Power controllers are made for notebooks

Power supply controllers with digitally controlled output and fast transient performance are designed for processors and graphics chips used in notebook computers.

Semtech Corp has announced the SC457 and SC458 power supply controllers with digitally controlled output and fast transient performance for processors and graphics chips used in notebook computers.

With a built-in 7bit DAC, the output voltage of the SC457 and SC458 can be digitally programmed in 12.5mV steps from 0.3 to 1.5V for precision control over output voltages.

Both devices have a programmable DAC slew rate to minimise transient currents and audible noise.

Additionally, the devices feature a power-save function that boosts efficiency at light loads to extend battery life.

The single-phase SC457 can drive up to 30A and is packaged in an MLP5x5 32-pin (5 x 5mm) package so it is ideal for ultra small, lightweight notebook computers that need low-voltages for long battery life.

The 60A, dual-phase SC458 can seamlessly switch between single and dual-phase operation for very efficient operation with no disturbance on the output voltage.

The SC458 is provided in an MLP7x7 44-pin (7 x 7mm) package.

Both devices are lead free and WEEE and RoHS compliant.

The SC457 and SC458 feature a very fast hysteretic voltage regulation scheme for a transient response of less than 10us.

The use of hysteretic topology allows increased design flexibility and simplicity because it ensures the output is very stable and requires no equivalent series resistance (ESR).

This architecture also minimises output capacitance, reducing component counts, minimising board footprint and lowering cost.

"The SC457 and SC458 are a new generation of dedicated controllers for notebook processors, and with their battery-saving features, fast transient response and digital output programmability, we believe they offer dramatic added value over general purpose controllers", said Nejo Necar, Vice President of Marketing for Semtech's Power Management Group.

"These controllers give notebook designers a substantive choice to meet the needs of notebook families, with a single-phase device for ultra lightweight notebooks, and a dual-phase device for desktop replacement models".

For high efficiency, the SC457 and SC458 use Semtech's proprietary Smart Drive technology, which lowers ringing on the phase node and high-side FET gate node to keep efficiency high while reducing EMI and eliminating the need for snubbers or gate resistors.

Additionally, the SC458's current sensing system is based on Semtech's Combi-Sense technology that eliminates the need for lossy, external sense resistors, thus keeping efficiency high and reducing cost.

Both devices have a complete set of protection mechanisms including programmable current limit, output overvoltage protection, input undervoltage lockout and overtemperature protection.

The SC457 and SC458 are available immediately in production quantities.

The SC457 is priced at US $1.94 each in 1000-piece lots.

The SC458 is priced at $2.80 each in 1000-piece lots.

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