Industrial/automotive DC/DC supplies 0.25A, shuts down to 12 µA

February 10, 2014 // By Graham Prophet
LTC3638 is a 140V input-capable high efficiency buck converter that delivers up to 250mA of continuous output current. It operates from an input voltage range of 4V to 140V, for telecom, industrial, avionic and automotive applications.

The chip uses internal synchronous rectification and a programmable hysteretic-mode design to optimise efficiency over a broad range of output currents. It delivers efficiencies as high as 88% and requires 12 µA of quiescent current. A user-programmable output current limit can be set from 20 mA to 250 mA as required by the application. The LTC3638 can be programmed with fixed output voltages of 1.8V, 3.3V or 5V or a resistor divider can be used to program outputs from 0.8V to V IN. The LTC3638’s thermally enhanced skipped-lead MSOP package provides the additional pin spacing required for high voltage inputs. The combination of its MSOP package and four small external components provide a compact footprint.

High side and synchronous power switches contribute to 12 µA at no-load while maintaining output voltage regulation, for always-on battery-powered applications. No external compensation is required. Additional features include a precise 0.8V ±1% feedback voltage reference, internal or external soft-start and a feedback comparator output, which enables multiple LTC3638s to be connected in parallel for higher current applications.

Pricing for the LTC3638EMSE starts at $3.65 (1000). There are industrial temperature, automotive temperature and high reliability military plastic versions.

Linear Technology; www.linear.com/product/LTC3638