NCP1251ASN100T1G

AC DC Converters, Offline Switchers Overview

The NCP1251ASN100T1G is a current-mode PWM controller for offline flyback power supplies, manufactured by onsemi. It operates within an 8.8V to 28V supply range and features a fixed 100 kHz switching frequency with jitter for EMI optimization. The device supports a maximum duty cycle of 84% and includes integrated protection mechanisms such as over-power protection (OPP), over-voltage protection (OVP), and timer-based short-circuit protection. It utilizes a TSOP-6 surface-mount package.

AC DC Converters, Offline Switchers Feature Summary

• Integrates over-power protection (OPP) allowing high power utilization without impacting standby performance via two external resistors.
• Features automatic frequency fold-back to 26 kHz during light loads and skip-cycle mode for efficiency optimization.
• Combines latched and auto-recovery over-voltage protection (OVP) on the Vcc line for robust fault handling.

AC DC Converters, Offline Switchers Applications

• Offline AC-DC converters
• Flyback power supply designs
• Chargers and adapters

AC DC Converters, Offline Switchers Procurement Notes

Verify component status carefully as this specific part number may be subject to end-of-life restrictions or limited availability. Confirm that the TSOP-6 package and 100 kHz frequency variant align with design requirements before finalizing procurement plans.

AC DC Converters, Offline Switchers Selection Notes

Select this model when a compact TSOP-6 footprint is required for offline applications. The 100 kHz frequency setting suits designs prioritizing higher power density over lower EMI compared to the 65 kHz variant. Ensure compatibility with peak current mode control architectures.

AC DC Converters, Offline Switchers Part Context

This component belongs to the NCP1251 series of highly integrated PWM controllers designed for small form-factor offline power supplies. It shares architectural similarities with other variants in the family but differs in switching frequency configuration and specific pinout implementations.

AC DC Converters, Offline Switchers Replacement Considerations

NCP1251BSN100T1G

AC DC Converters, Offline Switchers FAQ

How does the NCP1251ASN100T1G handle light load conditions?

It automatically folds back the switching frequency to a minimum of 26 kHz and enters skip-cycle mode while limiting peak current to improve efficiency.

What protection features are integrated into this controller?

It includes over-power protection (OPP), over-voltage protection (OVP) on the Vcc line, and a timer-based short-circuit protection mechanism.