Switching transistor & IC current

[ayashisunyday]

Gentlemen,

I'm working on a small PCB that will be made with SMTs. Due to the components caracteristics (most of them will fry with only a few miliAmp) I'm trying to evaluate the good ones to pick and the correct design to stay green.

I've assessed everything except the current that will flow between my transistor C/E pins when the switch is closed.

Basically this transistor is used to ground C1 and clear it. The circuit is a peak & hold detector.

I've attached the design (board is powed in 0 / +5V):



The transistor is a MMBT2222AWT1G. The datasheet says "Collector Current − Continuous, ICmax = 600mAdc" does that means that it can handles up to 600mA ? Simulation says that the current can reach 33mA.

Thanks for your help!
Aya.

 

[crutschow]

Don't see how you get 33mA through the 1k ohm resistor since the maximum voltage on C1 is less than 5V.

Yes, the 2222A transistor collector can carry up to 600mA collector current.

 

[ayashisunyday]

Should be a simulation issue. I didn't understand it as well ;o)

Many thanks for your answer!
Aya.