Linear Tech Introduces 2.5uA Quiescent Current, 60V, 350mA(IOUT), 2.2MHz Step-Down DC-DC Converter

Linear Technology Corp. announced the LT3990, a 350mA, 60V ultralow quiescent current step-down switching regulator. Its Burst Mode® operation keeps quiescent current under 2.5µA in no load condition. The LT3990’s 4.3 to 60V input voltage range makes it well suited for automotive and industrial applications that need continuous output with ultralow power drain. Its internal 550mA switch can deliver up to 350mA of continuous output current at voltages as low as 1.21V. The LT3990’s Burst Mode operation provides ultralow quiescent current, well suited for automotive or industrial systems, which demand always-on operation and optimum battery life. Switching frequency is user programmable from 200kHz to 2.2MHz, enabling the designer to optimize efficiency while avoiding critical noise-sensitive frequency bands. The combination of its 10-lead 3 x 2mm DFN-10 (or MSOP) package and high switching frequency keeps external inductors and capacitors small, providing a very compact, thermally efficient footprint.

The LT3990 utilizes a high efficiency 550mA, 300mV switch, with the necessary boost and catch Schottky diodes, oscillator, control and logic circuitry integrated into a single die. Low ripple Burst Mode operation ensures high efficiency at low output currents while keeping output ripple below 5mVPK-PK. Special design techniques and a new high voltage process enable high efficiency over a wide input voltage range, and the LT3990’s current mode topology enables fast transient response and excellent loop stability. Other features include a power good flag soft-start capability and output short protection.

The LT3990EDDB is packaged in a 3mm x 2mm DFN-10, and the LT3990EMS is packaged in a MSOP-10, priced starting at $2.55 and $2.60 each, respectively for 1,000 piece quantities. The LT3990IDDB and LT3990IMS are tested and guaranteed to operate from a -40 to 125°C operating junction temperature and are priced at $2.83 and $2.89 each, respectively in 1,000 piece quantities.