, CO = 22 μF, unless otherwise specified. Boldface limits apply over the entire operating temperature

range of the indicated device. All other specifications apply for TA = TJ = 25°C.

Output Voltage (VO) 12V 15V

Units

LM2940 LM2940/833 LM2940 LM2940/833

Parameter Conditions Typ Limit Limit Typ Limit Limit

(Note 5) (Note 6) (Note 5) (Note 6)

13.6V ≤ VIN ≤ 26V 16.75V ≤ VIN ≤ 26V

Output Voltage 5 mA ≤ IO ≤1A 12.00 11.64/11.40 11.64/11.40 15.00 14.55/14.25 14.55/14.25 VMIN

12.36/12.60 12.36/12.60 15.45/15.75 15.45/15.75 VMAX

Line Regulation VO + 2V ≤ VIN ≤ 26V, 20 120 75/120 20 150 95/150 mVMAX

IO = 5 mA

Load Regulation 50 mA ≤ IO ≤ 1A

LM2940, LM2940/883 55 120/200 120/190 150/240 mVMAX

LM2940C 55 120 70 150

Output 100 mADC and

Impedance 20 mArms, 80 1000/1000 100 1000/1000 mΩ

fO = 120 Hz

Quiescent

Current

VO +2V ≤ VIN ≤ 26V,

IO = 5 mA

LM2940, LM2940/883 10 15/20 15/20 15/20 mAMAX

LM2940C 10 15 10 15

VIN = VO + 5V, IO = 1A 30 45/60 50/60 30 45/60 50/60 mAMAX

Output Noise 10 Hz − 100 kHz, 360 1000/1000 450 1000/1000 μVrms

Voltage IO = 5 mA

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LM2940/LM2940C

Output Voltage (VO) 12V 15V

Units

LM2940 LM2940/833 LM2940 LM2940/833

Parameter Conditions Typ Limit Limit Typ Limit Limit

(Note 5) (Note 6) (Note 5) (Note 6)

Ripple Rejection fO = 120 Hz, 1 Vrms,

IO = 100 mA

LM2940 66 54/48 dBMIN

LM2940C 66 54 64 52

fO = 1 kHz, 1 Vrms, 52/46 48/42 dBMIN

IO = 5 mA

Long Term 48 60 mV/

Stability 1000 Hr

Dropout Voltage IO = 1A 0.5 0.8/1.0 0.7/1.0 0.5 0.8/1.0 0.7/1.0 VMAX

IO = 100 mA 110 150/200 150/200 110 150/200 150/200 mVMAX

Short Circuit (Note 7) 1.9 1.6 1.6/1.3 1.9 1.6 1.6/1.3 AMIN

Current

Maximum Line RO = 100Ω

Transient LM2940, T ≤ 100 ms 75 60/60

LM2940/883, T ≤ 20 ms 40/40 40/40 VMIN

LM2940C, T ≤ 1 ms 55 45 55 45

Reverse Polarity RO = 100Ω

DC Input LM2940, LM2940/883 −30 −15/−15 −15/−15 −15/−15 VMIN

Voltage LM2940C −30 −15 −30 −15

Reverse Polarity RO = 100Ω

Transient Input LM2940, T ≤ 100 ms −75 −50/−50

Voltage LM2940/883, T ≤ 20 ms −45/−45 −45/−45 VMIN

LM2940C, T ≤ 1 ms −55 −45/−45 −55 −45/−45

Thermal Performance

Thermal Resistance

Junction-to-Case, θ(JC)

3-Lead TO-220 4 °C/W

3-Lead TO-263 4

Thermal Resistance

Junction-to-Ambient, θ(JA)

3-Lead TO-220 (Note 2) 60

°C/W

3-Lead TO-263 (Note 2) 80

SOT-223(Note 2) 174

8-Lead LLP (Note 2) 35

Note 1: Absolute Maximum Ratings are limits beyond which damage to the device may occur. Operating Conditions are conditions under which the device

functions but the specifications might not be guaranteed. For guaranteed specifications and test conditions see the Electrical Characteristics.

Note 2: The maximum allowable power dissipation is a function of the maximum junction temperature, TJ, the junction-to-ambient thermal resistance, θJA, and

the ambient temperature, TA. Exceeding the maximum allowable power dissipation will cause excessive die temperature, and the regulator will go into thermal

shutdown. The value of θJA (for devices in still air with no heatsink) is 60°C/W for the TO-220 package, 80°C/W for the TO-263 package, and 174°C/W for the

SOT-223 package. The effective value of θJA can be reduced by using a heatsink (see Application Hints for specific information on heatsinking). The value of

θJA for the LLP package is specifically dependent on PCB trace area, trace material, and the number of layers and thermal vias. For improved thermal resistance

and power dissipation for the LLP package, refer to Application Note AN-1187. It is recommended that 6 vias be placed under the center pad to improve thermal

performance.

Note 3: Refer to JEDEC J-STD-020C for surface mount device (SMD) package reflow profiles and conditions. Unless otherwise stated, the temperature and time

are for Sn-Pb (STD) only.

Note 4: ESD rating is based on the human body model, 100 pF discharged through 1.5 kΩ.

Note 5: All limits are guaranteed at TA = TJ = 25°C only (standard typeface) or over the entire operating temperature range of the indicated device (boldface type).

All limits at TA = TJ = 25°C are 100% production tested. All limits at temperature extremes are guaranteed via correlation using standard Statistical Quality Control

methods.

Note 6: All limits are guaranteed at TA = TJ = 25°C only (standard typeface) or over the entire operating temperature range of the indicated device (boldface type).

All limits are 100% production tested and are used to calculate Outgoing Quality Levels.

Note 7: Output current will decrease with increasing temperature but will not drop below 1A at the maximum specified temperature.

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LM2940/LM2940C

Typical Performance Characteristics

Dropout Voltage

882213

Dropout Voltage vs. Temperature

882214

Output Voltage vs. Temperature

882215

Quiescent Current vs. Temperature

882216

Quiescent Current

882217

Quiescent Current

882218

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LM2940/LM2940C

Line Transient Response

882219

Load Transient Response

882220

Ripple Rejection

882221

Low Voltage Behavior

882225

Low Voltage Behavior

882226

Low Voltage Behavior

882227

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LM2940/LM2940C

Low Voltage Behavior

882228

Low Voltage Behavior

882229

Low Voltage Behavior

882230

Output at Voltage Extremes

882231

Output at Voltage Extremes

882232

Output at Voltage Extremes

882233

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LM2940/LM2940C

Output at Voltage Extremes

882234

Output at Voltage Extremes

882235

Output at Voltage Extremes

882236

Output Capacitor ESR

882206

Peak Output Current

882208

Output Impedance

882222

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LM2940/LM2940C

Maximum Power Dissipation (TO-220)

882223

Maximum Power Dissipation (SOT-223)

882224

Maximum Power Dissipation (TO-263)

882210

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LM2940/LM2940C

Equivalent Schematic Diagram

882201

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LM2940/LM2940C

Application Information

EXTERNAL CAPACITORS

The output capacitor is critical to maintaining regulator stabil-

ity, 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 maintain stabil-

ity is 22 μF (this value may be increased without limit). Larger

values of output capacitance will give improved transient re-

sponse.

ESR LIMITS:

The ESR of the output capacitor will cause loop instability if it

is too high or too low. The acceptable range of ESR plotted

versus load current is shown in the graph below. It is essen-

tial that the output capacitor meet these requirements, or

oscillations can result.

Output Capacitor ESR

882206

FIGURE 1. ESR Limits

It is important to note that for most capacitors, ESR is speci-

fied only at room temperature. However, the designer must

ensure that the ESR will stay inside the limits shown over the

entire operating temperature range for the design.

For aluminum electrolytic capacitors, ESR will increase by

about 30X as the temperature is reduced from 25°C to −40°

C. This type of capacitor is not well-suited for low temperature

operation.

Solid tantalum capacitors have a more stable ESR over tem-

perature, but are more expensive than aluminum electrolyt-

ics. A cost-effective approach sometimes used is to parallel

an aluminum electrolytic with a solid Tantalum, with the total

capacitance split about 75/25% with the Aluminum being the

larger value.

If two capacitors are paralleled, the effective ESR is the par-

allel of the two individual values. The “flatter” ESR of the

Tantalum will keep the effective ESR from rising as quickly at

low temperatures.

HEATSINKING

A heatsink may be required depending on the maximum pow-

er dissipation and maximum ambient temperature of the ap-

plication. Under all possible operating conditions, the junction

temperature must be within the range specified under Abso-

lute Maximum Ratings.

To determine if a heatsink is required, the power dissipated

by the regulator, PD, must be calculated.

The figure below shows the voltages and currents which are

present in the circuit, as well as the formula for calculating the

power dissipated in the regulator:

882237

IIN = IL + IG

PD = (VIN − VOUT) IL + (VIN) IG

FIGURE 2. Power Dissipation Diagram

The next parameter which must be calculated is the maximum

allowable temperature rise, TR(MAX). This is calculated by us-

ing the formula:

TR(MAX) = TJ(MAX) − TA(MAX)

where: TJ(MAX) is the maximum allowable junction tempera-

ture, which is 125°C for commercial grade

parts.

TA(MAX) is the maximum ambient temperature which

will be encountered in the application.

Using the calculated values for TR(MAX) and PD, the maximum

allowable value for the junction-to-ambient thermal resis-

tance, θ(JA), can now be found:

θ(JA) = TR(MAX) / PD

IMPORTANT: If the maximum allowable value for θ(JA) is

found to be ≥ 53°C/W for the TO-220 package, ≥ 80°C/W for

the TO-263 package, or ≥ 174°C/W for the SOT-223 pack-

age, no heatsink is needed since the package alone will

dissipate enough heat to satisfy these requirements.

If the calculated value for θ(JA)falls below these limits, a

heatsink is required.

HEATSINKING TO-220 PACKAGE PARTS

The TO-220 can be attached to a typical heatsink, or secured

to a copper plane on a PC board. If a copper plane is to be

used, the values of θ(JA) will be the same as shown in the next

section for the TO-263.

If a manufactured heatsink is to be selected, the value of

heatsink-to-ambient thermal resistance, θ(H−A), must first be

calculated:

θ(H−A) = θ(JA) − θ(C−H) − θ(J−C)

Where: θ(J−C) is defined as the thermal resistance from the

junction to the surface of the case. A value of

3°C/W can be assumed for θ(J−C) for this cal-

culation.

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LM2940/LM2940C

θ(C−H) is defined as the thermal resistance between

the case and the surface of the heatsink. The

value of θ(C−H) will vary from about 1.5°C/W to

about 2.5°C/W (depending on method of at-

tachment, insulator, etc.). If the exact value is

unknown, 2°C/W should be assumed for θ(C

−H).

When a value for θ(H−A) is found using the equation shown, a

heatsink must be selected that has a value that is less than

or equal to this number.

θ(H−A) is specified numerically by the heatsink manufacturer

in the catalog, or shown in a curve that plots temperature rise

vs power dissipation for the heatsink.

HEATSINKING TO-263 PACKAGE PARTS

The TO-263 (“S”) package uses a copper plane on the PCB

and the PCB itself as a heatsink. To optimize the heat sinking

ability of the plane and PCB, solder the tab of the package to

the plane.

Figure 3 shows for the TO-263 the measured values of θ(JA)

for different copper area sizes using a typical PCB with 1

ounce copper and no solder mask over the copper area used

for heatsinking.

882238

FIGURE 3. θ(JA) vs. Copper (1 ounce) Area for the TO-263

Package

As shown in the figure, increasing the copper area beyond 1

square inch produces very little improvement. It should also

be observed that the minimum value of θ(JA) for the TO-263

package mounted to a PCB is 32°C/W.

As a design aid, Figure 4 shows the maximum allowable pow-

er dissipation compared to ambient temperature for the

TO-263 device. This assumes a θ(JA) of 35°C/W for 1 square

inch of 1 ounce copper and a maximum junction temperature

(TJ) of 125°C.

882239

FIGURE 4. Maximum Power Dissipation vs. TA for the

TO-263 Package

HEATSINKING SOT-223 PACKAGE PARTS

The SOT-223 (“MP”) packages use a copper plane on the

PCB and the PCB itself as a heatsink. To optimize the heat

sinking ability of the plane and PCB, solder the tab of the

package to the plane.

Figure 5 and Figure 6 show the information for the SOT-223

package. Figure 6 assumes a θ(JA) of 74°C/W for 1 square

inch of 1 ounce copper and 51°C/W for 1 square inch of 2

ounce copper, with a maximum ambient temperature (TA) of

85°C and a maximum junction temperature (TJ) of 125°C.

For techniques for improving the thermal resistance and pow-

er dissipation for the SOT-223 package, please refer to Ap-

plication Note AN-1028.

882240

FIGURE 5. θ(JA) vs. Copper (2 ounce) Area for the SOT-223

Package

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LM2940/LM2940C

882241

FIGURE 6. Maximum Power Dissipation vs. TA for the

SOT-223 Package

HEATSINKING LLP PACKAGE PARTS

The value of θJA for the LLP package is specifically dependent

on PCB trace area, trace material, and the number of layers

and thermal vias. It is recommended that a minimum of 6

thermal vias be placed under the center pad to improve ther-

mal performance.

For techniques for improving the thermal resistance and pow-

er dissipation for the LLP package, please refer to Application

Note AN-1187.

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LM2940/LM2940C

Physical Dimensions inches (millimeters) unless otherwise noted

3-Lead SOT-223 Package

NS Package Number MP04A

16 Lead Dual-in-Line Package (J)

See NS Package Number J16A

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LM2940/LM2940C

16 Lead Surface Mount Package (WG)

See NS Package Number WG16A

3-Lead TO-220 Plastic Package (T)

NS Package Number TO3B

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LM2940/LM2940C

3-Lead TO-263 Surface Mount Package (MP)

NS Package Number TS3B

8-Lead LLP

Order Number LM2940LD-5.0, LM2940LD-8.0,

LM2940LD-9.0, LM2940LD-10,

LM2940LD-12 or LM2940LD-15

NS Package Number LDC08A

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LM2940/LM2940C

Notes

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LM2940/LM2940C

Notes

LM2940/LM2940C 1A Low Dropout Regulator

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