LM5021 Datasheet | National Semiconductor

Description The LM5021 off-line pulse width modulation (PWM) controller contains all of the features needed to implement highly efficient off-line single-ended flyback and forward power converters using current-mode control. The LM5021 features include an ultra-low (25 µA) start-up current, which minimizes power losses in the high voltage start-up network. A skip cycle mode reduces power consumption with light loads for energy conserving applications (ENERGY STAR ® , CECP, etc.). Additional features include under-voltage lockout, cycle-by-cycle current limit, hiccup mode overload protection, slope pensation, soft-start and oscillator synchronization capability. This high performance 8-pin IC has total propagation delays less than 100n S and a 1MHz capable oscillator that is programmed with a single resistor. Features n n n n n n n n n n n n n n n Ultra Low Start-up Current (25 µA maximum) Current Mode Control Skip Cycle Mode for Low Standby Power Single Resistor Programmable Oscillator Synchronizable Oscillator Adjustable Soft-start Integrated 0.7A Peak Gate Driver Direct Opto-Coupler Interface Maximum Duty Cycle Limiting (80% for LM5021-1 or 50% for LM5021-2) Slope pensation for (LM5021-1 Only) Under Voltage Lockout (UVLO) with Hysteresis Cycle-by-Cycle Over-Current Protection Hiccup Mode for Continuous Overload Protection Leading Edge Blanking of Current Sense Signal Packages: MSOP-8 or MDIP-8 Simplified Application Diagram © 2005 National Semiconductor Corporation DS201442 .national. Connection Diagram Top View .. MSOP-8 and MDIP-8 Ordering Information Order Number LM5021MM-1 LM5021MMX-1 LM5021NA-1 LM5021MM-2 LM5021MMX-2 LM5021NA-2 Description 80% Duty Cycle Limit 80% Duty Cycle Limit 80% Duty Cycle Limit 50% Duty Cycle Limit 50% Duty Cycle Limit 50% Duty Cycle Limit Package Type MSOP-8 MSOP-8 MDIP-8 MSOP-8 MSOP-8 MDIP-8 Supplied As Available Soon Available Soon 40 Units per Rail Available Soon Available Soon 40 Units per...