I plan to connect VccB to a 3.3V power source. There are instances where a 5.5V output device will be supplying the inputs to port B. This creates an overdriven input on port B (since VccB is connected to a 3.3V source). The data sheet does not supply a value for Vih (max) for PortB inputs. Vi is specified in "Recommended operating conditions" as 5.5V max. So, the question is: Are the IO ports (port b in particular) considered as inputs that are capable of being driven to 5.5V when VccB is 3.3V? thanks
Please see datasheet page18 -Architecture of NTB0104 I/O cell,you can see the A/B is the push-pull architecture and the provide supply is from VCCA/VCCB.
So I think that If you fixed the VCCB as 3.3V input so it can only drive 3.3V.
Thank you for the response. My concern is not with the output voltage level on port B (I agree it will only drive to 3.3V). I am worried about overdriving Port B inputs and damaging the device. VccB will be 3.3V. There will be an external device with 5.5V outputs connected to the inputs on port B. Is the NTB0104 specified to operate in this manner? The data sheet makes it appear as it is ok. I want to confirm.
Your response is confusing me. VccB is connected to a 3.3VDC power supply. I don't know what you mean by "a 5.5V overlay this B ports". I also don't know what you mean by "Electrical appliances". I will be looking for alternatives in this case.
