High-reliability version for no-opto isolated monolithic flyback regulator

May 05, 2011 // By Christoph Hammerschmidt
Linear Technology has announced a high reliability (MP-grade) version of the LT3511, a high voltage isolated monolithic flyback regulator that operates over a -55 °C to 150 °C junction temperature range. The device simplifies the design of an isolated DC/DC converter since, Linear claims.

The LT3511 does not require an optocoupler, third winding or signal transformer for feedback, as the device's output voltage is sensed from the primary-side flyback signal. The LT3511 operates over a 4.5 V to 100 V input voltage range, has a 240 mA, 150 V onboard power switch and delivers up to 2.5 W, making it well suited for a wide variety of telecom, datacom, automotive, industrial and medical applications.

The LT3511 operates in a boundary mode, a current-mode control switching scheme, resulting in ±5% typical regulation over the full line, load and temperature range. Boundary mode, also known as critical conduction mode (CrCM), permits the use of a smaller transformer compared to equivalent continuous conduction mode designs. The output voltage is easily set by two external resistors and the transformer turns ratio. Several transformers identified in the data sheet can be used for numerous applications. Additional features include an onboard low dropout regulator for IC power, undervoltage lockout and output voltage temperature compensation. The high level of integration results in a simple, clean, tightly regulated solution for isolated power delivery.

The LT3511MPMS is available in a small MSOP-16 package with 4 pins removed for additional high voltage pin spacing. Pricing starts at $8.95 each in 1000-piece quantities. For more information, visit www.linear.com/product/LT3511.