High Voltage, Low Quiescent Current Synchronous Step-Down dc/dc Controller Operates from -55 to 125C

ELECTRONICS:  Linear Technology Corp.’s new high reliability (MP) grade version of the LT3845, 4 to 60V input voltage range, low quiescent current synchronous step-down dc/dc controller. Its Burst Mode^® operation keeps quiescent current under 120 µA in no load standby conditions, useful for extending run time in battery-powered applications. The device’s powerful onboard N-channel MOSFET gate drivers provide output current up to 20A at efficiencies as high as 95 percent, making it ideal for 12 and 24V automotive systems, industrial controls, heavy equipment, avionics and military systems.The LT3845 can produce an output voltage from 1.23 to 36V. The switching frequency is programmable from 100 to 500 kHz or can be synchronized to an external clock up to 600kHz. Current mode control provides fast line and load transient response, as well as cycle-by-cycle overcurrent protection. The onboard regulator provides IC power directly from the input supply without the need for a separate bias voltage. Other features include short-circuit protection, adjustable soft-start, thermal shutdown and precision input undervoltage lockout. The LT3845 employs adaptive nonoverlap control, which maintains a constant dead time, preventing shoot-through switch currents, independent of the type, size or operating conditions of the external MOSFET switches.

The LT3845MP operates and is 100 percent tested over a junction temperature range of -55 to 125C, compared to the I grade version’s -40 to 125C operating temperature range. It is offered in 16-lead thermally enhanced TSSOP package. 1,000-piece price starts at $10.65 each.

- Edited by Liz Taurasi