Hi team,
The board including the following circuits works normally but sometimes Problems may occur on. Please tell me how to use the device.
■Current usage
As shown in the figure below, the output signal from BCT245 (TTL) is connected to SN74LVC16T245DL via the terminating resistor. SN74LVC16T245DL's PortA power supply is connected to 3.3V and Port B power supply is connected to 5V. When the signal voltage of the SN74LVC16T245DL input was measured, it was 3.2V at High and 0.4V at Low. However, VIH of SN74LVC16T245DL does not meet the specifications at 3.5V. Is it OK to think that this may cause a malfunction?
■ Modification plan
I will change the PortB power supply from 5V to 3.3V. VIH=2V, VIL=0.8V, so I think it will operate correctly even with input signals H=3.2V and L=0.4V.
■Question
Is there any problem with the above improvement plan? Both PortA and PortB are 3.3V power supplies. Is there no problem?
Beat Regards,
Tom Liu
