Linear Technology Isolated Monolithic Flyback Regulator Delivers up to 15W
November 13, 2013 by John Day
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 LT8302 operates over a 2.8V to 42V input voltage range, has a 3.6A/65V power switch and delivers up to 15 Watts of output power.
The LT8302 operates in boundary mode, which is a variable frequency current-mode control switching scheme, typically resulting in +/-5% regulation over the full line, load and temperature range. Boundary mode enables 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 off-the-shelf transformers can be used for numerous applications. 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.
Additional features include output short circuit protection, a 380µA no load quiescent current with the output voltage in regulation, internal soft start and compensation, along with output diode temperature compensation.
The LT8302 is available in a small thermally enhanced SO-8 package. 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 and a military grade operates from –55°C to 150°C. Pricing starts at $3.47 each in 1000-piece quantities. For more information, visit www.linear.com/product/LT8302
Summary of Features: LT8302
- VIN Range from 2.8V to 42V
- Onboard 3.6A, 65V Integrated Power Switch
- No Transformer, Third Winding or Opto-Isolator Required for Feedback
- 380µA Quiescent Current
- Current-Mode Control
- Boundary-Mode Operation
- VOUT Set with Two External Resistors
- Off-the-Shelf Transformers
- Output Voltage Temperature Compensation
- Extended & Industrial Grades: –40°C to 125°C Operating Junction Temp
- Automotive Temp Grade: –40°C to 150°C Operating Junction Temp
- Military Temp Grade: –55°C to 150°C Operating Junction Temp