This thread has been locked.
If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.
Tool/software:
Hi,
We will measure the internal pull down resistor of the RIN1 and RIN2, and we use the avometer connect to the RIN1 and GND,
and our end customer need the measure resistor is more than 5.2Kohm, we know it has the 5Kohm internal pull down resistor for the RIN1 and RIN2;
plesae advise if this is request is OK or not, and this measurement method(avometer connect to the RIN1 and GND) is right or not? thanks.
The RS-232 specification requires the receiver's input impedance to be 5 kΩ ± 2kΩ. This is also what the datasheet guarantees in section 6.8.
Hi Zhang,
Your measurement setup is correct, and 5.2K Ohms will not affect the system operation. That resistor value is within datasheet specification as Clemens highlights.
Best,
Ethan