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2.4MHz Step-Down DC/DC Converter Draws Only 85µA of Quiescent Current & Withstands 80V Transients

3rd September 2010

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Datasheet

Linear Technology has announced the LT3980, a 2A, 58VIN step-down switching regulator with Burst Mode operation to maintain quiescent current under 85µA. The LT3980 operates within a VIN range of 3.6V to 58V, with overvoltage lockout protection against transients as high as 80V, making the device ideal for load dump and cold-crank conditions commonly found in automotive applications. Its internal 3.4A switch can deliver up to 2A of continuous output current at voltages as low as 0.79V. The LT3980's Burst Mode operation provides ultralow quiescent current, well suited for applications such as automotive or telecom systems, which have always-on circuits and demand optimal battery life.

Switching frequency is user programmable from 100kHz to 2.4MHz, enabling the designer to maximize efficiency while avoiding critical noise-sensitive frequency bands. The combination of a 3mm x 4mm DFN-16 package (or thermally enhanced MSOP-16E) and high switching frequency keeps the LT3980's external inductor and capacitors small, providing a compact, thermally efficient footprint.

The LT3980 utilizes a high efficiency 3.4A, 200mOhm switch, with the necessary boost diode, oscillator, control and logic circuitry integrated into a single chip. Its catch diode current sense (DA pin) protects the circuit during input voltage transients even at high switching frequencies. Low ripple Burst Mode operation maintains high efficiency at low output currents while keeping output ripple below 15mVPK-PK. Special design techniques used in the LT3980 enable high efficiency over a wide input voltage range, and the device's current mode topology enables fast transient response and excellent loop stability. Other features include external synchronization (from 250kHz to 2MHz), a power good flag and soft-start capability.