Linear Introduces 36V Monolithic 1A Push/Pull DC/DC Transformer Driver

Programmable Duty Cycle Control Feature

September 23, 2014 – Linear Technology Korea (CEO Hong Sa-kwak, www.linear.com) announced the introduction of the LT3999, a monolithic push/pull isolated DC/DC transformer driver featuring two 1A current-limited power switches. The LT3999 operates over an input voltage range of 2.7V to 36V and can generate a wide range of output voltages targeting power levels up to 15W. This product is suitable for automotive, industrial, medical, and military applications.

The transformer's programmable duty cycle and turns ratio set the output voltage. Multiple transformer products presented in the datasheet are immediately available and simplify the design process. The switching frequency can be adjusted from 50kHz to 1MHz and can be synchronized to an external clock. The LT3999 input operating voltage range is set with precise undervoltage and overvoltage lockout. The supply current reduces to less than 1μA during shutdown. A user-defined RC time constant provides soft-start performance that can be controlled by limiting inrush current at startup, and an onboard cross-conduction protection circuit enhances reliability.

The LT3999 is available in MSOP-10 and 3mm × 3mm DFN-10 packages with enhanced thermal performance. The LT3999 E-grade and I-grade versions operate over a junction temperature range of –40°C to 125°C. The LT3999 H-grade is guaranteed to operate at a junction temperature of –40°C to 150°C. The LT3999 MP-grade is guaranteed to operate at a junction temperature of –55°C to 150°C. Devices are available now, with E-grade pricing at $2.75 per unit in quantities of 1,000. For more information, see www.linear.com/product/LT3999.

Photo caption: Push Pull DC/DC Transformer Driver

Product Features: LT3999

• Wide VIN Range: 2.7V to 36V

• Dual 1A Switches

• Programmable Switching Frequency: 50kHz to 1MHz

• Synchronizable to External Clock up to 1MHz

• Duty Cycle Control for Output Voltage Regulation

• Low Noise Topology

• Programmable Input Overvoltage & Undervoltage Lockout

• Cross-Conduction Protection Circuit

• Extended & Industrial Grade: –40°C to 125°C Operating Junction Temperature

• Automotive Temperature Grade: –40°C to 150°C Operating Junction Temperature

• Military Temperature Grade: –55°C to 150°C Operating Junction Temperature