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TPS65218: TPS65218 data sheet revision C

Michi Yama
Guru 10030 points
Part Number: TPS65218
Other Parts Discussed in Thread: AM4378

Hi,

I recieved one PCN recently. It is for revision up data sheet of TPS65218 rom B to C.

According to the Revision history of data sheet, many items are changed.

For example,

In Figure 1-1. Simplified Schematic,

INT_LDO pin's capacitor value is changed from 100nF to 1uF.

L5 pin's inductor value is changed from 10uH to 1.5uH.

SDA/SCL pin's resistor value are changed from 4.7k ohm to 100k ohm.

Also, DCDCx output voltage range are changed.

My customer uses TPS65218 with AM4378. Their design is based on AM437x StarterKit. But they had refered older data sheet (rev.B) of TPS65218 for their board design.

So I am afraid AM4378 may not work with new TPS65218 spec(I 'don't know TPS65218 has new silicon or not). Is this new data sheet of TPS65218 no effect to older AM4378 board design?

Please advise me.

Best regards,

Michi

  • 0
    TI__Mastermind 30260 points
    Michi,

    I assigned this post to an engineer who is familiar with the TPS65218 device and should be able to help you interpret the impact of the PCN.
  • 0
    TI__Expert 4155 points
    Michi,

    The datasheet revision from B to C did coincide with the B1 silicon revision.

    If it is at all possible I would recommend using the external component values in rev.C of the datasheet.

    The design world likely work with the old components but it would be more likely to have issues.

    Thank you,
    Nick
  • 0 in reply to Nick Jakse49
    Guru 10030 points
    Dear Nick-san,

    Thank you for your quick reply.

    My customer would like to know the reason why the external component value was changed. Depend on its reason, customer
    consider should change thier components or not.
    Please advise me.
    I appreciate your quick reply.

    Best regards,
    Michi
  • 0 in reply to Michi Yama
    Guru 10030 points
    Dear Nick-san,

    I have more question.

    My customer designed their schematic based on Rev.B data sheet. As you know, the pull-up resistor of SDA/SCL pin is changed from 4.7kohm to 100kohm. If customer does not changed the value of the resistor, what is happened? Is I2C communication are failed? Or other issue happened?

    Also there are many changes in the Electrical Characteristics section.
    For example,
    there are changed the value of ceramic capacitor. DCDC1,DCDC2(1.1V BUCK)Cout from 500 uF to 100uF

    If customer does not change the capacitor value, is there any bad influences to customer's schematic?

    Please let me know.
    Best regards,
    Michi
  • 0
    TI__Expert 4155 points

    Michi,

    I looked into this some more but finding all the reasons for all of the changes to the datasheet may take some time. Here is what I have found so far on the details you pointed out.

    1. The changes in the DCDCx voltage ranges are because the previous datasheet was incorrect. The voltage ranges in the rev.C are correct.
    2. The L5 specs are the same across both datasheets. 10uF is the typical value. The spec table is better to go off of than the schematic.
    3. I can’t see any issue with using the smaller SCL/SDA pull-up resistors. The larger values would lower current consumption, but that is about it.
    4. The INT_LDO capacitor still has the same spec range from rev.B to rev.C. It looks like the rev.B schematic just used the minimum value, and rev.C uses the typical value that was identified in rev.C. 1uF would probably be better to use, but both values are in spec.
    5. Cout for DCDC1,2 looks like the maximum value was changed from 500uF to 100uF in the specs. I am not sure of the reason for it, but I would recommend that capacitor be changed.

    If you identify any other specific changes that you need to know about please let me know.

    Thank you,
    Nick

  • 0 in reply to Nick Jakse49
    Guru 10030 points
    Dear Nick-san,

    Thank you for your cooperation.

    Regarding4, it is written the below in the page 12 of the datasheet.
    (2) 500-µF of remote capacitance can be supported for DCDC1/2.
    What is "remote capacitance"? Is 500uF also ok for new datasheet?

    Then I have more question. Please see the below.
    1) In page10, Input voltage for LS3 ---- MIN 1.8V , MAX 0V. I think MAX 0V is typo. Is correct "10V"?

    2) In page 10, input voltage for LS2 ---- MIN 3V, MAX 5.5V. I think MIN3V was changed. Correct is 4V. Is my understanding right?

    3) From Revision history,
    • Changed power-good threshold, V OUT falling values for DCDC4 (3.3-V BUCK-BOOST) V PG from 96% MIN and 97% MAX : to 95.9% MIN and 97.1% MAX in the Electrical Characteristics section. ............... 14
    I can't this parameter in the list of page 14. 95.9 ----> 94.9, 97.1 ----> 96.1 ? the value of revision history is wrong?

    4) From Revision history,
    • Added new Note 2 in the Electrical Characteristics section ....................20
    I can't find Note2 in page 20. Does it exist?

    Please advise me again.

    I appreciate your quick reply.

    Best regards,
    Michi
  • 0 in reply to Michi Yama
    TI__Expert 4155 points
    Michi,

    I believe the remote capacitance that is mentioned in the note refers to the capacitance of the load attached to DCDC1/2, not the output capacitor that is located right at the PMIC, so I would recommend changing that output capacitor.

    To answer your additional questions.

    1. You are correct. 0V is a typo and should say 10V

    2. You are correct again. 4V is the min voltage.

    3. You are correct again. The revision history is wrong. The 94.9% and 96.1% that are in the spec table are correct.

    4. I believe the note this is talking about is the note about the 500uF remote capacitance on DCDC1/2. The page number appears to be off.

    Thank you,
    Nick
  • 0 in reply to Nick Jakse49
    Guru 10030 points
    Nick-san,

    Thank you for your cooperation.

    I have one more question.

    According to the rev.C datasheet, "PRE_OFF" State is added suddely in Power-up sequence section and Moeds of Operation Diagram.
    Why is "PRE_OFF" state added in new datasheet? You said that Silicon revision is same. It means "PRE_OFF" state exists from beginning.
    If "PRE_OFF" is new feature, I must notice its influence to my customer.

    Please advise me again.
    I appreciate your quick reply.

    Best regards,
    Michi
  • 0 in reply to Michi Yama
    TI__Expert 4155 points
    Michi,

    There shouldn't be any difference in the operation of the device. I think the modes of operation diagram was changed to clarify the difference between states when the PWR_EN pin is set low but the device still has power, and when the device completely loses power.

    Thank you,
    Nick