140V buck converter delivers only 12µA quiescent current

The converter further utilises a programmable hysteretic-mode design to optimize efficiency over a broad range of output currents. The device delivers efficiencies as high as 88% and requires only 12µA of quiescent current, maximizing battery run time. As required by the application, a user-programmable output current limit can be set from 20mA to 250mA. Further to this, the device 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 offers the additional pin spacing required for high voltage inputs. The combination of its MSOP package and only four tiny externals provide a highly compact solution footprint for a wide range of applications.

Incorporating internal high side and synchronous power switches, which draw only 12µA at no load while maintaining output voltage regulation, make the device suitable for always on battery-powered applications. Due to the inherent stability of the converter, no external compensation is required, thereby simplifying design and minimizing the solution footprint. The converter further boasts a feedback comparator output, which enables multiple LTC3638s to be connected in parallel for higher current applications. Additional features include a precise 0.8V ±1% feedback voltage reference and an internal or external soft-start.

The TC3638EMSE is priced at $3.65 each, with the LTC3638IMSE industrial temperature version priced starting at $4.02 each. The industrial version guarantees over a -40°C to 125°C operating junction temperature. An automotive temperature version, the LTC3638HMSE, is guaranteed from -40°C to 150°C operating junction temperature and is priced starting at $4.27 each. Finally, a high reliability military plastic version, the LTC3638MPMSE, is tested and guaranteed to meet spectacular over a -55°C to 150°C operating junction temperature and is priced starting at $10.84 each. All pricing is in 1,000-piece quantities and all versions are available from stock.