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Original question:

BQ25121: Excess quiescent current draw beyond specification when enabling the LDO in some devices

BQ25120A: Excess quiescent current draw when replacing the BQ25121 with BQ25120A

Dajgoro Labinac98
Prodigy 110 points
Part Number: BQ25120A
Other Parts Discussed in Thread: BQ25121, , BQ25121A

Hi.

Due to issues with the BQ25121 I have replaced it with the BQ25120A and that causes a 0.5mA quiescent current draw.
Register settings were kept the same on both, since the firmware is the same on both cases.
When using the BQ25121 on the same board there is no such problem. What could be causing the issue?

  • 0
    TI__Genius 12485 points

    Dajgoro,

    Could you help me understand a little more about the issue? Where is the Iq being measured? VIN or VBAT?

    Note that the VSYS voltages are different. Can you step up the VSYS voltage to 2.5V to make sure nothing on the system is consuming different levels of Iq at different voltage levels being provided?

    regards,

    gautham

  • 0 in reply to Gautham
    Prodigy 110 points

    Hi,

    I'm measuring the power draw from the battery.
    As I said, with the BQ25121 the power consumption from the battery is as it should be, but when I desolder the BQ25121 and solder the BQ25120A without touching anything else there is a 500uA extra power draw.
    The output voltage is in both case adjusted to 1.8V, even when its to 2.5V it should be nowhere near as high.
    I ordered the BQ25121A from mouser, previously they had vanished for a while and now they seem to be back, so will test with that.

  • 0 in reply to Dajgoro Labinac98
    TI__Genius 12485 points
    Dajgoro,

    If i understand correctly on the units with BQ25121, you are dialing back the VSYS to adjust to 1.8V. let me know what happens with BQ25121A.

    Also is /MR asserted when you are reading these measurements? Is /CD pin low? Are you performing i2C transactions?

    regards,
    gautham
  • 0 in reply to Gautham
    Prodigy 110 points
    Yes, setting it to 1.8V tho I tried fiddling with the settings, nothing changes.
    No I2C is performed after initial startup, device operation does not seem to have any effect.

    Is there anything at all different in the two models except the initial voltage?
    Is the internal IC layout the same? Does it use the same manufacturing process?
  • 0 in reply to Dajgoro Labinac98
    TI__Genius 12485 points

    We fixed a couple behaviors that were causing issues in some corners of glitchy /MR and VIN situations. For a complete list, refer to this post. 

    The manufacturing process is very same. the datasheet parameters are also the same so you can be assured that the device will match the datasheet. 

    e2e.ti.com/.../632901