Get Started with the KITVR55-FSSKTEVM

This page will help guide you through the process of learning about your KITVR55-FSSKTEVM board.

2. Get to know the hardware

2.1 Board features

  • VBAT power supply connectors (Jack and Phoenix)
  • VPRE output capability up to 1.0 A (socket limit) 3.3 V / 3.8 V / 4.1 V / 5.0 V
  • VBUCK1/2 in Standalone mode (default) or Multiphase mode
  • VBUCK3
  • VBOOST 5.0 V or 5.74 V, up to 800 mA
  • LDO1 and LDO2, from 1.1 V to 5.0 V, up to 400 mA
  • Ignition key switch
  • Embedded USB connection for easy connection to software GUI (access to I2C-bus, IOs, RSTB, INTB, Debug, MUX_OUT, regulators)
  • LEDs that indicate signal or regulator status
  • Support OTP fuse capabilities
  • USB connection for register access, OTP emulation, and programming
  • Voltage monitoring jumper setting

2.2 Board description

The KITVR55-FSSKTEVM provides flexibility to play with all the features of the device and make measurements on the main part of the application. The KL25Z MCU installed on the board, combined with the FlexGUI software allows access to the registers in read and write mode. All regulators are accessible through connectors. Nonuser signal, like DC-to-DC switcher node is mapped on test points. Digital signals (SPI, I2C, RSTB, etc.) are accessible through connectors. Pin WAKE1 has a switch to control (ignition) them. A VBAT switch is available to power on or off the device.

The main purpose of this kit is to burn the OTP configuration. This kit can be operated in Emulation mode or in OTP mode. In Emulation mode, as long as the power is supplied, the board configuration stays valid. The OTP mode uses the fused configuration. The device can be fused three times. In OTP mode, the device always starts with the fused configuration, except if the user wants to overwrite OTP configuration using Emulation mode. This board is able to fuse the OTP without any extra tools or board.

Note: Due to the socket, this kit is not optimized for performance measurement or current higher than 1.0 A.

2.3 Board components

Overview of the KITVR55-FSSKTEVM evaluation board

  1. VBAT Jack connector
  2. VBAT three position switch
  3. VBAT Phoenix connector
  4. LDO1/LDO2 power supplies
  5. VPRE power supply
  6. BUCK1/BUCK2 power supply
  7. USB connector (for FlexGUI control)
  8. Debug connectivity
  9. Programming
  10. WAKE1 switch
  11. OTP burning voltage switch
  12. VBOOST and BUCK3 power supply
  13. Debug voltage source
  14. Compensation network selection
  15. VDDIO selection
  16. RSTB connection to MCU
  17. RSTB and INTB signals
  18. VMON1 and VDDI2C selection

2.4 Additional board support

Refer to UM11303, KITVR55-FSSKTEVM evaluation board - User Guide user manual for additional details on the featured components.

3. Configure the hardware

To configure the hardware, complete the following procedure:

  1. Install jumpers for the configuration.

    Table 1. Jumper configuration

    Jumper Configuration
    J17 connect 1-2 (connect 5.0 V on DBG pin from the USB)
  2. Configure switches

    Table 2. Switch configuration

    Switch Configuration
    SW1 middle position (VBAT off)
    SW2 open (WAKE1)
    SW3 open (OTP programming off)
  3. Connect the Windows PC USB port to the KITVR55-FSSKTEVM development board using the provided USB 2.0 cable.
  4. Set the DC power supply to 12 V and current limit to 1.0 A. With power turned Off, attach the DC power supply positive and negative output to KITVR55-FSSKTEVM VBAT Phoenix connector (J1).
  5. Turn on the power supply.
  6. Close SW2.

Note: At this step, the product is in debug mode and all regulators are turned Off. The user can then power up with OTP configuration or configure the mirror registers before power up. Power up is effective as soon as J17 jumper is removed.


3.1 Additional board support

Refer to UM11303, KITVR55-FSSKTEVM evaluation board - User Guide user manual for additional details on the hardware configuration.

4. Install software

4.1 Prepare graphical user interface operating environment

Download and run the software.

4.2 Install FlexGUI software package

The FlexGUI software does not require any installation. Unzip the folder contents to a desired location on your computer.

  1. If necessary, install the Java JRE (Java SE Runtime Environment) available at and Windows 7 FlexGUI driver.
  2. Download the latest FlexGUI (32-bit or 64-bit) version, available at
  3. Run the flexgui-app-vr5500-fs5502.exe file.
  4. Restart the computer after successful download.

4.3 Additional software support

Refer to UM11303, KITVR55-FSSKTEVM evaluation board - User Guide user manual for additional software details.

Start embedded application development.

5. Learn more

5.1 Product summary page

The product summary page for VR5500 is at

5.2 Tool summary page

The tool summary page for KITVR55-FSSKTEVM board is at

The page provides overview information, technical and functional specifications, ordering information, documentation, and software. The Get Started provides quick-reference information applicable to using the KITVR55-FSSKTEVM board, including the downloadable assets.

5.3 References

In addition to our VR5500: High Voltage PMIC with multiple SMPS page, you may also want to visit:

Application pages:

Hardware pages:

Software pages:

Community page:

5.4 BUY the board

KITVR55-FSSKTEVM: Evaluation board featuring the VR5500