100mA synchronous buck converter ready for always-on apps

Linear Technology recently rolled out a 150V input-capable synchronous buck converter that delivers up to 100mA of continuous output current. The LTC3639 buck converter operates from an input voltage range of 4.5V to 150V, eliminating the need for an external transient suspension device.

Linear's latest converter uses internal synchronous rectification and a programmable peak current-mode design to optimise efficiency over a broad range of output currents. It delivers efficiencies as high as 92 per cent and requires only 12?A of quiescent current, maximising battery run time and eliminating thermal issues. A user-programmable output current limit can set output current from 10mA to 100mA thereby minimising the need to oversise external components and protecting high impedance sources.

The LTC3639 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 VIN. Its thermally enhanced MSOP package offers the additional pin spacing required for high voltage inputs. The combination of its MSOP package with only three tiny externals provides a highly compact solution footprint for a broad range of applications.

Drawing only 12?A at no load while maintaining output voltage regulation, the converter's internal high side and synchronous power switches make it ideal for always-on battery-powered applications. Due to the inherent stability of the converter, no external compensation is required, simplifying the design and minimising the solution footprint. Additional features include a precise 0.8V ±1 per cent feedback voltage reference, internal or external soft-start and a feedback comparator output which enables multiple LTC3639s to be connected in parallel for higher current applications.

Pricing for the LTC3639EMSE starts at $3.65 each. An industrial temperature grade version, the LTC3639IMSE is guaranteed to operate from -40°C to 125°C operating junction temperature, priced at $4.02 each. An automotive temperature grade, the LTC3639HMSE is guaranteed to operate over a -40°C to 150°C operating junction temperature range priced at $4.27 each. Finally, a high reliability military plastic version, the LTC3639MPMSE, is tested and guaranteed to operate from -55°C to 150°C operating junction temperature, priced at $10.84 each. All pricing is in 1,000 piece quantities and all versions are available from stock.

Further information regarding Linear Technology's LTC3639 can be found here .