Power management ICs suit XScale devices

National Semiconductor has added a flexible power management unit and highly integrated DC/DC convertor to its family of digitally programmable, multiple-output power management devices.

National Semiconductor has added a flexible power management unit (PMU) and highly integrated DC/DC convertor to its family of digitally programmable, multiple-output power management devices.

The LP3971 PMU and LM3370 dual-channel, step-down DC/DC convertor feature a digital I2C compatible interface that enables design engineers to customise electrical specifications such as output voltage and switching modes to the end application.

The digital interface provides the flexibility to use the same device for multiple solutions that require different output voltages, as well as to maximise power savings in the end application.

The highly-integrated LP3971 flexible PMU and LM3370 DC/DC convertor both include buck regulators that provide more than 90% efficiency over the entire load current range.

Power consumption is further minimised through a dynamic voltage-scaling feature that enables the design engineer to modify the output voltage in real time to match the computing workload and clock frequencies of the corresponding processors.

The end result is longer battery life in energy-sensitive systems such as cellphones and personal media players.

"The digital programmability and efficiency of National's new power management devices are ideal for the Intel XScale microarchitecture".

"They also support the advanced power management modes of Intel's newest application processor platform family (codename Monahans), which enables longer talk time and extended run time for emerging multimedia applications or services", said Mark Casey, General Manager of Intel's Applications Processor Business Unit.

The LP3971 flexible PMU is a fully integrated solution for next-generation multimedia processors.

The LP3971's digital programmability and extensive features offer a comprehensive, yet extremely simple to use, power solution for multidomain digital systems.

The LM3370 dual-channel, step-down DC/DC convertor complements the LP3971 flexible PMU by offering a stand-alone programmable solution.

Two digitally controlled buck regulators in the LM3370 can be used in conjunction with National's LP3990 and LP5900 linear regulators to offer a flexible and customised power domain.

"While manufacturers such as Intel continually reduce the power consumption of their line of processors, National's goal is to extend this energy conservation by combining the highest conversion efficiency with an advanced feature set in the power management device", said Gianluca Colli, Business Unit Director in National Semiconductor's Power Management Division.

The LP3971 PMU integrates three high efficient, 1600mA programmable buck convertors and six programmable LDOs that enable it to meet the dynamic power requirements of SoCs such as Intel XScale processors.

The LP3971 is available in a small, 40-pin LLP package that measures 5 x 5 x 0.8mm.

The LP3971 has an input range of 2.7 to 5.5V and output voltage ranges of 0.8 to 3.3V for the buck regulators and 1 to 3.3V for the LDOs.

With efficiency equal to that obtained with a switching regulator, two of the LDOs can be used as post regulators with low input voltage and a small drop from input to output.

The dynamic, wide output voltage range allows the LP3971 to achieve maximum flexibility across many application processors and different application needs.

For programming the regulator settings of the LP3971, the I2C compatible interface with software control is included in the evaluation kit.

Additional features of the LP3971 include a backup battery charger, power-on-reset function to protect the processor from input voltage fluctuations and ability for the processor to control the enable and disable of the regulators over the I2C compatible interface.

Packaged in a very small, 16-pin LLP package that measures 4 x 5 x 0.8mm, the LM3370 DC/DC convertor supplies a 600mA load per channel at highly efficient levels.

The excellent efficiency is accomplished by intelligent automatic switching between PWM and PFM mode.

The addition of industry-leading quiescent current of 16uA per channel in PFM mode provides the longest battery life for battery-powered devices.

The output voltage range is 1 to 2V for the first output and 1.8 to 3.3V for the second output.

The output voltages can be stepped up or down in 50 and 100mV steps, respectively, using the I2C interface.

Additional features of the LM3370 include a power-on-reset function to protect the processor from voltage fluctuations and independent enables for simple and effective power sequencing.

The LP3971 and LM3370 are available now.

The LP3971 is priced at $4.00 each and the LM3370 is priced at $2.10 each in 1000-unit quantities.

Back to top