UNISONIC TECHNOLOGIES CO., LTD

P1785

Preliminary

LINEAR INTEGRATED CIRCUIT

www.unisonic.com.tw

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Copyright © 2011 Unisonic Technologies Co., Ltd

QW-R103-043.b

PWM CONTROL 2A

STEP-DOWN CONVERTER

DESCRIPTION

UTC P1785 consists of 2A step-down switching regulator

control which includes a reference voltage source, oscillation

circuit, error amplifier, internal PMOS and etc with PWM.

UTC P1785 can provide low-ripple power, high efficiency, and

excellent transient characteristics and an enable function, an over

current protect function and a short circuit protect function are

built inside, so the operation frequency will be reduced from

300KHz to 30KHz when OCP or SCP happens. And the PWM

control circuit can vary the duty ratio linearly from 100 down to

0%. This converter also includes an error amplifier circuit as well

as a soft-start circuit that prevents overshoot at startup. Also, to

minimum external component count an internal compensation

block is built in.

These ICs can work as step-down switching regulators with the

addition of an internal P-channel Power MOS, a coil, capacitors,

and a diode connected externally. They provide such outstanding

features: low current consumption. It is also suitable for the

operation via an AC adapter because this converter can

accommodate an input voltage up to 23V.

FEATURES

* Soft-start, Current Limit, Enable function

* Thermal Shutdown function

* Built-in internal SW P-channel MOS

* Input voltage: 3.6V to 23V.

* Duty ratio: 0% to 100% PWM control

* Oscillation frequency: 300KHz typ.

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ORDERING INFORMATION

Ordering Number

Lead Free

Halogen Free

Package

Packing

P1785L-S08-R

P1785G-S08-R

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Tape Reel

P1785L-S08-T

P1785G-S08-T

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Tube