Part Number: P82B96
Hello,
in our usecase the P82B96 is used as in the blockdiagram showed: 
In regard to the EMC Tests the Pull Ups on the 5V Vcc is getting better results with 470 Ohm instead of 4k7 Ohm.
The recommended current for the Sx/Sy is defiend as:
But also has a "Dynamic Output capability" of 18mA which I provide.
So is a Pull up with 470 Ohm acceptable?
Thanks for the respond!
Hi its me again,
and in addition to that the datasheet says: 
What does that mean in context? It appears to me that i can not connect Sx pins to any devise...
I'm sure I've misunderstood something here.
Thank you!
Micha,
So is a Pull up with 470 Ohm acceptable?
IOL can be calculated as follows.
IOL = (5V - VOL) / 470 ohm
This would tell you how much current is being sank by the P82B96 statically. If this number is > 3mA when VOL = 0.4V, then this is technically too strong of a pull-up on the Sx/Sy pins.
On the buffered bus (Tx/Ty) pins, IOL can be upwards of 30mA. So stronger pull-ups such as 470ohm on the buffered bus granted the drivers pull <30mA statically, then 470ohm is okay. 5.5V / 470 ohm = 11.7 mA ~, This pull-up current is easy to sink through the buffered side drivers of the P82B96. This type of current may not be suitable on the Sx/Sy pins however, since they are rated for 3 mA.
What does that mean in context? It appears to me that i can not connect Sx pins to any devise...
I believe this is referring to the direction control of the device. P82B96 outputs a voltage on Sx/Sy pins that is higher than its input threshold on the Sx/Sy pins. See datasheet:
This is to help with direction control. Driving a signal from Rx/Ry to Sx/Sy outputs a VOL voltage ~0.88V. When driving the other direction from Sx/Sy, input must be ~0.65V threshold to drive a LOW in the opposite direction.
If an engineer connects the Sx/Sy pins of two P82B96's, direction cannot work. A LOW signal would be unable to pass since the P82B96 cannot output an Sx/Sy VOL = 0.65V by itself.
Regards,
Tyler
Hi Micha,
I believe the 18mA is referring to the transition strength. The current sink capability when transitioning from a high logic to a low logic signal. I think this is reference to the slew rate. The static current is can sustain (i.e. if Rx/Ry = 0V) Sx/Sy is rated to sink 3mA @ 0.4V .
IIOS could be as weak as 7mA, or typical 18mA current sink strength. There is no maximum rating here.
If we want to look at the maximum sink current before damage is possible, we can look at the absolute maximum ratings.
The recommended operating conditions in section 7.3 guarantee the electrical characteristics in section 7.5. If the user were to have a really strong pull-up resistor on Tx/Ty for example that would pull 100mA of current, this would be outside recommended operating conditions which would then no longer guarantee the electrical characteristics in section 7.5.
However, we can guarantee by the datasheet that sinking 100mA of current through Tx/Ty would not damage the device due to the absolute maximum ratings in the datasheet. Functionality may not be normal, but we can guarantee device was not damaged in this specific case.
Regards,
Tyler
