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Altera_Forum
Honored Contributor I
904 Views

MAX10 IO Buffer output impedance

Hi, 

 

I was just wondering whether anyone have idea regarding typical value of MAX10 GPIO's output impedance.  

 

Thanks in advance. 

 

Best 

-Taufiq
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4 Replies
Altera_Forum
Honored Contributor I
76 Views

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
Honored Contributor I
76 Views

 

--- 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
Honored Contributor I
76 Views

 

--- 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
Honored Contributor I
76 Views

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.

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