If Military/Aerospace specified devices are required,

please contact the National Semiconductor Sales Office/

Distributors for availability and specifications.

V

7.5V

SW pin: Voltage to GND

21V

FB pin: Voltage to GND

7V

V

SD,T/F pins: Voltage to GND

7.5V

FET-T, FET-F: Voltage to GND

6V

Continuous Power Dissipation (Note 3) Internally Limited

Junction Temperature (T

J-MAX )

150˚C

Storage Temperature Range

-65˚C to +150

Maximum Lead Temperature

(Soldering)

(Note 4)

ESD Rating(Note 5)

Human Body Model

2.0kV

Input Voltage Range

2.7V to 5.5V

SW Voltage Max. (Note 6)

20V

Junction Temperature (T

Range

-40˚C to +110˚C

Ambient Temperature (T

Range (Note 7)

-40˚C to +85˚C

Thermal Properties

Junction-to-Ambient Thermal

Resistance (

θ

Package (Note 8)

37.3˚C/W

ate ESD precautions. Failure to observe proper ESD handling techniques can result in damage to the device.

Limits in standard typeface are for T

(-40˚C

≤ T

J

≤ +110˚C). Unless otherwise noted, specifications apply to the LM3551 and LM3552 Typical Application Circuit (pg.

1) with: V

Symbol

Parameter

Conditions

Min

Typ

Max

Units

I

Q

Quiescent Current

FB = V

1.47

2.0

mA

I

SD

Shutdown Current

V(SD) = V

IN

LM3551

2.55

5.0

µA

V(EN) = 0V

LM3552

0.1

2.3

I

CL(Note 11)

Switch Current Limit

V

2.1

A

V

FB

Feedback Voltage

1.2285

1.265

1.2915

V

I

FB(Note 13)

Feedback Pin Bias Current

50

nA

g

m

Error Amp

Transconductance

∆I = 5µA

135

µmho

A

V

Error Amp Voltage Gain

135

V/V

D

MAX

Maximum Duty Cycle

92.5

%

f

sw

Switching Frequency

0.9

1.25

1.6

MHz

I

SDPIN

Shutdown Pin Current

(LM3551)

V

3.0

6

µA

I

ENPIN

Enable Pin Current

(LM3552)

V

3.0

6

µA

I

T/FPIN

T/F Pin Current

V

26

nA

V

22

I

L-SW

SW Pin Leakage Current

V

0.07

8

µA

R

DSON-SW

SW Pin R

DSON

I

0.165

Ω

I

L-T

FET-T Leakage Current

0.1

µA

R

DSON-T

FET-T R

DSON

0.98

Ω

I

L-F

FET-F Leakage Current

0.1

µA

R

DSON-F

FET-F R

DSON

0.36

Ω

Th

SD/EN

Shutdown/Enable Pin

Threshold

Output High

1.2

V

Output Low

0.3

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