National rolls out new PMU, DC/DC converter

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

The new LP3971 PMU and the dual-channel, step-down LM3370 DC/DC converter feature a digital I²C-compatible interface that enables design engineers to customize electrical specifications such as output voltage and switching modes to the end application. The digital interface also allows the use of the same device for multiple solutions requiring different output voltages, as well as maximizes power savings in the end application.

Both the LP3971 PMU and the LM3370 DC/DC converter include buck regulators that provide more than 90 percent efficiency over the entire load current range. Power consumption is further minimized 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, said National.

The LP3971 PMU is a fully integrated solution for next-generation multimedia processors. Its digital programmability offers a simple-to-use, comprehensive power solution for multi-domain digital systems. The LM3370 DC/DC converter complements the LP3971 PMU by offering a standalone programmable solution. This device's digitally controlled buck regulators can be used in conjunction with the company's LP3990 and LP5900 linear regulators to obtain a flexible and customized 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," shared Gianluca Colli, business unit director in National's power management division.

Three programmable buck converters, six programmable LDOs
The LP3971 PMU integrates three highly efficient 1600mA programmable buck converters and six programmable LDOs that enable it to meet the dynamic power requirements of SoCs. The LP3971 is available in a small, 40-pin LLP package that measures 5-by-5-by-0.8mm.

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

Packaged in a very small, 16-pin LLP package measuring 4-by-5-by-0.8mm, the LM3370 DC/DC converter supplies a load of 600mA per channel at highly efficient levels, accomplished by intelligent automatic switching between PWM and PFM mode. The addition of a 16?A per channel quiescent current in PFM mode helps provide extended battery life for battery-powered devices. The output voltage range is 1V to 2V for the first output, and 1.8V to 3.3V for the second output. The output voltages can be stepped up or down in 50mV and 100mV steps, respectively, using the I?C 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 is available for $4 each, while the LM3370 is priced at $2.10 each, both in 1,000-unit quantities.