Buck converter rated 60-V, 3-A, uses 2.7-uA of quiescent current

June 06, 2013 // By Paul Buckley
Linear Technology Corporation has introduced a 3 A, 60 V DC/DC step-down switching regulator, requiring 2.7 µA of quiescent current.

The LT3995’s 4.3 V to 60 V input voltage range makes it suitable for automotive, commercial vehicle, avionic and industrial applications. The device’s internal 4.7A switch can deliver up to 3A of continuous output current to voltages as low as 1.2V. The LT3995’s Burst Mode operation offers ultralow quiescent current, making it well suited for applications such as automotive or industrial systems, which demand always-on operation and optimum battery life.

The design of the LT3995 ensures a minimum dropout voltage of 500 mV even when the input voltage drops below the programmed output voltage, suitable for applications subjected to scenarios such as automotive cold-crank. Switching frequency is user-programmable from 200 kHz to 2 MHz, and synchronizable from 250 kHz to 2 MHz, enabling the designer to optimise efficiency while avoiding critical noise-sensitive frequency bands. The combination of its 16-lead thermally enhanced MSOP package and high switching frequency keeps external inductors and capacitors small, providing a highly compact, thermally efficient footprint.

The LT3995 utilises a high efficiency 4.7-A, 85-mOhm switch, with the boost diode, oscillator, control and logic circuitry integrated into a single die. Low ripple Burst Mode operation maintains high efficiency at low output currents while keeping output ripple below 15 mVP-P. Special design techniques and a new high voltage process enable efficiencies up to 90% over a wide input voltage range, while the LT3995’s current mode topology assures fast transient response and excellent loop stability. Other features include a power good flag, soft-start capability and thermal protection.
The LT3995EMSE is packaged in a thermally enhanced MSOP-16, priced starting at $3.55 (1,000) piece quantities. The LT3995IMSE is tested and guaranteed to operate from a -40°C to 125°C operating junction temperature and is priced at $3.91; the LT3995HMSE is tested and guaranteed to operate from a -40°C to 150°C operating junction temperature, priced at $4.16.
Linear Technology, www.linear.com/product/LT3995