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TPS659037: pmic power on problem

Part Number: TPS659037
Other Parts Discussed in Thread: AM5718,

PMIC : TPS6590379ZWSR

SITARA : AM5718AABCXEA

PMIC IS GETTING PROPER INPUT SUPPLY,CLK 16.384MHz is ok, BUT WE ARE UNABLE TO OBSERVE PMIC OUTPUTS.OUR DESIGN ALSO ATTACHED .

7043.pmic ic sch.pdfpmic smps sch.pdf

  • Hello, Kalpana,

      Please check followings:

    1. Please check your PMIC schematics with the reference design: AM571x Industrial Development Kit (IDK) Schematic (SPRR242.ZIP).
    2. Above reference design has the VUSB_VBUS2 for VBUS input connected, yours has the pin connected to GND.
    3. If you have VRTC_OUT=1.8V?
    4. If nSLEEP pin has high "PMIC_EN" input?
    5. If you push the power on/off button SW3 B3SL to turn it on? 
    6. What's the current reading of the main power supply? 
    7. Do you have a good power on board with the same design? 

    Thanks!

    Phil

  • 1.okay

    2.we are not using USB in our design

    3.vrtc_out-1.8v only we have connected,ldo-2 output also 1.8v only

    4.nsleep pin has high, PMIC_EN signal from sitara processor (optional) in AM5718 EVM R922&R923 are NC's .

    5.We have placed switch in our design also and pressed it after powering on ,but we are unable to observe any outputs.

    6.Current drawn from board:110mA, we have given input Voltage:12V ,input current:3A

    7.Yes power is proper. generating 3.3V and 5V from 12V input using LTM4644IY. 

  • Hello, Kalpana,

     How many boards you have made in total? how many of them have this issue?

      Can you share a higher resolution and searchable PDF schematics so I can do better review?

     Can you check again with following ON Requests?

    ON requests are used to switch on the TPS659037 device, which transitions the device from the OFF to

    the ACTIVE state. Table 5-9 lists the ON requests.

    Table 5-9. ON Requests

    EVENT MASKABLE POLARITY COMMENT DEBOUNCE

    RPWRON (pin) No Low Level sensitive 16 ms ± 1 ms

    PWRON (pin) No Low Level sensitive N/A

    Part of interrupts

    (event)

    Yes (INTx_MASK register.

    Default: Masked) Event Edge sensitive N/A

    POWERHOLD (pin) No High Level sensitive 3 - 5 ms typical

    Thanks!

    Phil

  • hi sir,

    made 2 boards in total ,2 boards have the same issue.

    Table 5-9 : 2 requests are already maintained on board PWRON -low & POWERHOLD_high 

    Could you please share your mail id I will share schematics offline.

  • hi sir,

    we are getting LDOVRTC output -1V8 ; not getting output from LDO2-1V8 

  • Hello, Kalpana,

      Do you mean all other outputs working well except LDO2-1V8?

      Can you share a clear top mark from the device? We'd like to know where did you get these 2 PMIC devices. 

      

    Thanks!

    Phil

  • No sir, only LDOVRTC output is coming from PMIC. We are not getting any other outputs. Purchased these two PMIC devices from Mouser electronics. OTP:97 1.3

  • Hello, Kalpana,

      Thanks for the information. I'll check with our production engineer if we know any issue with this OTP devices from other customers; and then update you tomorrow. 

      BTW, I suggest to implement a X-ray for clod soldering issue. 

    Thanks!

    Phil

  • Sir,

    is there any problem with the design of our PMIC.

  • Hello, Kalpana,

      I don't find any problem with the design so far; and I'm waiting for our product engineer to check this OTP history. 

      BTW, have you done X-ray scan for clod soldering? Assembly process issue can cause same problem for many boards.

    Thanks!

    Phil