Linear Technology Corporation announces the LT3641, a dual channel, current mode step-down switching regulator with a power-on reset and watchdog timer. Its 4V to 42V input voltage range with 55V transient capability makes it ideal for load dump and cold crank conditions commonly found in automotive applications which require constant output regulation even with input transients as high as 55V. The LT3641 uses a unique dual channel design with a high input voltage (4VIN to 42VIN, 55VIN transient capability) nonsynchronous channel, which delivers 1.3A of output current combined with a lower input voltage (2.5VIN to 5.5VIN) synchronous channel, delivering up to 1.1A of continuous output current. Although the part allows separate inputs for each channel, most applications will use the output of the high voltage channel to power the lower voltage channel, offering dual outputs while optimizing efficiency and switching frequency. For example, 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.