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.