Synchronous Buck Converters With Input And Output Current Limiting And Monitoring

The new LTC3626 Milpitas, California (United States) July 19, 2012 the new LTC3626 is a high efficiency of 3MHz-Synchron-Abwartsregler with internal input and output current limiting and monitoring. The chip in the 3mm x 4mm tiny QFN package is based on a unique current-mode architecture with constant switching frequency / time controlled and can deliver a continuous output currents of up to 2.5 for output voltages up to down to 0,6V. The current-mode architecture provides an excellent control for fast input and load changes also with high ratios of backward. Its wide input voltage range of 3, 6V to 20V is the LTC3626 for a wide range of operating voltage sources, including multiple cells lithium-ion batteries and 5V to 18V-Intermediate-Bus-Systeme. The limitation of the medium input and output streams is pin programmable, thus the chip ideal for applications such as power over USB.

The high, programmable in the range of 500 kHz to 3 MHz and synchronizable switching frequency allows the use of tiny, low-cost capacitors and inductors. The LTC3626 contains the switches with an RDS(on) of just 115mOhm or 70mOhm and achieved efficiencies up to 95%. Its unique loop architecture allows key ratios down to 5% at switching frequencies up to 2,25MHz; the chip is an ideal solution for step-down regulator applications with wide input / output voltage ratio, for example, 12VIN to 1,2VOUT. To maximize the effectiveness of the chip at low load in the burst works fashion. By the extremely low no-load quiescent current of only 300A chip suitable for applications that require a long battery life. In applications, where it’s as low switching noise, the LTC3626 in a forced continuous mode can be operated, which reduces switching noise and mitigates interference radiation problems. An internal temperature monitor provides a temperature proportional voltage for the programmable temperature limit. The chip also has a “power Good “signal output to the output voltage monitoring, supports output voltage tracking and is short-circuit protected.