LM5021MM-2

AC DC Converters, Offline Switchers Overview

The LM5021MM-2 is an AC-DC current-mode PWM controller designed for offline single-ended flyback and forward power converters. It operates within an input voltage range of 8 V to 30 V, with a nominal rating of 15 V. The device features a maximum switching frequency of 560 kHz and utilizes a PDSO8 or MSOP-8 package with an 8-pin configuration. It supports peak current control mode and functions reliably across an operating temperature range from -40°C to 125°C.

AC DC Converters, Offline Switchers Feature Summary

• Integrates an ultra-low startup current capability to minimize high-voltage start-up network losses
• Includes skip cycle mode operation to reduce power consumption during light load conditions
• Provides adjustable soft-start functionality alongside undervoltage lockout with hysteresis
• Features integrated hiccup mode overload protection and cycle-by-cycle overcurrent limiting

AC DC Converters, Offline Switchers Applications

• DCM/CCM flyback converters
• Industrial power conversion systems
• SMPS for smart meters and audio amplifiers
• Building automation and white goods SMPS
• Isolated telecom power supplies

AC DC Converters, Offline Switchers Procurement Notes

Verify the specific suffix designation to confirm the maximum duty cycle limit, as the LM5021-2 variant differs from the LM5021-1. Ensure the ordering part number matches the required package type, such as VSSOP-8 or PDIP-8. Confirm that the component meets the necessary automotive or industrial temperature ratings if deployed in harsh environments. Cross-reference the manufacturer datasheet revision date to ensure compatibility with current design specifications.

AC DC Converters, Offline Switchers Selection Notes

Select this controller for applications requiring current-mode control with low standby power consumption. The LM5021-2 variant is suitable where a 50% maximum duty cycle is sufficient, distinguishing it from the 80% duty cycle version. Consider the integrated gate driver and slope compensation capabilities when designing the transformer and feedback loop. Evaluate the oscillator synchronization feature if multiple converters operate in close proximity to prevent interference.

AC DC Converters, Offline Switchers Part Context

The LM5021 belongs to a family of AC-DC current-mode PWM controllers manufactured by Texas Instruments, formerly National Semiconductor. This series is engineered for high-efficiency offline power conversion. The MM-2 suffix indicates a specific variant within the LM5021 lineup, characterized by its duty cycle limitations and package configuration. It serves as a core component in modern switch-mode power supply designs.

AC DC Converters, Offline Switchers Replacement Considerations

LM5021MM-1/NOPB

AC DC Converters, Offline Switchers FAQ

What is the maximum duty cycle for the LM5021MM-2?

The LM5021-2 variant has a maximum duty cycle limit of 50%, whereas the LM5021-1 variant allows up to 80%.

Does the LM5021 support oscillator synchronization?

Yes, the device includes a synchronizable oscillator that can be programmed with a single resistor and synchronized to an external clock.

How does the LM5021 handle overload conditions?

It employs a hiccup mode for continuous overload protection, which reduces average power dissipation during fault conditions.