560V No-Opto Flyback Regulator Delivers Up to 15 Watts in High Voltage Spacing TSSOP Package

Linear Technology LT8315

Linear Technology Corporation announces the LT8315, a high voltage monolithic flyback regulator that simplifies the design of an isolated DC/DC converter. By sampling the reflected isolated output voltage across the third winding on the power transformer, the part requires no opto-isolator or LT1431 for regulation. The LT8315 operates over an 18 V to 560 V input voltage range, has a 0.30 A/630 V integrated power switch and delivers up to 15 watts of output power, ideal for electric vehicles and battery stacks, as well as off line, automotive, industrial and medical applications.

Linear Technology - LT8315

Several off-the-shelf transformers identified in the data sheet can be used for numerous applications. The LT8315 operates in quasi-resonant boundary mode, which is a variable frequency current mode control switching scheme, resulting in better than ±1% 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.

Efficiency vs Load Current
Efficiency vs Load Current.

Additional features include output short-circuit protection, 70 μA no load operating quiescent current, accurate enable and undervoltage lockout with hysteresis, along with output diode temperature compensation.

The LT8315 is available in a TSSOP-20 package with four pins removed for high voltage spacing. Extended and industrial versions operate over a junction temperature range of –40 °C to 125 °C. A high temperature automotive grade operates from –40 °C to 150 °C. Pricing starts at $4.15 each in 1000-piece quantities.

Summary of Features: LT8315

  • VIN Range from 18 V to 560 V
  • Up to 15 Watts of Output Power
  • Onboard 0.30 A/630 V Power Switch
  • Off-the-Shelf Power Transformers
  • No Opto-Isolator or LT1431 Required for Voltage Feedback
  • 70 μA Quiescent Current
  • Quasi-Resonant Boundary Mode Operation
  • Accurate Input Enable & Undervoltage Lockout with Hysteresis
  • Output Diode Temperature Compensation
  • TSSOP Package with High Voltage Spacing
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