bobsun
Full Member level 2
Hi,
How could I determine the required clock characteristics for a particular IC?
Many datasheets list only frequency requirements. However, there are also important factors including:
1. Voltage.
2. Shape, which can be either sinusoid or square wave
For standard I/O pins, there are widely-adopted conventions that logic low is below 30% of DVDDIO, and logic high is above 70% of DVDDIO.
But does this apply to clock input? There can be several groups of power supply, including analog and digital at different voltages. So how can voltage and shape characteristics of input clock be known given these information?
Is there any convention here, or different chips has different specification?
Bob
How could I determine the required clock characteristics for a particular IC?
Many datasheets list only frequency requirements. However, there are also important factors including:
1. Voltage.
2. Shape, which can be either sinusoid or square wave
For standard I/O pins, there are widely-adopted conventions that logic low is below 30% of DVDDIO, and logic high is above 70% of DVDDIO.
But does this apply to clock input? There can be several groups of power supply, including analog and digital at different voltages. So how can voltage and shape characteristics of input clock be known given these information?
Is there any convention here, or different chips has different specification?
Bob
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