140V, 400mA step-down converter with only 12µA quiescent current

Linear Technology has announced the LTC7138, a 140V input-capable high efficiency buck converter that delivers up to 400mA of continuous output current. It operates from an input voltage range of 4V to 140V, making it ideal for a wide range of telecom, industrial, avionic and automotive applications.

The LTC7138 utilises a programmable hysteretic mode design to optimise efficiency over a broad range of output currents. It utilises an internal 1.8 Ohm power MOSFET for robust, high efficiency operation. A user-programmable output current limit can set output current from 100mA to 400mA as required by the particular application. The LTC7138 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 LTC7138’s thermally enhanced MSOP offers additional pin spacing required for high voltage inputs. The combination of its MSOP and only four tiny externals provides a highly compact solution footprint for a wide array of applications.

The LTC7138 draws only 12µA at no load while maintaining output voltage regulation, making it ideal for always-on battery-powered applications. Due to the inherent stability of the converter, no external compensation is required thereby simplifying design and minimising the solution footprint. Additionally, features include a precise 0.8V ±1% feedback voltage reference, 100% duty cycle dropout operation and, internal or external soft-start, and a feedback comparator output which enables multiple LTC7138s to be connected in parallel for higher current applications.

Pricing for the LTC7138EMSE, starts at $3.80 each. An industrial temperature version, the LTC7138IMSE, is guaranteed to operate from a -40°C to 125°C operating junction temperature and is priced at $4.18 each. Furthermore, an automotive temperature version, the LTC7138HMSE, is specified to operate from a -40°C to 150°C operating junction temperature and is priced at $4.43 each. Finally, a high reliability version, the LTC7138MPMSE, is tested and guaranteed to operate from a -55°C to 150°C operating junction temperature and is priced at $11.29 each. All pricing is for 1,000-piece quantities and all versions are available from stock.