• Fully programmable LP3906 Power Management Unit
• Freescale MC9S08 8-bit microcontroller to manage the voltage setting and sequencing
• Visual Basic PC application to interact with the board and its settings

Design Description

The LP3906 Smart Power Board provides a complete, multirail solution for FPGAs, Microprocessors, or any other systems requiring multiple voltages, special power sequencing, and boot management. This solution utilizes the National Semiconductor LP3906 Power Management Unit and an 8 bit microcontroller to manage the features of the PMU. There are more than 400,000 combinations of initial voltage values for the output voltages, this solution can provide them all regardless of the chip hard-coded startup values.
An RS-232 port and Windows application are also provided to simplify evaluation of the solution using a PC; however, this is not required for a final system implementation.

LP3906 Key Specifications:

Two Buck Regulators

• Buck 1 0.80-2.0V
• Buck 2 1.0-3.5V
• Up to 96% efficiency
• Up to 1.5A output current

Two Low Dropout Linear Regulators

• Programmable V OUT of 1.0V-3.5V
• ±3% output voltage accuracy
• 300mA output currents
• 25mV (typ) dropout

•	RD-161 Reference Design Document
•	Design Files (Schematic, Board Layout, Gerber, BOM, firmware and VB application)

Additional Resources

Board Photo

LP3906 Smart Power Board Key Features

• Utilizes the National Semiconductor LP3906 Power Management Unit and the low cost Freescale 8-bit microcontroller
• Solution provides user control over all default voltage startup values, boot control (reset lines, enable lines, etc), order and time sequencing of rails. Power down sequencing is also possible with modifications to the firmware.
• Utilizes LP3906 GPIOs and / or MCU GPIO for boot control.
  • Power-on Reset
  • Peripheral Reset
  • Control of reset polarity and drive type ("open drain" like, push-pull)
• Board also provides jumpers to allow insertion for current monitoring of loads or input.
• The control values stored in the MCU flash can be easily modified for FPGAs, DSPs, other processors, and any other multi-rail devices without changing the firmware which speeds time to market.

LP3906 Device Special Features

• Compatible with advanced applications processors and FPGAs
• 2 LDOs for powering Internal processor functions and I/Os
• High speed serial interface for independent control of device functions and settings
• Precision internal reference
• Thermal overload protection
• Current overload protection
• 24-lead 5 × 4 × 0.8 mm LLP package
• Software Programmable Regulators

Designed for National by: