Micro-power 65V buck converters offer industry’s lowest quiescent current

May 03, 2016 // By Nick Flaherty
LM5165 DC/DC converter
Texas Instruments (TI) has launched two 65V, 150mA synchronous DC/DC buck converters with 10.5μA quiescent current for powering factory automation and automotive sensors requiring high efficiency.

The industrial-grade LM5165 and automotive-grade LM5165-Q1 micro-power step-down regulators feature a wide input voltage (VIN) range and dual control modes for optimizing efficiency and printed circuit board (PCB) area. The wide 3V to 65V operating range enables the regulators to handle the highest transients in industrial sensor and programmable logic controller (PLC) applications, as well as start-stop and load-dump conditions for 12V/24V lead-acid and emerging 48V lithium-ion automotive batteries. Integrated dual metal-oxide semiconductor field-effect transistors (MOSFETs) reduce PCB area, while a programmable current-limit scheme reduces inductor size. Both regulators operate at junction temperatures up to 150ºC for higher temperature environments. The LM5165-Q1 is AEC-Q100 qualified for automotive applications.

The 10.5μA standby IQ (operating with no load) enables 90-percent conversion efficiency at 1mA to 10mA loads to extend battery life in “always on” applications, while the 100-percent duty cycle enables low-dropout operation. A P-channel high-side MOSFET eliminates the bootstrap diode and capacitor.

A pulse frequency modulation (PFM) control mode enables the highest efficiency power supply design, while a constant on-time (COT) control mode provides higher output current and better electromagnetic interference (EMI) performance, and f ixed 3.3V and 5V options eliminate external feedback resistor dividers to lower bill of materials (BOM).

The parts are included in TI's WEBENCH Designer and Power Architect online tools enable end-to-end circuit design, simulation and optimization for footprint, price and efficiency, with the ability to download schematic and PCB layout files directly into computer-aided design (CAD) tools. Component libraries include more than 40,000 components from 120 manufacturers, and TI’s distribution partners update price and availability hourly. 

The regulators are available in volume now from TI and its authorized distributors. Packaged in a 10-pin, 3-mm-by-3-mm VSON, the industrial-grade LM5165 is priced at US$1.35 in 1,000-unit quantities and the automotive-grade LM5165-Q1 is priced at US$1.58. For more information, samples and an evaluation module, see  www.ti.com/lm5165-pr-eu.