LT1376

The LT^® 1375/LT1376 are 500kHz monolithic buck mode switching regulators. A 1.5A switch is included on the die along with all the necessary oscillator, control and logic circuitry. High switching frequency allows a considerable reduction in the size of external components. The topologyis current mode for fast transient response and good loop stability. Both fixed output voltage and adjustable parts are available.

A special high speed bipolar process and new design techniques achieve high efficiency at high switching fre- quency. Efficiency is maintained over a wide output cur- rent range by using the output to bias the circuitry  and by utilizing a supply boost  capacitor to saturate the power switch. A shutdown signal will reduce supply current to 20µ A on both parts. The LT1375 can be externally syn- chronized from 550kHz to 1MHz with logic level inputs.

The LT1375/LT1376 fit into standard 8-pin PDIP and SO packages, as well as a fused lead 16-pin SO with much lower thermal resistance. Full cycle-by-cycle short-cir- cuit protection and thermal shutdown are provided. Standard surface mount external parts are used, includ- ing the inductor and capacitors.

For low input voltage applications with 3.3V output, see LT1507. This is a functionally identical part that can operate with input voltages between 4.5V and 12V.