I have a pulse that is approx 5ma at 3.3V
This needs to drive a device that needs 50-100ma at 3.3V
I can supply 3.3V or 5A for operational voltage.

any idea what IC I could use for this ?

I know I can build a current gain circuit from a npn transistor, but I am hoping that a low power current amp is available as a standalone IC.

 

An IC vs one logic-level MOSFET?

Ken

 

Just realized there are logic-level MOSFETs. Would you advise on the suitability of a BJT or MOSFET for driving 100ma approx. ?
I also realized that a MOSFET does not need a bias resistor at these low currents.
Only gotcha may be that I am using 3.3V not 5V

 

Try an STP22NF03L from DIGIKEY...$1.10. It should meet your 3v logic switching and your load requirements. Down side may be that it's in a TO-220 case. Is that a problem?

Ken

 

Try an STP22NF03L from DIGIKEY...$1.10. It should meet your 3v logic switching and your load requirements. Down side may be that it's in a TO-220 case. Is that a problem?

Ken

That part is not spec'ed for Vgs<5V.
Fairchild has a boatload of logic-level MOSFETs spec'ed for Vgs=2.5V. Other companies also have them.

 

To-220 is actually good. I hate soldering SMDs. But it turned out my project had a problem with the clock frequency. So maybe I wont need this at all.