# maximum input current of an integrated circuit

#### ouafae

Joined Jun 11, 2019
52
hi

I have a question about the power supply of an integrated circuit. in the data sheet I found that the max, min, and typical value of the voltage but I found nothing about the current. in this case how can I know the max current that I should not exceed it?

#### ouafae

Joined Jun 11, 2019
52
can I calculate the maximum input current from the maximum power dissipated?

#### DickCappels

Joined Aug 21, 2008
9,296
Somewhere in the datasheet there is a power supply current specification. In the case of circuits like amplifiers and voltage regulators (which include amplifiers) the current of the device being driven (load current) contributes to the current into the device and therefore affects the power dissipation.

If you are thinking about a particular integrated circuit and tell us what it is we can probably give you more specific help.

#### ouafae

Joined Jun 11, 2019
52

#### bwilliams60

Joined Nov 18, 2012
1,433
On page 5 down at the bottom where it shows supply voltage, it shows your maximum current at 15v and 5v depending on your 555 timer type.

#### ouafae

Joined Jun 11, 2019
52

#### DickCappels

Joined Aug 21, 2008
9,296
If you do not put a significant load on the output of the NE555 then the output current does not contribute significantly to the power dissipation.
With no load on the output this telles you the current drain.

#### ouafae

Joined Jun 11, 2019
52

#### SamR

Joined Mar 19, 2019
4,397
Which is one of the reasons to use a switching transistor on the 555 output for large loads.

#### Audioguru

Joined Dec 20, 2007
11,248
The datasheet for an old NE555 does not show its supply current surge each time its output switches due to its old TTL type of push-pull output stage that has a shoot-though current of almost 400mA!

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#### SamR

Joined Mar 19, 2019
4,397
Ouch! At least the duration is short but??? How do TTL stand up to spikes like that? The ICM7555 is supposed to be MAX 600mA @ 18V. Bought some but haven't played with them as yet. That almost gets you to the 2n2222 800mA if so.

#### DickCappels

Joined Aug 21, 2008
9,296
I think that if you read back far enough into history, this is a fairly common switching spike. A small high Q capacitor is enough to take care of the glicth on the power supply.

#### SamR

Joined Mar 19, 2019
4,397
I get suppressing it with a cap, but can the TTL ride through it without suppression? How vulnerable are TTLs??? IE is the cap needed?

#### SamR

Joined Mar 19, 2019
4,397
And the answer is one 0.1 - 0.01uF cap for up to 4 TTL chips required to quell spiking. According to Don Lancaster at least.