FEATURES

? 40 V Input Voltage Surge

? 36 V Steady State Operation

? Up to 3.5 A output current

? Output Voltage up to 12 V

? 125 kHz Switching Frequency Eases EMI Design

? 91% Efficiency (VOUT = 5 V@2.4 A at VIN = 12 V)

? Stable with Low-ESR Ceramic Capacitors to Allow

Low-Profile Designs

? Integrated Over Voltage Protection

? Excellent EMI Performance

? Patented ActiveCC Sensorless Constant Current

Control Improves Efficiency and Lowers Cost.

? Resistor Programmable

? Current Limit from 1.5 A to 4.0 A

? Patented Cable Compensation from 0 to 0.25 Ω

? ±7.5% CC Accuracy

? Compensation of Input /Output Voltage Change

? Temperature Compensation

? Independent of inductance and Inductor DCR

? 2% Feedback Voltage Accuracy

? Advanced Feature Set

? Integrated Soft Start

? Thermal Shutdown

? Secondary Cycle-by-Cycle Current Limit

? Protection Against Shorted ISET Pin

? SOP-8EP Package

? QSPICE? Model Available

APPLICATIONS

? Car Charger/ Adaptor

? 24V Industrial Power Supplies

? Rechargeable Portable Device

? CV/CC Regulation DC/DC Converter

GENERAL DESCRIPTION

ACT4533A/B is a wide input voltage, high efficiency

ActiveCC step-down DC/DC converter that operates

in either CV (Constant Output Voltage) mode or

CC (Constant Output Current) mode. ACT4533A/B

provides up to 3.5 A output current at 125 kHz

switching frequency.

ActiveCC is a patented control scheme to achieve highaccuracy

sensorless constant current control. ActiveCC

eliminates the expensive, high accuracy current sense

resistor, making it ideal for CLA applications.

ACT4533A/B integrates adaptive gate drive to

achieve excellent EMI performance passing

EN55022 Class B EMC standard without adding

additional EMI components while maintaining high

conversion efficiency.

Protection features include cycle-by-cycle current limit,

thermal shutdown, and frequency foldback at short circuit.

The devices are available in a SOP-8EP package

and require very few external devices for operation.

The only difference between ACT4533A and

ACT4533B is that Pin 7 provides OVP for ACT4533A

and EN/OVP for ACT4533B.

The ACT4533A/B provides a basic building block for industrial

applications which require a nominal 24V input

voltage bucked down to an intermediate level.