如何理解total resistance seen at low level output voltage

只看该作者 · 2008-10-13 15:37

Item                      Symbol    Min    Max    Unit
Input leakage current                -10    10    μA
Input current                        0.1    1.5    mA
Sink current                         TBD    TBD    TBD
RON + RSER                           3.3    10    KΩ

Sink current = current into output port at low level output voltage
RON + RSER = total resistance seen at low level output voltage
These 2 information will allow the radio application to design the pull-up resistor required.
一个电路板对外通讯采用i2c接口，现在客户要求提供sink current和RON + RSER两个值，从字面上来说sink current是低电平输出时流入的电流即灌电流，ic提供的资料是2mA。RON + RSER字面意思是低电平输出时的总电阻，这个具体是什么呢？是上拉电阻么，如果是上拉电阻的话，又何必多此一举呢，直接提pull-up resistor 不就OK了，不明，请帮忙?