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Original question:

MCT8329EVM: No live data displayed and device burned.

MCT8329EVM: VREG_EXT_FET

Babji Bommana
Prodigy 100 points
Part Number: MCT8329EVM
Other Parts Discussed in Thread: MCF8329A

Tool/software:

If I change the jumper from position 1-2 to position 5-6 in J12, after sometime the I2C is automatically disabling but no faults from driver or controller.

  • 0
    TI__Mastermind 24860 points

    Hi Babji,

    If the jumper on J12 is moved from position 1-2 to position 5-6 the source to VREG changes from AVDD to the external MOSFET (Q7). The external MOSFET requires R56 to be populated with at least a 0 ohm resistor so that GCTRL can be used to provide control to the gate of the MOSFET. Without GCTRL being connected to the MOSFET, VREG does not receive 3.3V which means the digital core of the MCF8329A is not powered.

    R56 was depopulated since when VM is set higher than 40V, R56 is populated, and J12 was not in position 5-6 the GCTRL pin can become damaged.

    To use position 5-6 of J12, you will need to populate R56 and we recommend to not move the J12 jumper to prevent device damage while R56 is populated.

    Regards,

    Joshua

  • 0 in reply to Joshua Horlander Cruz
    Prodigy 100 points

    Hi Joshua,

    R56 is still there. I didn't depopulated. But still the issue is there.

    (after sometime the I2C is automatically disabling but no faults from driver or controller).

  • 0 in reply to Babji Bommana
    TI__Mastermind 24860 points

    Can you provide a capture of the voltage on DVDD, VM, AVDD, and the SPEED/WAKE pin starting from when the device is fine to when I2C is disabled?

    Also can you check what the value of DRV_MODE in DEVICE_CONFIG (0xAA) while the device is active? If this is set to 1b then the device may be going into sleep mode.

    Regards,

    Joshua