NCP1377BPG

AC DC Converters, Offline Switchers Overview

The NCP1377BPG is a PWM current-mode controller designed for free-running quasi-resonant flyback converters. It integrates a true current-mode modulator and demagnetization detector to ensure boundary or critical conduction mode operation with minimal drain voltage switching. The device features an internal 3.0µs timer that allows higher switching frequencies compared to the standard NCP1377, while maintaining compliance with CISPR-22 EMI limits through skip regulation. It includes fast overvoltage protection via auxiliary winding detection, which permanently latches off upon fault detection. The controller supports soft start and operates within a temperature range of -25°C to +125°C in a PDIP-7 package.

AC DC Converters, Offline Switchers Feature Summary

• Enables boundary or critical conduction mode operation for reduced switching losses
• Integrates fast overvoltage protection with permanent latch-off capability
• Features internal timing control to manage frequency and EMI emissions
• Supports burst mode operation at low peak currents to eliminate audible noise

AC DC Converters, Offline Switchers Applications

• Universal offline power supplies
• Flyback converter designs requiring quasi-resonant operation
• Adapters and chargers with strict EMI requirements
• Power supplies needing fast overvoltage protection

AC DC Converters, Offline Switchers Procurement Notes

Verify component authenticity through authorized onsemi distributors or certified partners. Confirm the specific suffix PG indicates the PDIP-7 through-hole package variant. Check for end-of-life status or last-time-buy notifications as availability may be restricted. Ensure storage conditions comply with moisture sensitivity levels if applicable. Request original manufacturer documentation to validate revision history and compliance certifications before integration into production designs.

AC DC Converters, Offline Switchers Selection Notes

Select this controller when designing flyback converters that require quasi-resonant operation with higher frequency capabilities than the standard NCP1377. The B version offers a shorter internal timer duration, allowing for increased switching frequencies while managing EMI. Consider the PDIP-7 package for through-hole assembly requirements. Evaluate the need for permanent latch-off overvoltage protection versus recovery modes available in other family members. Ensure the application benefits from the integrated demagnetization detection for simplified transformer design.

AC DC Converters, Offline Switchers Part Context

The NCP1377BPG belongs to the NCP1377 series of offline switching controllers from onsemi. This series is engineered for high-performance flyback applications, combining current-mode control with quasi-resonant valley switching. The B variant specifically modifies the internal timing characteristics to support higher operating frequencies compared to the base model. It serves as a key component in power management IC portfolios focused on efficiency and electromagnetic interference reduction in universal input power supplies.

AC DC Converters, Offline Switchers Replacement Considerations

The NCP1377PG is a direct pin-compatible alternative within the same series, differing primarily in internal timer duration and maximum switching frequency capabilities. Verify that the application can tolerate the lower frequency limit of the NCP1377PG if substituting. No other public confirmed substitute part numbers are identified in the provided documentation.