Linear Technology Launches Isolated Forward Converter IC with -55°C to 125°C Temperature Range

June 14, 2011 – Linear Technology Korea (CEO Hong Sa-kwak, www.linear.com ) announced the release of high-reliability (MP grade) versions of the LT1952/-1, LTC3900, and LT4430 products. These devices have undergone operational testing over an operating junction temperature range of -55°C to 125°C and, when used together, provide a high-efficiency (up to 95%) isolated synchronous rectifier forward converter solution. The LT1952/-1 is a single-switch forward controller with an active transformer reset function that provides timing signals to the secondary side LTC3900 synchronous rectifier driver. The LT4430 is a secondary side opto-driver with a precision reference voltage that completes a strictly regulated forward converter circuit. Both the LTC3900 and LT4430 offer operating junction temperatures up to 150°C. This type of forward converter design is suitable for 12V, 24V, and 48V nominal input voltages commonly used in communications, datacom, industrial, and military/aerospace applications.

The LT1952/-1 includes all the essential features for implementing an active clamp transformer reset, enabling it to provide superior efficiency and power density compared to conventional catch winding or resonant reset technologies. Additionally, two control outputs (main power switch control and active clamp switch control) are provided. Other features include a programmable fixed operating frequency in the range of 100 kHz to 500 kHz, a synchronizable frequency up to 750 kHz, a selectable maximum duty cycle, an adjustable synchronous timing delay, low voltage lockout, a low current sensing threshold of 100 mV, advanced blanking, and a programmable soft start.

The LT1952/-1MP is available in an SSOP-16 package, with prices starting at $9.35 per unit for 1,000 units. The LTC3900MP is available in an SO-8 package, with prices starting at $7.00 per unit for 1,000 units. The LT4430MP is available in a TSOT-23 package, with prices starting at $5.12 per unit for 1,000 units. For more information, please refer to www.linear.com/product/LT1952 , www.linear.com/product/LTC3900 , and www.linear.com/product/LT4430 .