Linear Technology announces the LT3685, a 2A, 38V step-down switching regulator with input transient protection up to 60V. The LT3685's 3.6V to 38V operating input voltage range and 60V transient protection make it ideal for load dump and cold-crank conditions found in automotive applications. Its 3A internal switch can deliver up to 2A of continuous output current at voltages as low as 0.79V. Switching frequency is user programmable from 200kHz to 2.4MHz, optimizing efficiency while avoiding critical noise-sensitive frequency bands. Its high switching frequency keeps the external capacitors and inductor small, and the 3mm x 3mm DFN-10 package (or thermally enhanced MSOP-10E) provides a very compact, thermally efficient footprint.

The LT3685 utilizes a high efficiency 3A, 0.25 Ohm switch, with the necessary boost diode, oscillator, control and logic circuitry integrated on-chip. Special design techniques and a new high voltage process enable high efficiency over a wide input voltage range while the LT3685's current mode topology enables fast transient response and excellent loop stability. Other features include external synchronization (from 250kHz to 2MHz), a power good flag and soft-start capability. The LT3685EDD and LT3685EMSE are priced starting at $3.05 each and $3.15 each, respectively, for 1,000-piece quantities. The LT3685IDD and LT3685IMSE, tested and guaranteed to operate from a -40°C to 125°C operating junction temperature, are priced at $3.66 and $3.78 each, respectively in 1,000-piece quantities.