Step down dc/dc converters deliver 90% efficiency

Linear Technology has announced two new step down switching regulators designed for automotive and industrial applications.

The 42V LT3975 can deliver 2.5A of continuous output current and requires only 2.7µA of quiescent current, while the 40V LT3976 can deliver up to 5A and requires only 3.3µA. Both devices offer a 4.2 to 40V input voltage range with internal 75mOhm switches that are said to deliver up to 90% efficiency. Optimised for automotive cold crank conditions, the devices maintain a minimum dropout voltage of 500mV when the input voltage drops below the programmed output voltage. Switching frequency is user programmable from 200kHz to 2MHz and synchronisable from 250kHz to 2MHz. Linear says that the combination of a 16 lead thermally enhanced MSOP package and high switching frequency keeps external inductors and capacitors small, providing a compact, thermally efficient footprint.