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BQ27742EVM: BQ27742-G1

Part Number: BQ27742EVM

Hi,

BQ27742 EVM board worked fine when I bought. Later the IC got damaged. Initially it has 2.5V on VREG. But later it went to 0v. I'm not in SHUTDOWN mode, because I'm not sending shutdown command. But, in my EVM to use internal I2C pull ups, I should short J7 and J9 jumpers as mentioned in sluuax8.pdf  Page No: 7. I'm taking voltage to pull ups from VREG in EVM. The SCL and SDA get 3.3v from MSP controller GPIO pins. For I2C from microcontroller I'm doing software bit bang of GPIO's. Is there any chance that the SCL voltage(3.3v) is causing my BQ processor IC damage. I'm seeing fluctuation on VREG, sometimes it is giving 2.9v, 3v. Can you tell me whether this is causing any damage of IC. 

Thank you,

Kavya.

  • Hello Kavya,

    Absolute max on VREG=2.75V

    Since you have 3.3V pulll-up on MSP side, this is causing the absolute max to be exceeded. This is causing damage to the IC. You do not need to enable internal pull-ups for your configuration.