DC/DC Step-Down Controller Draws only 80uA in Sleep Mode

9th February 2007

ES Admin

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Linear Technology has introduced the LTC3835, a very low quiescent current step-down DC/DC synchronous controller. The LTC3835 draws only 80uA in sleep mode, making it ideal for preserving battery energy in applications such as automotive navigation or battery-powered monitoring devices where the system remains semi-active when the engine or the power is off.

The LTC3835's input supply range of 4V to 36V is wide enough to protect against high input voltage transients and continues to operate during a cold crank condition. The LTC3835 features a ± 1% internal reference and can provide an output voltage from 0.8V up to 10V, making it perfect for the higher voltage supplies typically required for audio systems, analog tuners, and CD/DVD players. The controller can deliver up to 20A load current at efficiencies as high as 95%. The LTC3835 is rated for operation from -40°C to 85°C and has a maximum operating junction temperature of 125°C.

The LTC3835's constant frequency, current mode architecture provides excellent line and load regulation. The IC smoothly ramps the output voltage during startup with its adjustable soft-start and tracking features. The operating frequency is adjustable from 250kHz to 550kHz and can be synchronized to an external clock from 140kHz to 650kHz. Output overvoltage and overcurrent (short circuit) protection are integrated.

The LTC3835 is available in two versions. The LTC3835 version offers PolyPhase® operation for current sharing multiple ICs for delivery of higher output current. The LTC3835 is offered in 20-lead TSSOP and 4mm x 5mm QFN packages, whereas the LTC3835-1 is housed in the smaller 16-pin SSOP and 5mm x 3mm DFN packages. Pricing for 1,000-piece quantities starts at $3.40 each.