NSC LP2975IMMX-5.0, LP2975IMMX-12, LP2975IMM-5.0, LP2975IMM-12, LP2975AIMMX-3.3 Datasheet

LP2975
MOSFET LDO Driver/Controller

LP2975 MOSFET LDO Driver/Controller

September 1997

General Description

A high-current LDO regulator is simple to design with the
LP2975 LDO Controller. Using an external P-FET, the
LP2975 will deliver an ultra low dropout regulator with ex­tremely low quiescent current.

High open loop gain assures excellent regulation and ripple
rejection performance.

The trimmed internal bandgap reference provides precise
output voltage over the entire operating temperature range.

Dropout voltage is “user selectable” by sizing the external
FET: the minimum input-output voltage required for opera­tion is the maximum load current multiplied by the R
of the FET.

Overcurrent protection of the external FET is easily imple­mented by placing a sense resistor in series with V
57 mV detectionthresholdof the current sense circuitry mini­mizes dropout voltage and power dissipation in the resistor.

The standard product versions available provide output volt­ages of 12V, 5V, or 3.3V with guaranteed 25˚C accuracy of

1.5%(“A” grade) and 2.5%(standard grade).

DS

IN

Features

n Simple to use, few external components
n Ultra-small mini SO-8 package
n 1.5%(A grade) precision output voltage
n Low-power shutdown input

<

n

1 µA in shutdown

n Low operating current (180 µA typical
n Wide supply voltage range (1.8V to 24V)
n Built-in current limit amplifier
n Overtemperature protection
n 12V, 5V, and 3.3V standard output voltages

(ON)

n Can be programmed using external divider
n −40˚C to +125˚C junction temperature range

. The

Applications

n High-current 5V to 3.3V regulator
n Post regulator for switching converter
n Current-limited switch

Block Diagram Connection Diagram

Surface Mount Mini SO-8 Package

Top View

For Order Numbers

See

Table 1

See NS Package Number MUA08A

of this Document

@

VIN= 5V)

DS100034-2

*R

values are: 208k for 12V part, 72.8k for 5V part, and 39.9k for 3.3V

SET

part.

© 1999 National Semiconductor Corporation DS100034 www.national.com

DS100034-1

Ordering Information

TABLE 1. Package Marking and Ordering Information

Output Voltage Grade Order Information Package Marking Supplied As:

12 A LP2975AIMMX-12 L47A 3.5k Units on Tape and Reel
12 A LP2975AIMM-12 L47A 250 Units on Tape and Reel
12 STD LP2975IMMX-12 L47B 3.5k Units on Tape and Reel
12 STD LP2975IMM-12 L47B 250 Units on Tape and Reel

5.0 A LP2975AIMMX-5.0 L46A 3.5k Units on Tape and Reel

5.0 A LP2975AIMM-5.0 L46A 250 Units on Tape and Reel

5.0 STD LP2975IMMX-5.0 L46B 3.5k Units on Tape and Reel

5.0 STD LP2975IMM-5.0 L46B 250 Units on Tape and Reel

3.3 A LP2975AIMMX-3.3 L45A 3.5k Units on Tape and Reel

3.3 A LP2975AIMM-3.3 L45A 250 Units on Tape and Reel

3.3 STD LP2975IMMX-3.3 L45B 3.5k Units on Tape and Reel

3.3 STD LP2975IMM-3.3 L45B 250 Units on Tape and Reel

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Absolute Maximum Ratings (Note 1)

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

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

Range −40˚C to +125˚C

Lead Temp. (Soldering, 5 seconds) 260˚C

Input Supply Voltage (Survival) −0.3V to +26V
Input Supply Voltage (Operating) +1.8V to +24V
Current Limit Pins (Survival) −0.3V to +V
Comp Pin (Survival) −0.3V to +2V
Gate Pin (Survival) −0.3V to +V
ON/OFF Pin (Survival) −0.3V to +20V
Feedback Pin (Survival) −0.3V to +24V

ESD Rating 2 kV
Power Dissipation

(Note 2) Internally Limited

Electrical Characteristics

Limits in standard typeface are for TJ= 25˚C, and limits in boldface type apply over the full operating temperature range. Un­less otherwise specified; V

Symbol Parameter Conditions Typ

V

REG

Regulation Voltage
(12V Versions)

Regulation Voltage
(5V Versions)

Regulation Voltage
(3.3V Versions)

V

COMP

I

Q

V

CL

V

ON/OFF

I

ON/OFF

I

G

Comp Pin Voltage V

Quiescent Current VIN= 5V 180 240 240

Current Limit
Sense Voltage

ON/OFF Threshold Output = ON

ON/OFF
Input Bias Current

Gate Drive Current (Sourcing) VG= 7.5V

Gate Drive Current (Sinking) V

V

R(V

G(MIN)

IN

Gate Clamp Voltage VIN= 24V

-G) Resistance from
Gate to V

IN

Open Loop
Voltage Gain

= 1.5V, VIN= 15V.

ON/OFF

LM2975AI-X.X

(Note 3)

LM2975I-X.X

(Note 3)

Min Max Min Max

IN

- 0.5V)>V

IN

(VIN- 5V)

<

<

V

IN

- 0.5V)>V

IN

(VIN- 4.5V)

<

<

V

IN

- 0.5V)>V

IN

(VIN- 3.3V)

<

V

IN

<

24V 12.0 11.820 12.180 11.700 12.300

GATE

11.640 12.360 11.520 12.480

24V 5.0 4.925 5.075 4.875 5.125

GATE

4.850 5.150 4.800 5.200

24V 3.3 3.250 3.350 3.217 3.383

GATE

<

24V 1.240 1.215 1.265 1.203 1.277

3.201 3.399 3.168 3.432

12.5<V
(V

>

5.5
(V

>

3.8
(V

>

REG

1.209 1.271 1.196 1.284

V

= 0V 0.01 11

ON/OFF

VIN= 15V

=0.9XV

V

FB

Output = OFF

V

= 1.5V

ON/OFF

REG

57 45 69 45 69

39 72 39 72

0.94

0.87

1.10 1.10

1.20 1.20

34

0.70 0.70

0.40 0.40

50 50 µA

75 75

3.5 1.3 1.3

=1.1XV

V

V

FB

G
FB

= 7.5V

=0.9XV

REG

REG

0.3 0.3

1100 350 350

40 40

17 15 19 15 19 V

=0.9XV

V

FB

VIN= 24V
V

ON/OFF

VIN= 15V

0.5V ≤ V

=0

GATE

REG

500 kΩ

5000 V/V

≤ 13

IN

IN

Units

V

V

µA320 320

mV

V

mA

µA

Note 1: Absolute maximum ratings indicate limits beyond which damage to the component may occur. Electrical specifications do not apply when operating the de­vice outside of its rated operating conditions.

Note 2: The LP2975 has internal thermal shutdown which activates at a die temperature of about 150˚C. It should be noted that the power dissipated within the
LP2975 is low enough that this protection circuit should never activate due to self-heating, even at elevated ambient temperatures.

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Electrical Characteristics (Continued)

Note 3: Limits are 100%production tested at 25˚C. Limits over the operating temperature range are guaranteed through correlation using Statistical Quality Control

(SQC) methods. The limits are used to calculate National’s Average Outgoing Quality Level (AOQL).

Typical Application Circuits

5V - 3.3V@5A LDO Regulator

*See Application Hints.
**If current limiting is not required, short out this resistor.

*See Application Hints.

***If current limiting is not required, short out this resistor.

DS100034-3

Adjustable Voltage 5A LDO Regulator

DS100034-4

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Typical Performance Characteristics Unless otherwise specified: T

is tied to 1.5V.

= 25˚C, CIN= 1 µF, ON/OFF pin

A

Minimum Operating Voltage

ON/OFF Threshold

DS100034-5

VINReferred Gate Clamp Voltage

DS100034-6

Current Limit Sense Voltage

ON/OFF Pin Current

DS100034-7

DS100034-9

DS100034-8

Supply Current

DS100034-10

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Typical Performance Characteristics Unless otherwise specified: T

is tied to 1.5V. (Continued)

= 25˚C, CIN= 1 µF, ON/OFF pin

A

ON/OFF Input Resistance

Gate-Ground Saturation

DS100034-11

Gate Current

DS100034-34

Line Regulation

DS100034-13

Load Regulation

DS100034-15

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DS100034-14

Leakage Current

DS100034-35