No-Opto flyback regulator delivers up to 5W at 100V

Linear Technology has announced the H-grade version of the LT8303, a monolithic flyback regulator with guaranteed operation for junction temperatures ranging from –40°C to 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.

According to the company, the device is suitable for a range of telecom, datacom, automotive, industrial, medical and military applications.

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 high level of integration and the use of low ripple Burst Mode operation is said to result in a 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 device is available in a small SOT-23 package.

Author
Peggy Lee