Switching regulator keeps quiescent current under 100 microamps

Dec 21, 2004 4:02 PM

Linear Technology Corporation (Milpitas, CA) has introduced the LT3434EFE, a high-voltage, burst-mode step-down switching regulator that maintains quiescent current under 100 µA. Operating within an input voltage range of 3.3 V to 60 V, the part is said to be suited for load dump and cold-crank conditions in automotive applications. Its 3A internal switch can deliver up to 2.75 A of continuous output current at voltages as low as 1.25 V.

The LT3434 is Linear Technology's first 3 A, high-voltage switching regulator to offer burst-mode operation. Its ultra-low quiescent current makes it suited for automotive applications, which use "always-on" systems that can affect battery charge life. The combination of its thermally enhanced TSSOP package and a 200 kHz switching frequency is said to keep external inductors and capacitors small and to provide a compact, thermally efficient solution footprint.

The LT3434 uses a high-efficiency 3 A, 0.1 Ohm switch, with all necessary oscillator, control and logic circuitry integrated into a single chip, the company says. Special design techniques and a new high-voltage process enable high efficiency over a wide input voltage range, and its current mode topology enables fast transient response and excellent loop stability. Efficiency is optimized over a wide output current range by employing burst-mode operation at low currents, using the output to bias internal circuitry and using a supply boost capacitor to fully saturate the power switch.

The LT3434 is offered in an E-grade version that allows operation from -40°C to 125°C and is assured by design. The I-grade is tested and guaranteed to operate over this full operating junction temperature range.

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