H-grade flyback regulator packs 5W power in hi-temp

Article By : Linear Technology

The LT8303 from Linear Technology operates over a 5.5V to 100V input voltage range, offering 5W power in compact SOT-23 footprint.

Linear Technology has announced the H-grade version of the LT8303, a monolithic flyback regulator with guaranteed operation for junction temperatures of 150°C. 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 LT8303 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 military applications.

 

Figure 1: H-grade LT8303 isolated monolithic flyback regulator.
 

The output voltage is set with only one external resistor and the transformer turns ratio. 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 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.

Additional features include 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 LT8303H operates over a –40°C to 150°C junction temperature range and is available in a small SOT-23 package.