Classification | PRIVATE

ACT4533A/B

Wide Input Sensorless CC/CV Step-Down DC/DC Converter

Data Sheet Rev. B, January 2025 | Subject to change without notice

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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 high-

accuracy 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 cir-

cuit. 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 in-

dustrial applications which require a nominal 24V input

voltage bucked down to an intermediate level.