Monolithic flyback regulator guarantees operation for junction temperatures up to 150C

Linear Technology has announced the H-grade version of the LT8303, a monolithic flyback regulator with guaranteed operation for junction temperatures as high as 150C. By sampling the isolated output voltage directly from the primary-side flyback waveform, the part requires no opto-isolator or third winding for regulation. The device operates over a 5.5V to 100V input voltage range, has a 0.45A/150V integrated DMOS power switch and delivers up to 5W of output power, making it well suited for a wide range of telecom, datacom, automotive, industrial, medical and defence applications. The output voltage is set with only one external resistor and the transformer turns ratio. Several off-the-shelf transformers, identified in the data sheet, can be used for numerous applications. The LT8303 operates in boundary mode, which is a variable frequency current mode control switching scheme, typically resulting in ±1% output voltage load and line regulation. Boundary mode enables the use of a smaller transformer compared to equivalent continuous conduction mode designs. The high level of integration and the use of low ripple Burst Mode operation result in a simple to use, low component count and high efficiency application solution for isolated power delivery. It also features output overload and short-circuit protection, 70µA no load operating quiescent current, internal loop compensation along with an accurate enable and undervoltage lockout with hysteresis. The device operates over a –40C to 150C junction temperature range and is available in a small SOT-23 package.