ISO1430: Drive Input and Receiver Output pin capacitance

Alfredo Sandoval

Part Number: ISO1430

Hi, I'm having trouble finding the pin capacitance of the driver input, receiver output and receiver/driver enable pins in the datasheet. Can someone help me find that information?

The MCU we are using cannot drive the driver input pin at rates higher than 1Mbaud. The line appears to have excess capacitive loading - see the purple waveform in the attached image.

over 2 years ago

+1 Alfred Chong over 2 years ago

TI__Expert 3482 points

Hi Alfredo,

Thank you for reaching out to us!

The pin capacitance is listed below.

D = 3pF
R = 5pF
DE = 3pF
RE_BAR = 3pF

The pin D capacitance is negligibly low, and it does not contribute excessive load to the MCU drive.

I suggest looking into these areas to identify the root cause.

1. Is the trace between the MCU driver and pin D relatively long?
2. Does it have a series resistor in the path?
3. Any additional loading along this path?

Regards,

Alfred

0 Alfredo Sandoval over 2 years ago in reply to Alfred Chong

Prodigy 10 points

Thanks Alfred! The issue was due to capacitance of a FET that was tied onto the Drive pin line.

0 Alfred Chong over 2 years ago in reply to Alfredo Sandoval

TI__Expert 3482 points

Hi Alfredo,

I'm glad that you found the root cause.

Regards,

Alfred

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ISO1430: Drive Input and Receiver Output pin capacitance