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Altera_Forum's avatar
Altera_Forum
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10 years ago

Question about Power supply for EPM240

HI,

epm240 have internal LDO, epm240g does not have internal LDO. I know, i can apply 1.8v on VCCIO and vccint for EPM240G.

I know i can apply 3.3v or 2.5V on vccio and vccint when epm240(not epm240g) is used.

My questions are :

1. can i apply 1.8v on VCCIO and vccint(connected together) for EPM240( not epm240g)?

2. can i apply 2.8v on VCCIO and vccint for epm240?

thanks :o)

3 Replies

  • Altera_Forum's avatar
    Altera_Forum
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    10 years ago

    1) No. EPM240 needs 2.5V or 3.3V (as you've already pointed out). EPM240 won't work if VCCINT is at 1.8V.

    To quote the relevant notes from the datasheet:

    --- Quote Start ---

    Notes:

    1. For EPM240 devices, all VCCINT pins must be connected to either 3.3 V or 2.5 V, but not a combination of both.

    For EPM240G devices, all VCCINT pins must be connected to 1.8 V.

    2. Each set of VCCIO pins (VCCIO1 or VCCIO2) can be connected to 3.3 V, 2.5 V, 1.8 V, or 1.5 V.

    --- Quote End ---

    1a) If you meant EPM240G then yes. VCCIO & VCCINT could be powered from the same 1.8V rail.

    2) No. (But yes, possibly). 2.8V is not a voltage at which Altera operate or characterise any of their devices. 2.8V won't damage an EPM240. However, 2.8V doesn't comply with "all VCCINT pins must be connected to either 3.3 V or 2.5 V".

    It'll probably work quite happily. However, you just need to be aware that none of the datasheets cover the performance of a device operated at this voltage, nor will Altera support you should it not work.

    If you have 2.8V available then, for the sake of an extra LDO regulator, add the required 1.8V rail and use an EMP240G part.

    Cheers,

    Alex
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    10 years ago

    thanks for your help.

    I have done an trial for EPM240T100c5n, if i apply 1.74v on VCCIO and VCCINT, it works very well.

    I don't know if the internal ldo will be disabled if 1.8V is applied on vccint. the difference is that epm240 will consume more power than epm240g when 1.8V is applied on vccint.

    is there an FAE that know the details about it issue?
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    10 years ago

    It may well be working. However, the EPM240 doesn't support operating VCCINT at 1.8V. The device you have may well appear to be happy, but unless you operate it in accordance with the datasheet neither Altera nor an FAE are going to help you should things stop working.

    Cheers,

    Alex