Features • Voltage-Mode control • Line feed-forward PWM ramp • Internal 105V rated start-up bias regulator • Programmable line Under-Voltage Lockout (UVLO) with adjustable hysteresis • Versatile dual mode over-current protection • Programmable volt-second limiter • Programmable soft-start • Programmable synchronous rectifier soft-start and stop • Precise 500mV over-current comparator • Current sense leading edge blanking • Programmable oscillator with 1 MHz maximum frequency and synchronization capability • Precision 5V reference • Programmable time delays between outputs Description The LM5027 pulse-width modulation (PWM) controller contains all of the features necessary to implement power converters utilizing the Active Clamp / Reset technique. With the active clamp technique, higher efficiencies and greater power densities can be realized compared to conventional catch winding or RDC clamp / reset techniques. Three control outputs are provided: the main power switch control (OUTA), the active clamp switch control (OUTB), and secondary side synchronous rectifier control (OUTSR). The timing between the control outputs is adjustable with external resistors that program internal precision timers. This controller is designed for high-speed operation including an oscillator frequency range up to 1 MHz and total PWM propagation delays less than 50 ns. The LM5027 includes a high-voltage startup regulator with a maximum input voltage rating of 105V. Additional features include Line Under Voltage Lockout (UVLO), separate soft-start of main and synchronous rectifier outputs, a timer for hiccup mode current limiting, a precision reference, and thermal shutdown.

Also Recommended LM5025C Active Clamp Voltage Mode PWM Controller LM5026 Active Clamp Current Mode PWM Controller LM5034 Dual Interleaved Active Clamp Current Mode Controller LM3411 Feedback Control / Optocoupler Driver For Isolated Supplies MY BRIEFCASE                                       Click any "Briefcase" icon to add an item

Typical Application click for larger image	Block Diagram click for larger image
Typical Performance click for larger image

Datasheet

Title		Size	Date	Other Language
	LM5027 Voltage Mode Active Clamp Controller	542 Kbytes	25-Sep-09

Featured Application Notes

Title		Size	Date	Other Language
	AN-1976: Application Note 1976 LM5027 Evaluation Board	588 Kbytes	19-Aug-09

More Application Notes

Title		Size	Date	Other Language
	AN-1875: Application Note 1875 LM5073HE Evaluation Board With Active Bridge	230 Kbytes	2-Jul-08
	AN-1574: Application Note 1574 LM5073 Evaluation Board	464 Kbytes	24-Apr-07
	AN-1387: Application Note 1387 LM5026 Evaluation Board	721 Kbytes	7-Sep-05	中文
	AN-1696: Application Note 1696 Designing a Boost LED Driver Using the LM5022	286 Kbytes	22-Feb-08	中文
	AN-1314: Application Note 1314 LM5020 Evaluation Board	612 Kbytes	10-Feb-05
	AN-1605: Application Note 1605 LM5022 Boost LED Driver Evaluation Board	769 Kbytes	2-Oct-07
	AN-1557: Application Note 1557 LM5022 Evaluation Board	513 Kbytes	22-May-08	中文

Reliability Metrics

Part Number	Process	EFR Reject	EFR Sample Size	PPM	LTA Rejects	LTA Device Hours	FITS	MTTF (Hours)
LM5027MH	ABCD150XV1	0	3868	0	0	2595000	2	736338335
LM5027MHX	ABCD150XV1	0	3868	0	0	2595000	2	736338335

Note: The Early Failure Rates (EFR) were calculated as point estimate PPM based on rejects and sample size for EFR. The Long Term Failure Rates were calculated at 60% confidence using the Arrhenius equation at 0.7eV activation energy and derating the assumed stress temperature of 150°C to an application temperature of 55°C.

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