National Semiconductor LM2931 Technical data

LM2931
Series Low Dropout Regulators

General Description

The LM2931 positive voltage regulator features a very low
quiescent current of 1mA or less when supplying 10mA
loads. This unique characteristic and the extremely low
input-output differential required for proper regulation (0.2V
for output currents of 10mA) make the LM2931 the ideal
regulator for standby power systems. Applications include
memory standby circuits, CMOS and other low power pro­cessor power supplies as well as systems demanding as
much as 100mA of output current.

Designed originally for automotive applications, the LM2931
and all regulated circuitry are protected from reverse battery
installations or 2 battery jumps. During line transients, such
as a load dump (60V) when the input voltage to the regulator
can momentarily exceed the specified maximum operating
voltage, the regulator will automatically shut down to protect
both internal circuits and the load. The LM2931 cannot be
harmed by temporary mirror-image insertion. Familiar regu­lator features such as short circuit and thermal overload
protection are also provided.

±

The LM2931 family includes a fixed 5V output (
ance for A grade) or an adjustable output with ON/OFF pin.

3.8% toler-

Both versions are available in a TO-220 power package,
TO-263 surface mount package, and an 8-lead surface
mount package. The fixed output version is also available in
the TO-92 plastic and 6-Bump micro SMD packages.

Features

n Very low quiescent current
n Output current in excess of 100 mA
n Input-output differential less than 0.6V
n Reverse battery protection
n 60V load dump protection
n −50V reverse transient protection
n Short circuit protection
n Internal thermal overload protection
n Mirror-image insertion protection
n Available in TO-220, TO-92, TO-263, SO-8 or 6-Bump

n Available as adjustable with TTL compatible switch
n See AN-1112 for micro SMD considerations

LM2931 Series Low Dropout Regulators

June 2005

micro SMD packages

Connection Diagrams

FIXED VOLTAGE OUTPUT

TO-220 3-Lead Power Package

00525406

Front View

8-Pin Surface Mount TO-92 Plastic Package

00525407

*NC = Not internally connected. Must be electrically isolated from the rest
of the circuit for the micro SMD package.

Top View

TO-263 Surface-Mount Package

00525411

Top View

00525412

Side View

00525408

Bottom View

© 2005 National Semiconductor Corporation DS005254 www.national.com

Connection Diagrams (Continued)

LM2931

6-Bump micro SMD micro SMD Laser Mark

(Bump Side Down)

ADJUSTABLE OUTPUT VOLTAGE

TO-220 5-Lead Power Package

Top View

Front View

00525438

00525409

00525439

TO-263

5-Lead Surface-Mount Package

00525413

Top View

8-Pin Surface Mount

00525410

Top View

00525414

Side View

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Ordering Information

Output

Number

5V 3-Pin TO-220 LM2931T-5.0 LM2931T-5.0 Rails T03B

Adjustable,
3V to 24V

3.3V

Note: The micro SMD package marking is a single digit manufacturing Date

Code Only.

Package Part Number Package Marking Transport Media NSC Drawing

LM2931AT-5.0 LM2931AT-5.0 Rails

3-Pin TO-263 LM2931S-5.0 LM2931S-5.0 Rails TS3B

LM2931AS-5.0 LM2931AS-5.0 Rails

TO-92 LM2931Z-5.0 LM2931Z-5 1.8k Units per Box Z03A

LM2931AZ-5.0 LM2931AZ 1.8k Units per Box

8-Pin
SOIC

*

6-Bump

micro SMD

5-Pin TO-220 LM2931CT LM2931CT Rails T05A

5-Pin TO-263 LM2931CS LM2931CS Rails TS5B

8-Pin
SOIC

*

6-Bump

micro SMD

LM2931M-5.0 2931M-5.0 Rails M08A

LM2931AM-5.0 2931AM-5.0 Rails

LM2931IBPX-5.0 - Tape and Reel BPA06HTA

LM2931CM LM2931CM Rails M08A

LM2931IBPX-3.3 - Tape and Reel BPA06HTB

LM2931

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Typical Applications

LM2931

LM2931 Fixed Output

*

Required if regulator is located far from power supply filter.

*

*C2 must be at least 100 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. The equivalent series resistance (ESR) of this capacitor is
critical; see curve.

00525404

LM2931 Adjustable Output

00525405

Note: Using 27k for R1 will automatically compensate for errors in V

due to the input bias current of the ADJ pin (approximately 1 µA).

OUT

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LM2931

Absolute Maximum Ratings (Note 1)

If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.

Input Voltage

Operating Range 26V

Overvoltage Protection

LM2931A, LM2931C

Internal Power Dissipation

(Note 2) (Note 4) Internally Limited

Operating Ambient Temperature

Range −40˚C to +85˚C

Maximum Junction Temperature 125˚C

Storage Temperature Range −65˚C to +150˚C

Lead Temp. (Soldering, 10 seconds) 230˚C

ESD Tolerance (Note 5) 2000V

(Adjustable) 60V

LM2931 50V

Electrical Characteristics for Fixed 3.3V Version

VIN= 14V, IO= 10mA, TJ= 25˚C, C2= 100µF (unless otherwise specified) (Note 2)

Parameter Conditions LM2931-3.3 Units

Typ Limit

(Note 3)

Output Voltage 3.3 3.465

3.135

4V ≤ VIN≤ 26V, IO= 100 mA

−40˚C ≤ T

≤ 125˚C

J

3.630

2.970

Line Regulation 4V ≤ VIN≤ 26V 4 33 mV

Load Regulation 5mA ≤ IO≤ 100mA 10 50 mV

Output Impedance 100mADCand 10mA

rms

,

200 mΩ

100Hz - 10kHz

Quiescent Current I

≤ 10mA, 4V ≤ VIN≤ 26V 0.4 1.0 mA

O

−40˚C ≤ TJ≤ 125˚C

I

= 100mA, VIN= 14V, TJ= 25˚C 15 mA

O

Output Noise Voltage 10Hz -100kHz, C

= 100µF 330 µV

OUT

Long Term Stability 13 mV/1000 hr

Ripple Rejection f

Dropout Voltage I

Maximum Operational Input

= 120Hz 80 dB

O

= 10mA

O

= 100mA

I

O

0.05

0.30

0.2

0.6

33 26 V

Voltage

Maximum Line Transient RL= 500Ω,VO≤ 5.5V,

70 50 V

T = 1ms, τ≤100ms

Reverse Polarity Input

VO≥ −0.3V, RL= 500Ω −30 −15 V

Voltage, DC

Reverse Polarity Input

T = 1ms, τ≤100ms, RL= 500Ω −80 −50 V

Voltage, Transient

V

MAX

V

MIN

V

MAX

V

MIN

MAX

MAX

MAX

rms

V

MAX

MIN

MIN

MIN

MIN

Electrical Characteristics for Fixed 5V Version

VIN= 14V, IO= 10mA, TJ= 25˚C, C2 = 100 µF (unless otherwise specified) (Note 2)

Parameter Conditions LM2931A-5.0 LM2931-5.0 Units

Typ

Output Voltage 5 5.19

Limit

(Note 3)

Typ

5 5.25

4.81

6.0V ≤ VIN≤ 26V, IO= 100mA

−40˚C ≤ T

≤ 125˚C

J

Line Regulation 9V ≤ VIN≤ 16V

IN

≤ 26V

6V ≤ V

2
4

5.25

4.75

10
30

2
4

Load Regulation 5 mA ≤ IO≤ 100mA 14 50 14 50 mV

Limit

(Note 3)

4.75

5.5

4.5

10
30

V

V

mV

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MAX

V

MIN

MAX

V

MIN

MAX

MAX

Electrical Characteristics for Fixed 5V Version (Continued)

VIN= 14V, IO= 10mA, TJ= 25˚C, C2 = 100 µF (unless otherwise specified) (Note 2)

LM2931

Output Impedance 100mA

Output Noise Voltage 10Hz -100kHz, C

Long Term Stability 20 20 mV/1000

Ripple Rejection f

Dropout Voltage IO= 10mA

Maximum Operational Input
Voltage

Maximum Line Transient RL= 500Ω,VO≤ 5.5V,

Reverse Polarity Input
Voltage, DC

Reverse Polarity Input
Voltage, Transient

Parameter Conditions LM2931A-5.0 LM2931-5.0 Units

and 10mA

DC

rms

Typ

,

200 200 mΩ

Limit

(Note 3)

Typ

Limit

(Note 3)

100Hz -10kHz

Quiescent Current I

≤ 10mA, 6V ≤ VIN≤ 26V 0.4 1.0 0.4 1.0 mA

O

−40˚C ≤ TJ≤ 125˚C

I

= 100mA, VIN= 14V, TJ= 25˚C 15 30

O

15 mA

5

= 100µF 500 500 µV

OUT

= 120 Hz 80 55 80 dB

O

= 100mA

I

O

0.05

0.3

0.2

0.6

0.05

0.3

0.2

0.6

33 26 33 26 V

T = 1ms, τ≤100ms

70 60 70 50 V

VO≥ −0.3V, RL= 500Ω −30 −15 −30 −15 V

T = 1ms, τ≤100ms, RL= 500Ω −80 −50 −80 −50 V

Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Electrical specifications do not apply when operating the device
beyond its rated operating conditions.

Note 2: See circuit in Typical Applications. To ensure constant junction temperature, low duty cycle pulse testing is used.

Note 3: All limits are guaranteed for T

Note 4: The maximum power dissipation is a function of maximum junction temperature T

maximum allowable power dissipation at any ambient temperature is P
and the LM2931 will go into thermal shutdown. For the LM2931 in the TO-92 package, θ
package, θ
sink, θ

If the TO-263 package is used, the thermal resistance can be reduced by increasing the P.C. board copper area thermally connected to the package: Using 0.5
square inches of copper area, θ

Note 5: Human body model, 100 pF discharged through 1.5 kΩ.

is 50˚C/W; in the TO-263 package, θJAis 73˚C/W; and in the 6-Bump micro SMD package θJAis 290˚C/W. If the TO-220 package is used with a heat

JA

is the sum of the package thermal resistance junction-to-case of 3˚C/W and the thermal resistance added by the heat sink and thermal interface.

JA

= 25˚C (standard type face) or over the full operating junction temperature range of −40˚C to +125˚C (bold type face).

J

=(T

D

is 50˚C/W; with 1 square inch of copper area, θJAis 37˚C/W; and with 1.6 or more square inches of copper area, θJAis 32˚C/W.

JA

)/θJA. If this dissipation is exceeded, the die temperature will rise above 150˚C

Jmax−TA

, total thermal resistance θJA, and ambient temperature TA. The

Jmax

is 195˚C/W; in the SO-8 package, θJAis 160˚C/W, and in the TO-220

JA

mA

V

MAX

MAX

MIN

rms

hr

MIN

MAX

MIN

MIN

MIN

MIN

Electrical Characteristics for Adjustable Version

VIN= 14V, V

Parameter Conditions Typ Limit Units

Reference Voltage 1.20 1.26 V

Output Voltage Range 24 V

Line Regulation V

Load Regulation 5 mA ≤ IO≤ 100 mA 0.3 1 %

Output Impedance 100 mADCand 10 mA

Quiescent Current I

Output Noise Voltage 10 Hz–100 kHz 100 µV

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= 3V, IO= 10 mA, TJ= 25˚C, R1 = 27k, C2 = 100 µF (unless otherwise specified) (Note 2)

OUT

IO≤ 100 mA, −40˚C ≤ Tj≤ 125˚C, R1 = 27k 1.32 V

Measured from V

+ 0.6V ≤ VIN≤ 26V 0.2 1.5 mV/V

OUT

= 10 mA 0.4 1 mA

O

to Adjust Pin 1.08 V

OUT

, 100 Hz–10 kHz 40 mΩ/V

rms

IO= 100 mA 15 mA

During Shutdown R

= 500Ω 0.8 1 mA

L

1.14 V

3V

Limit

MAX

MIN

MAX

MIN

MAX

MIN

MAX

MAX

MAX

rms

MAX

/V