Step down regulator targets automotive and telecom systems

The LT3641 has a 4 to 42V input voltage range with 55V transient capability and is designed for load dump and cold crank conditions. It utilises a dual channel design with a high input voltage nonsynchronous channel, which is said to deliver 1.3A of output current. The device also has a lower input voltage synchronous channel, which is capable of delivering up to 1.1A of continuous output current. Using a nominal 12V input and a 2MHz switching frequency, the LT3641 can deliver a 3.3V output at 600mA with 85% efficiency via its high voltage channel and a 1.8V output at 800mA with 90% secondary conversion efficiency via its lower voltage channel. Its integrated microprocessor supervisor functions support high reliability applications such as automotive electronic control units. The LT3641 includes one power on reset timer for each channel and one common watchdog timer. The reset and watchdog timeout periods are independently adjustable using external capacitors. The regulator's switching frequency is user programmable from 350kHz to 2.5MHz, which, according to Linear, enables designers to optimise efficiency while avoiding critical noise sensitive frequency bands. Capable of delivering output voltages down to 1.26V on its high voltage channel and down to 0.6V on its low voltage channel, the device is optimised to power the latest generation of microprocessors. Its low ripple Burst Mode operation is said to reduce quiescent current to 290µA with less than 15mVPK-PK of output ripple.