April 12, 2006 -- National Semiconductor Corp. has added four new products to its LM274x family of synchronous buck controllers, including the LM2747, the industry's first voltage-mode pulse width modulation (PWM) synchronous buck controller that offers 1% voltage feedback accuracy across an extended industrial temperature range. All four controllers provide precise core regulation in ASICs, DSPs and FPGAs. They are also designed to work at higher frequencies, which reduces the power solution footprint.

"These additions to National's LM274x family of controllers have a feature set that is optimized for powering existing and future generations of digital cores," said Michael White, Business Unit Director for National Semiconductor's Power Management Group. "This combination of complex-load- specific features and precision means that designers powering ASICs, FPGAs and DSPs can use a single LM274x controller to achieve best-in-class performance with a minimal footprint."

The LM2747 offers 1% voltage feedback accuracy across an extended industrial temperature range of -40degC to +125degC, particularly significant for cores operating below 1V. It also has a 40-ns minimum ontime, capable of providing an output of 0.6V from a 12-V rail at a switching frequency of 1MHz. In addition, the LM2747 feature set includes pre-bias load start-up capability, soft-start with tracking, a precision enable for sequencing of power rails, and external clock synchronization to reduce interaction with other supplies and sensitive load circuitry.

The LM2746 has the same performance as the LM2747 but does not include the pre-bias load start-up capability or the external clock synchronization feature. The LM2745 has the same feature set as the LM2747, but offers reduced voltage feedback accuracy of 1.5% over the extended temperature range. The LM2748 has the same accuracy as the LM2745, but without an external clock synchronization feature.

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