it looks like it's the output impedance of the transmitter. not the input kind.
help me understand it.
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it looks like it's the output impedance of the transmitter. not the input kind.
help me understand it.
Hi Haigu!
The RID values are referred to as input resistances because they are primarily used to reference the input resistance from the Signal improvement capability (SIC). To remove ringing, signals are held at an intermediate value (Active Recessive Phase) in between changing from the dominant phase to the recessive phase, as shown below. The RID values are primarily referring the different resistance values on the receiving end, where the resistance would be considered the input resistance.
It is a little confusing because it's the resistance on the data bus, so it can be an input resistance or output resistance depending on which transceiver is transmitting. The TI Team will be discussing ways to clear up any confusion in the data sheet. Hope this helps, please let us know if you have any more questions.
Zach Schmidt
thanks. I can understand now we usually use the term 'differential impedance' or 'differential input impedance'.to describe differential ciucuit, no such thing like 'differential output impedance'. this equivalent impedance is between CANH and CANL and no way we can describe it as output impedance.
but in fact when in dominant to recessive transition, the device is really changing its internal output impedance of individual CANH or CANL driver.