NCP1256BSN65T1G

AC DC Converters, Offline Switchers Overview

The NCP1256BSN65T1G is a low-power offline PWM current-mode controller from onsemi, designed for cost-effective switching power supplies ranging from several watts to tens of watts. It operates in a TSOP-6 package with a supply voltage up to 30 V and features a fixed 65 kHz switching frequency with jitter for EMI reduction. The device utilizes peak current mode control and includes frequency foldback down to 26 kHz during light loads. Key electrical parameters include a maximum duty cycle of 80%, an operating temperature range of -40°C to +125°C, and a startup voltage range of 8.9 V to 28 V.

AC DC Converters, Offline Switchers Feature Summary

• Integrates adjustable over-power protection (OPP) that disables at low line voltages to limit output power without affecting standby performance.
• Features timer-based auto-restart short-circuit protection and dual-burst auto-restart modes for robust fault handling.
• Includes latching over-voltage protection (OVP) on the Vcc pin and a latch input for enhanced durability against OVP and OTP events.

AC DC Converters, Offline Switchers Applications

• AC-DC adapters for portable devices
• AC-DC adapters for computers
• AC-DC adapters for tablet devices
• Universal AC-DC adapters

AC DC Converters, Offline Switchers Procurement Notes

Verify the specific suffix 'BSN65' confirms the 65 kHz fixed frequency variant when ordering. Confirm the TSOP-6 package dimensions match the design footprint. Check RoHS compliance status via the manufacturer's official documentation before finalizing procurement specifications.

AC DC Converters, Offline Switchers Selection Notes

Select this component for designs requiring high efficiency at light loads due to its frequency foldback capability. Ensure the application benefits from the integrated OPP and short-circuit protections to simplify external circuitry. Verify that the 65 kHz frequency aligns with EMI requirements and transformer sizing constraints.

AC DC Converters, Offline Switchers Part Context

This part belongs to the NCP1256 series of current-mode controllers. It shares architectural similarities with other models in the family but is distinguished by its specific 65 kHz switching frequency configuration. The series is optimized for compact, high-performance offline power supplies using minimal external components.

AC DC Converters, Offline Switchers Replacement Considerations

Cross-reference with NCP1256ASN65T1G for alternative sourcing options within the same frequency family. Verify pinout compatibility and thermal characteristics against existing designs before substitution.

AC DC Converters, Offline Switchers FAQ

How does the controller manage efficiency under light load conditions?

The controller automatically folds back the switching frequency to a minimum of 26 kHz as secondary side power decreases. If power drops further, it enters skip-cycle mode while limiting peak current to enhance light-load efficiency.

What protection mechanisms are available for short circuits?

It provides timer-based auto-restart short-circuit protection and dual-burst auto-restart short-circuit protection, ensuring safe operation and reliable recovery after fault clearance.