• State Resolved
  • Locked Locked
  • Replies 8 replies
  • Answers 3 answers
  • Subscribers 64 subscribers
  • Views 119 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

PMICLOADBOARDEVM: PMICLOADBOARDEVM spec

Hailiang Zhang
Genius 11040 points
Part Number: PMICLOADBOARDEVM

Tool/software:

Hi Team,

Could you pls help with below question about the PMICLOADBOARDEVM?
1. Is there more information/document regarding this EVM other than the UG?
2. What is the input voltage range for the load?
3. What is the maximum current that each channel can support?
4. What is the maximum transient frequency that the EVM board can support?
5. What is the maximum slew rate (A/us) that the EVM board can support?

Thanks in advance.

Regards,
Hailiang

  • 0
    TI__Genius 9667 points

    Hi Hailiang, 

    Thanks for reaching out on E2E.

    1. Unfortunately, the User Guide is the only documentation available for the PMICLOADBOARDEVM
    2. The input voltage range is stated as ±6 V - ±11 V. Recommended input voltage is ±11 V.
    3. Maximum current is unspecified. The user guide does demonstrate up to 6 A (isolated), 12 A (parallel). 
    4. Can you clarify what is meant by transient frequency?
    5. There is no specified maximum slew rate. Slew rate of the load will be equivalent to the slew rate of the signal input.

    Best Regards,
    Sarah

  • 0 in reply to Sarah Lao
    TI__Genius 11040 points

    Hi Sarah,

    Pls check below reply.

    Sarah Lao said:
    The input voltage range is stated as ±6 V - ±11 V. Recommended input voltage is ±11 V.

    The +/-11V seems the input supply for op-amp. I am asking about the load input.

    Sarah Lao said:
    Can you clarify what is meant by transient frequency?

    Transient frequency here is referring to the on and off loading time, or turn on, turn off frequency.

    Sarah Lao said:
    There is no specified maximum slew rate. Slew rate of the load will be equivalent to the slew rate of the signal input.

    I believe the FET cannot followed the signal input directly as there are additional R & C on the gate of the FETs. 

    Or is there an upper limit on the frequency at which the slew rate of load can better follow the slew rate of signal input?

    Regards,
    Hailiang

  • 0 in reply to Hailiang Zhang
    TI__Mastermind 21935 points

    Hi Hailiang,

    Just to add some information:

    • The PMICLOADBOARD can be paired with a PCB socket to significantly improve the frequency and slew rate performance. I've seen slew rates on transient edges as fast as 100ns. With faster slew rate you can push the load frequency quite high (We've used this board to test 1MHz loading in some applications). Any added wires or connection between the load board and the point of load on your DUT will degrade the slew performance. However, at slower frequencies this is less impactful so it depends on your test case.
    • The FETs appear to be capable of at least 8.7A DC and with two FETs per load channel that should give you at least 16A of load per channel but I've never tested a device up to that point. In my testing I've only used 7.5A per channel but I haven't seen any issues at that current. I believe it can go up to 10 or even 12A according to the FET datasheet (See the BOM list in the User's Guide)

    Regards,

    James

  • 0 in reply to James Steenbock
    TI__Genius 11040 points

    Hi James,

    Any comments about the the input voltage range?

  • 0 in reply to Hailiang Zhang
    TI__Mastermind 21935 points

    Hi Hailiang,

    The input voltage for the load should match the current capability with a scale of 50mV / A (per channel)

    So if one channel can only do 12A, you should only need a signal of 600mV into the channel input for the load.

    Eventually the FETs will saturate and you won't get more current by increasing the input voltage to the channel but I'm not sure where exactly this threshold sits.

    Regards,

    James

  • 0 in reply to James Steenbock
    TI__Genius 11040 points

    Hi James，

    I was asking about the voltage to be applied across the load, or the output voltage of the previous stage, not the voltage range of the control signal.

    Regards，
    Hailiang

  • 0 in reply to Hailiang Zhang
    TI__Mastermind 21935 points

    Hi Hailiang,

    The only other voltage you need it the board input voltage which should be +11V, -11V, and GND into the 3-port terminal. This, plus the load profile voltage should be all you need to run the board.

    The full range of this board input voltage is +/-6V up to +/-11V.

    +/-11 is recommended for best performance and it is what we use in the lab here.

    Regards,

    James

  • +1 in reply to James Steenbock
    TI__Mastermind 21935 points

    Hi Hailiang,

    Just recording here for anyone who reads.

    The FETs are rated for 30V Vds, but the resistors in the current path need to be able to handle the load you plan to apply on the DUT.

    Regards,

    James