I want to know, if the output of a 555 Timer (e.g. NA555) is low level, high level or floating, if no positive supply is attached to the device. (only VCC is disconnected, all other pins stay connected)
Thomas,
The output characteristic is not guaranteed, but the output appears to a have a diode to VCC and ground.Therefore it is high impedance only in the range of +/-300mV.
Regards,Ron Michallick
Regards,Ronald MichallickLinear Applications
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Ron,
Where did you find a diagram depecting the output stage of the 555.
EDIT: Specifically, I mean a diagram of a TI/National CMOS-type 555
Thanks,
Jonathan
Jonathan,
I just applied voltage to the output pin with the other pins grounded on the bipolar NE555.
The CMOS 555 is called TLC555, I did not test this device.