AP1539

18V 4A 300KHz BUCK CONVERTER

AP1539 Rev. 2

3 of 12

FEBRUARY 2009

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Block Diagram

Oscillation

Circuit

Reference Voltage

Source with Soft Start

PWM-Switched

Control Circuit

+

-

Vss

V

EN

EN

90uA

OCSET

FB

Vcc

Thermal

Shutdown

Output

Absolute Maximum Ratings

Symbol

Parameter

Rating

Unit

ESD HBM

Human Body Model ESD Protection

7

KV

ESD MM

Machine Model ESD Protection

450

V

V

Feedback Pin Voltage

V

EN Pin Voltage

V

Switch Pin Voltage

V

Power Dissipation

Internally limited

mW

Operating Junction Temperature Range

-40 to +125

Storage Temperature Range

-65 to +150

Caution: The absolute maximum ratings are rated values exceeding which the product could suffer physical damage.

These values must therefore not be exceeded under any conditions.

Recommended Operating Conditions

Symbol

Parameter

Min

Max

Unit

Input Voltage (Note 4)

3.6

18

V

Output Current

0

4

A

Operating Ambient Temperature

20

+85

Notes:

4. For the operations in low input voltage, AP1539 can tolerate down to 3.6V but max output current loading will be less than 4A. For nominal

applications in such low input voltage range, especially lower than 4V, a higher ROCSET with larger heat sink is recommended.