Hello team,
What is is the meaning of "Iload=100µA" in table 6?
Is the test circuit shown in Figure 20, with RL=1.35kohms used for this characterization?
Best regards.
Sylvain
Hello Thomas,
As the solution will be implemented in a design, I need an "official answer" from NXP.
The answer “I don't think so” is not safe from my point of view :-). An answer starting with “yes/no 100µA is a strict requirement” will be appreciated.
Regards
Hello Sylvain,
I do not think that 100μA is a strict requirement. Please try increasing the pull-up resistor on Port A to reduce the current and check if your VOL improves while keeping rise times within acceptable limits for your application.
BRs, Tomas
Hello,
I need some recommandations about Pullup on port A:
In paragraph 6.4.1.2, it's written that he pull-up resistor on the A side of the PCA9509P should be chosen to provide at least 100 μA of pull-up current.
Is-it mandatory to respect this condition?
In my application the VIL of of the master is 0.3XVCC where as the VOL (side A)of PCA9509P is 0.25VCCA (maximum value).
The power supply is 1.8V. so VIL(min)=0.3*1.8=0.54V and VOL(max)@100µA=0.25*1.8 =0.45V
The margin is : VIL(min)-VOL(max)= 0.54-0.45=0.09V.
This margin is very small, so I think that if I reduce current in port A, the VOL of Port A will be also reduced and the margin will increased. isn't it?
Sylvain
Hello Sylvain,
The PCA9509P is relatively old device and I did not find the relevant test details/results.
However, I assume that the "Iload = 100µA" in Table 6 specifies the test condition under which the VOL on Port A was characterized. When the device is driving the output low, it must maintain the VOL value while sinking a current of 100µA.
I do not think the circuit in Figure 20 was used directly for the VOL test in Table 6. The load current would be in mA range which significantly exceeds the 100µA condition specified for VOL characterization.
BRs, Tomas