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Max pin output current limit

javida14
Associate II
Posted on December 12, 2006 at 12:08

Max pin output current limit

3 REPLIES 3
javida14
Associate II
Posted on December 11, 2006 at 21:13

The STR730 part has a source/sink capability of 2ma. if an output pin is in a logic high state and the pin is accidently shorted to ground will this destroy the pin or is the output internally limit to 2ma?

Javi

kleshov
Associate II
Posted on December 12, 2006 at 02:59

There is no internal current limiting. Current will be limited by ON-resistance of the open transistor. Based on the 2mA figure, short circuit current could be around 10mA. It is unlikely to destroy the I/O pin, but you shouldn't take the risk.

Regards,

- mike

javida14
Associate II
Posted on December 12, 2006 at 12:08

Thanks Mike,

The position of a rotary switch is being determine by connecting 8 outputs to the switch and the wiper to an input pin. A zero in a pattern of ones is being walk to determine the switch position. Just wandering if an IC buffer should be used in the outputs or not in case of a potential short in the external logic just to protect the uP.

Javi