Absolute Maximum Ratings (Note 1)

If Military/Aerospace specified devices are required,

please contact the National Semiconductor Sales Office/

Distributors for availability and specifications.

V

IN

−0.3V to +7.5V

V

O_MAIN

−0.3V to +25V

V

SW

−0.3V to V

OUT

+0.3V

Main_FB, Main_RTN

−0.3V to +7.5V

MAIN_EN, PFM_EN &

SUB_EN(Note 2)

−0.3V to +7.5V

Continuous Power Dissipation

(Note 3)

Internally Limited

Maximum Junction Temperature

(T

+150˚C

Storage Temperature Range

−65˚C to +150˚C

Maximum Lead Temperature

(Soldering, 10 sec)

+265˚C

ESD Rating (Note 4)

Human Body Model:

Machine Model:

2.0 kV

200V

Operating Ratings

Input Voltage Range

2.7V to 5.5V

Junction Temperature (T

−40˚C to +125˚C

Ambient Temperature (T

(Note 3)

−40˚C to +85˚C

Thermal Properties

Junction-to-Ambient Thermal Resistance (

θ

55˚C/W

Leadless Lead frame Package (Note 5)

type apply over the full operating junction temperature range (−40˚C

≤ =T

J

≤ +125˚C). Unless otherwise noted: specifications

apply to the LM3520. V

Symbol

Parameter

Conditions

Min

Typ

Max

Units

Enable

Threshold

MAIN_EN = low

SUB_EN = low

0.3

V

MAIN_EN = high

SUB_EN = high

0.95

PFM_EN = low

0.3

V

PFM_EN = high

0.95

I

EN

Enable Pin Current

MAIN_EN = 3.6V (Note 10)

3

5

µA

SUB_EN = 3.6V (Note 10)

3

5

PFM_EN = 3.6V

3

5

I

Q

Quiescent Current, Device Not

Switching (PWM mode)

0.5

1.3

mA

Quiescent Current, Device Not

Switching (PFM mode)

0.25

0.45

Quiescent Current, Device

Switching

MAIN_FB = 0V or SUB_FB =

0V (open loop)

1.75

4.5

Power Off Current (Shutdown)

MAIN_EN = low

SUB_EN = low

PFM_EN = low

0.1

2

µA

V

FB

Feedback Voltage (MAIN_FB)

V

0.455

0.5

0.545

V

Feedback Voltage (SUB_FB)

V

1.18

1.23

1.28

I

B

FB Pin Leakage Current

MAIN_FB = 0.5V (Note 9)

10

nA

FB Pin Bias Current

SUB_FB = 1.0V (Note 9)

50

I

Current Limit

Switch Current Limit

V

0.518

0.7

0.917

A

R

Main_Switch R

I

0.5

Ω

PMOS Switch R

I

3

MAIN_RTN R

I

3

I

main_RTN_leakage

Main_RTN Leakage Current

V

0.2

µA

D

Limit

Duty Cycle Limit at PWM & PFM

V

90

%

F

SW

Switching Frequency

V

0.8

1.1

1.4

MHz

I

Leak

Switch Leakage Current

V

0.01

0.5

µA

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