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Clock Voltage on Max7000

Altera_Forum
Honored Contributor II
‎04-19-2012 06:48 AM
1,475 Views

Hi there! 

 

I'm doing a PCB design which includes a microcontroller and a MAX7000 CPLD. As the controller's IOs work on 3.3V we decided to run the MAX7000's IOs also on 3.3V. The core is using 5V 

 

In the MAX7000 datasheet I couldn't find any information about the clock voltage. Can i use a 5V oscillator, even if the IO voltage is on 3.3V? 

 

Thanks for your support 

Simon
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Altera_Forum
Honored Contributor II
‎04-19-2012 04:02 PM
531 Views

If you read the MAX7000 data sheet thoroughly, you'll notice: 

- Input buffers are supplied from VCCINT and thus independent of VCCIO. 

- MAX7000 inputs have a TTL level specification, minimal high level is 2.0 V. 3.3V CMOS and 5V CMOS/TTL levels are fine to drive the inputs, including clock.
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Altera_Forum
Honored Contributor II
‎06-05-2012 12:27 PM
531 Views

Thank you for your advice. In a few days i'll see if it was correct...:)

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