The absolute maximum output current of NE555

user5316778

Other Parts Discussed in Thread: NE555

The absolute maximum output current of NE555 is discussed in the datasheet.

What is the absolute maximum output current? Which one may by occurred? NE555 may be damage if it operates over its' absolute maximum output current 225mA or the output current can be clamped to its' absolute maximum output current 225mA.

If the capacitor is assumed as the NE555's load, what the current waveform can be observed? High pulse current or the current is clamped to its' absolute maximum output current 225mA?

over 5 years ago

0 Ron Michallick over 5 years ago

TI__Guru**** 164456 points

Hello User,

Could a series resistor be added between output and capacitive load. Set R > VCC / 225mA

The NE555 does not have an output current limit circuit

0 Ron Michallick over 5 years ago in reply to Ron Michallick

TI__Guru**** 164456 points

User,

What is the capacitance value and VCC voltage?

0 user5316778 over 5 years ago in reply to Ron Michallick

Intellectual 340 points

Very large capacitor is used to verify the maximum current of NE555 and VCC is 12V.

0 user5316778 over 5 years ago in reply to Ron Michallick

Intellectual 340 points

Very large capacitor is used to verify the maximum current of NE555 and VCC is 12V.

After the test, the peak current of output of NE555 is clamped to about 500mA (The current waveform is trapezoid, not current step-response of RC circuit) instead of much greater than 225mA.

0 Ron Michallick over 5 years ago in reply to user5316778

TI__Guru**** 164456 points

The output high drive is supported by an darlington emitter output so the high driver has very low impedance.

This chart only goes to 100mA , but it is clear that the lines are quite flat. (Low impedance)

Chart is VOUT-VCC vs IOUT

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The absolute maximum output current of NE555