LPC1549 Standard IO Pin Protection and Voltage Levels

jpacl — Tue, 01 Nov 2022 18:16:23 GMT

The datasheet states that a standard IO pin is 5V tolerant, when Vdd is above 2.4V. Can a standard IO pin be connected to a 5V voltage rail through a 3k resistor during power up, providing a 1.6mA current source?

Can a standard IO pin, configured as an input, be connected to 1.6V voltage source, placing the input into an indeterminate state, the logic state of the input would not be used in this case?

Can a standard IO pin, configured as an analog input, be connected to a 5V voltage rail through a 3k resistor indefinitely, providing a 1.6mA current source?

Re: LPC1549 Standard IO Pin Protection and Voltage Levels

ZhangJennie — Tue, 08 Nov 2022 05:55:19 GMT

Hi jpacl

>>The datasheet states that a standard IO pin is 5V tolerant, when Vdd is above 2.4V. Can a standard IO pin be connected to a 5V voltage rail through a 3k resistor during power up, providing a 1.6mA current source?
Can a standard IO pin, configured as an analog input, be connected to a 5V voltage rail through a 3k resistor indefinitely, providing a 1.6mA current source?

Answer: No. the max input leakage current is several uA, So it can't provide 1.6mA current. see below screenshot from Datasheet.

>>Can a standard IO pin, configured as an input, be connected to 1.6V voltage source, placing the input into an indeterminate state, the logic state of the input would not be used in this case?

Answer: No, 1.6V input is a indeterminate state, we can't use its logic state.

Thanks,

Jun Zhang

LPC MicrocontrollersのトピックLPC1549 Standard IO Pin Protection and Voltage Levels

LPC1549 Standard IO Pin Protection and Voltage Levels

Re: LPC1549 Standard IO Pin Protection and Voltage Levels