Date: 15th Jun 2011
ICs for designing MP grade sync rectified
isolated forward converter
Linear Technology has announced the high reliability (MP-grade)
version of its three power ICs LT1952/-1, LTC3900 and LT4430
to design 95% efficient sync rectified isolated forward
converter type power supply to operate in high temp range
where the junction temp range of these devices is rated
at -55°C to 125°C.
The LT1952/-1 is a single switch forward controller with
active transformer reset that provides timing signals to
the secondary-side LTC3900 synchronous rectifier driver.
The LT4430 is a secondary-side optodriver with a precision
reference voltage that completes the tightly regulated isolated
forward converter circuit. The LTC3900 and LT4430 are specified
to a maximum operating junction temperature of 150°C.
This type of forward converter design is suggested for for
12V, 24V and 48V nominal input voltages, commonly found
in telecom, datacom, industrial and military/aerospace applications.
The LT1952/-1 includes all of the features necessary to
implement an active clamp transformer reset, enabling higher
efficiencies and greater power densities compared to conventional
catch winding or resonant reset techniques. Two control
outputs are provided: the main power switch control and
the active clamp switch control. Additional features include
a fixed programmable operating frequency from 100kHz to
500kHz, synchronizable up to 750kHz, selectable maximum
duty cycle, adjustable synchronous timing delay, undervoltage
lockout, a low 100mV current sense threshold, leading edge
blanking and programmable soft start.
Price ,Package and Availability: The LT1952/-1MP
is available in a SSOP-16 package and 1,000-piece pricing
starts at $9.35 each. The LTC3900MP is available in an SO-8
package and 1,000-piece pricing starts at $7.00 each. The
LT4430MP is available in a TSOT-23 package and 1,000-piece
pricing starts at $5.12 each.
For more information, visit www.linear.com/product/LT1952
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