MAX10 IO Buffer output impedance

[Altera_Forum]

Hi, 

 I was just wondering whether anyone have idea regarding typical value of MAX10 GPIO's output impedance.   Thanks in advance.  Best -Taufiq

[Altera_Forum]

Best answer is 'it depends'. What I/O type are you using? Do you enable the OCT (on chip termination) or not? There is not a simple answer to that question.

[Altera_Forum]

--- Quote Start ---  Best answer is 'it depends'. What I/O type are you using? Do you enable the OCT (on chip termination) or not? There is not a simple answer to that question.  --- Quote End ---    I am using 3.0V LVCMOS with max current output and fastest slew rate. No, I don't enable OCT.  Thanks ak6dn btw for replying. -Taufiq

[Altera_Forum]

--- Quote Start ---  I am using 3.0V LVCMOS with max current output and fastest slew rate. No, I don't enable OCT.  Thanks ak6dn btw for replying. -Taufiq  --- Quote End ---    Well, in the Max10 datasheet I/O electrical specs (have you read that?) 3.3V LVCMOS is rated at Vol of 0.2V at Iol of 2mA; this is 100ohm worst case, typical will be lower.  3.0V LVCMOS has a (wierd? questionable?) spec of Vol of 0.2V at Iol of 0.1mA (is this real or a typo?). If real this would be 2000ohm worst case, typical will be lower.

[Altera_Forum]

Output impedance can be best derived from I/V slope in output characteristics defined in IBIS files. I see a range of about 6 ohms with 16 mA drive strength up to 30 ohms with 4 mA drive strength for LVCMOS30 typical curves.