NCP1251BSN65T1G

AC DC Converters, Offline Switchers Overview

The NCP1251BSN65T1G is a highly integrated PWM controller designed for rugged, high-performance offline power supplies within a compact TSOP-6 package. It operates in peak current mode with a jittered switching frequency of 65 kHz and supports a supply voltage range up to 35 V. The device features automatic frequency foldback down to 26 kHz during light load conditions and enters skip-cycle mode as power decreases further. Integrated protections include proprietary over-power protection (OPP), combined over-voltage protection (OVP) on the same pin, and timer-based short-circuit protection.

AC DC Converters, Offline Switchers Feature Summary

• Implements fixed-frequency 65 kHz current-mode control with internal jittering to optimize electromagnetic interference performance.
• Provides automatic frequency foldback to 26 kHz and skip-cycle operation to enhance efficiency under light load conditions.
• Integrates proprietary over-power protection (OPP) allowing maximum power delivery without affecting standby performance via two external resistors.
• Combines over-voltage protection (OVP) and timer-based short-circuit protection on shared or dedicated pins for robust fault handling.

AC DC Converters, Offline Switchers Applications

• Offline flyback power converters
• Adapters and chargers requiring low standby power
• Consumer electronics power supplies
• Industrial equipment auxiliary power

AC DC Converters, Offline Switchers Procurement Notes

Verify the specific suffix 'BSN' against official datasheets to confirm the exact switching frequency variant and package tolerance. Ensure compatibility with the required flyback topology and input voltage ranges. Confirm that the TSOP-6 package dimensions meet the target PCB layout constraints. Check for RoHS compliance status if environmental regulations apply to the final assembly.

AC DC Converters, Offline Switchers Selection Notes

Select this component when a compact solution for offline flyback applications is required with integrated EMI reduction features. The built-in frequency jittering and foldback capabilities make it suitable for designs prioritizing efficiency across varying load conditions. Consider the dual-pin OVP functionality if optocoupler failure protection is a critical design requirement.

AC DC Converters, Offline Switchers Part Context

This part belongs to the NCP1251 series of current-mode PWM controllers from onsemi. It is an improved version based on the popular NCP1250 family, offering enhanced integration and reliability. The series is specifically engineered for cost-effective, high-density power supply designs where size and performance are balanced.

AC DC Converters, Offline Switchers Replacement Considerations

The NCP12510 series serves as a pin-compatible improvement over earlier models like the NCP1250. Verify electrical parameter alignment, particularly regarding supply voltage limits and switching frequency options, before substituting other variants within the broader NCP125x family.