Description
Yes, this is acceptable, provided that the PCI clamping diode is disabled.
Consider the case when the pullup resistor is 10K. When the output is being driven LOW, the total current flow through the device is approximately 0.5 mA (5 V/10K). When the output is being driven HIGH, the p-channel metal-oxide semiconductor would have 3.3 V on the source. Its drain is connected to the external 5 V supply through a 10K resistor. Thus, the total current flowing from the drain to the source would be approximately 0.17 mA (a reliabile level).
When the pin is being used in input mode, a 5-V input will not damage the device since it is 5-V-tolerant.