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Altera_Forum
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15 years ago

MAXII LED Driver AN286

Hello,

the AN 286 decribes implementing LED Drivers in MAX devices. The maximum source/sink current is dependend on the number of GNDIO/VCCIO groups.

Is a group identical to the number of GNDIO/VCCio pins? Is it theoretical possible to sink 16x 130mA using a EPM2210 (16 VCCIO/ 16 GNDIO pins)

Thanks for help

Volker

2 Replies

  • Altera_Forum's avatar
    Altera_Forum
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    15 years ago

    The answer from Altera support makes me a little bit confused.

    Does anybody understand the answer of Q2? If I have a look in the pin out file of EPM2210 I count 20 regions...

    Volker

    Following the anser of the support:

    [Q1]: Is a group identical to the number of GNDIO/VCCio pins?

    [A1]: A group means a set of I/O pins between any two VCCIO pads or any two GNDIO pads.

    As an example is quoted in the handbook, the EPM240 device has six GNDIO pads, which provide six I/O regions that can sink up to 130mΑ. If you need to sink 15mA for the outputs, you can have eight outputs per region. With the six regions of I/O between GNDIO pads, there are 48 possible outputs, each sinking 15mA.

    For more information about GNDIO grouping, refer to the MAX II Device Pin-Out Files, and the MAX 7000B Device Pin-Out Files. These files are on the Pin-Outs page of the Literature section of the Altera website.

    [Q2]: Is it theoretical possible to sink 16x 130mA using a MAXII EPM2210 (16 VCCIO/ 16 GNDIO pins)?

    [A2]: No, the maximum sink current per group is 130mA, as stated in AN 286 application note, Table 3: Maximum Source Current for Each VCCIO Group and Maximum Sink Current for Each GNDIO Group in MAX and MAX II Devices.

    16 x 130mA = 2080mA is already exceed the 130mA maximum rating, which may have adverse affects on the device.
  • Altera_Forum's avatar
    Altera_Forum
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    15 years ago

    Hi,

    Altera answered my question:

    Hi Volker,

    Yes, you are right. There are 20 regions in total. EPM2210F256C5 is a 256-Pin FBGA device. The EPM2210 will have more regions as it has more I/O pins compare to EPM240 devices, which only have 100 pins. Therefore, it is expected to have more regions in EPM2210 device.

    I replied to this answer if so its possible to sink 20x 130mA= 2600mA with this device. The FAE answered that these asumption is correct...

    Volker