Auto Electronics

Linear Technology step-down dc/dc converter offers low quiescent current

Linear Technology Corporation has introduced the LT3480, a 2 A, 38 V step-down switching regulator with input transient protection up to 60 V and quiescent current less than 70 µA in no-load standby conditions. A 3.6 V to 38 V input voltage range and 60 V transient protection suit the device for load dump and cold-crank conditions in automotive applications, the company said.

The LT3480 has a 3 A internal switch that can deliver up to 2 A of continuous output current to voltages as low as 0.79 V. Its burst mode operation offers low quiescent current for automotive applications that demand always-on operation and optimum battery life. Switching frequency is user programmable from 200 kHz to 2.4 MHz to optimize efficiency while avoiding critical noise-sensitive frequency bands. High-switching frequency and a small package size (3 mm x 3 mm DFN-10 or thermally enhanced MSOP-10E) keeps the external capacitors and inductor small to provide a compact, thermally efficient footprint.

The LT3480 uses a high efficiency 3 A, 0.25 Ohm switch, with the necessary boost diode, oscillator, control and logic circuitry integrated on-chip. Low ripple burst mode operation is said to maintain high efficiency at low output currents while keeping output ripple below 15 mV peak-to-peak. Linear Technology said special design techniques and a new high-voltage process enable high efficiency over a wide input voltage range while the part's current mode topology enables fast transient response and excellent loop stability. Other features include external synchronization (from 250 kHz to 2 MHz), a power good flag and soft-start capability.

The LT3480IDD and LT3480IMSE are tested and guaranteed to operate from a -40 °C to 125 °C operating junction temperature.

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