NCP1377DR2G

AC DC Converters, Offline Switchers Overview

The NCP1377DR2G is a PWM current-mode controller designed for free-running quasi-resonant operation in flyback topologies. It integrates a true current-mode modulator and demagnetization detector to ensure boundary or critical conduction mode with minimal drain voltage switching. The device features an internal 8.0µs timer that prevents idle frequency from exceeding 150 kHz CISPR-22 EMI emission limits, alongside skip-cycle functionality for burst mode operation at low peak currents to eliminate audible noise. It includes transformer core reset detection via an auxiliary winding for fast overvoltage protection (OVP) with permanent latch-off capability.

AC DC Converters, Offline Switchers Feature Summary

• Integrates true current-mode modulation and demagnetization detection for efficient quasi-resonant switching
• Features internal timing control to limit idle frequency and prevent excessive electromagnetic interference emissions
• Provides fast overvoltage protection through dedicated auxiliary winding sensing with permanent latch-off

AC DC Converters, Offline Switchers Applications

• Offline power supplies requiring quasi-resonant operation
• Flyback converter designs with strict EMI constraints
• Power adapters where audible noise reduction is required

AC DC Converters, Offline Switchers Procurement Notes

Verify component authenticity as the NCP1377DR2G is listed as End-of-Life by onsemi. Confirm availability of alternative sources or substitute part numbers such as NCP1342AMDCCDR2G if production continuity is required. Ensure documentation matches the specific DR2G suffix for SOIC-8 packaging and RoHS compliance status before procurement.

AC DC Converters, Offline Switchers Selection Notes

Select this controller for applications requiring variable frequency operation to minimize switching losses and acoustic noise. The integrated skip-cycle function allows for efficient light-load performance without audible tones. Consider the 8.0µs timer constraint when designing for specific EMI filter requirements. Verify that the application does not require the higher frequency capabilities offered by the NCP1377B variant.

AC DC Converters, Offline Switchers Part Context

The NCP1377 series belongs to onsemi's offline controller portfolio, specifically targeting flyback converters. The NCP1377DR2G variant utilizes an SOIC-8 package and operates within a specified temperature range. It is distinct from the NCP1377B version, which features a shorter internal timer duration for higher frequency operation. This component is part of a broader family including NCP1337 and NCP1378 controllers.

AC DC Converters, Offline Switchers Replacement Considerations

Public confirmed substitute: NCP1342AMDCCDR2G.