NCP1251ASN65T1G

AC DC Converters, Offline Switchers Overview

The NCP1251ASN65T1G is a high-performance PWM controller for offline power supplies, housed in a compact TSOP-6 package. It operates with a fixed switching frequency of 65 kHz and supports a supply voltage range of 8.8 V to 28 V. The device utilizes peak current mode control with an internal oscillator and features automatic frequency foldback down to 26 kHz during light load conditions. Key electrical parameters include a maximum duty cycle of 80% and output drive currents of 500 mA and 300 mA. It integrates comprehensive protection mechanisms including over-power, over-voltage, and short-circuit protection.

AC DC Converters, Offline Switchers Feature Summary

• Integrates proprietary over-power protection allowing full power utilization without impacting standby performance via two external resistors.
• Features combined latched over-voltage protection and auto-recovery OVP monitoring the Vcc line for enhanced fault tolerance.
• Includes timer-based short-circuit protection that ensures precise trip points independent of transformer winding coupling.
• Automatically reduces switching frequency to minimize noise and improve efficiency under light load or no-load conditions.

AC DC Converters, Offline Switchers Applications

• Offline flyback converters for AC-DC power adapters
• Low standby power consumer electronics power supplies
• Battery chargers requiring efficient light-load operation

AC DC Converters, Offline Switchers Procurement Notes

Verify the specific suffix ASN65 against the manufacturer's latest datasheet to confirm the 65 kHz frequency variant. Ensure the TSOP-6 package dimensions match your PCB footprint requirements. Check for any recent Product Change Notifications regarding material declarations or assembly changes. Confirm availability status as some listings indicate end-of-life status for this specific part number.

AC DC Converters, Offline Switchers Selection Notes

Select this component when designing flyback converters requiring strict EMI limits due to its spread-spectrum jittering capability. It is suitable for applications demanding high efficiency at light loads through automatic frequency foldback. Consider the integrated protection features if minimizing external components and ensuring robust fault handling are priorities. Verify that the 8.8 V to 28 V supply range aligns with your auxiliary winding design.

AC DC Converters, Offline Switchers Part Context

This part belongs to the NCP1251 family of current-mode PWM controllers designed for cost-effective and high-density offline power supplies. The family includes variants with different switching frequencies, such as the 100 kHz version (NCP1251ASN100T1G). These controllers share common architectural features like peak current mode control and integrated protection schemes, tailored for various regulatory compliance needs.

AC DC Converters, Offline Switchers Replacement Considerations

The NCP1251CSN65T1G is a verified alternative within the same series offering similar functionality. The NCP1251ASN100T1G serves as a substitute if a higher 100 kHz switching frequency is required instead of 65 kHz. Ensure pin compatibility and thermal characteristics are reviewed before substitution.