SL5500S

Overview

The SL5500S is a high-voltage, low-power switching regulator controller manufactured by onsemi. Designed for offline flyback converter applications, it integrates a high-voltage startup circuit and a current-mode control architecture to ensure stable operation across wide input voltage ranges. The device features cycle-by-cycle current limiting and open-loop foldback protection to safeguard against overload conditions. It operates with an internal oscillator that supports fixed or variable frequency configurations, enabling efficient power conversion in compact designs while maintaining regulatory compliance for electromagnetic interference.

Feature Summary

• Integrates a high-voltage startup circuit for reliable initialization from AC mains
• Provides current-mode control for improved line and load regulation
• Includes built-in cycle-by-cycle current limiting for robust fault protection
• Supports open-loop foldback to reduce output current during short-circuit events

Applications

• Offline flyback power supplies for consumer electronics
• Adapter and charger designs for mobile devices
• Low-power industrial control systems requiring isolated DC-DC conversion
• Battery chargers for portable equipment

Procurement Notes

Verify the exact part marking and date code upon receipt to confirm authenticity. Cross-reference the orderable part number with onsemi’s official documentation to ensure compatibility with your design specifications. Check for any recent revisions or obsolescence notices directly from the manufacturer before finalizing procurement decisions.

Selection Notes

Choose this component when designing flyback converters that require integrated high-voltage startup and current-mode control without external bias winding complexity. Evaluate thermal performance and PCB layout constraints to maximize efficiency. Confirm that the operating frequency range aligns with transformer design requirements and EMI filtering capabilities of the target application.

Part Context

The SL5500S belongs to onsemi’s family of offline switcher controllers optimized for cost-sensitive, high-volume applications. It complements other similar controllers like the NCP1200 series but offers distinct integration levels suited for specific power ranges. Its design focuses on reducing external component count while maintaining reliability in standard flyback topologies commonly used in global power adapter markets.

Replacement Considerations

Direct substitutes may include the NCP1200 series variants if pinout and electrical characteristics match. Verify functional equivalence through detailed datasheet comparison, particularly regarding startup current, switching frequency limits, and protection thresholds. Ensure mechanical footprint compatibility if board space is constrained.