High side switching.

[Jim]

Hi,

I have a radio module that I need to high side switch. (10mA)

Any methods I have used so far have drawn alot of current in their own right
(2mA).

Can anyone offer suggestions or tips for high side switching this module?

I was hoping to use 2uA in the switch. The unit runs from 3v supply.

It needs to be a solid state solution.

Thanks

Jim

 

[Fritz Schlunder]

"Jim" <jim@SPAMTRAPprintedcircuitboards.net.invalid> wrote in message
news:bvldlc$3lj$1@titan.btinternet.com...

Hi,

I have a radio module that I need to high side switch. (10mA)

Any methods I have used so far have drawn alot of current in their own
right
(2mA).

Can anyone offer suggestions or tips for high side switching this module?

I was hoping to use 2uA in the switch. The unit runs from 3v supply.

It needs to be a solid state solution.

Thanks

Jim

How about using a low threshold voltage P-channel MOSFET. Sounds like the
perfect type of part to meet your requirements. Any product of a great
number would surely work, but for one possible example perhaps the IRLML6402
(Digikey carries them):

http://www.irf.com/product-info/datasheets/data/irlml6402.pdf

With this kind of voltage level and current demand you could also probably
use 74AC type logic gates or suitably beefy tiny logic parts.

 

[Thomas C. Sefranek]

"Jim" <jim@SPAMTRAPprintedcircuitboards.net.invalid> wrote in message
news:bvldlc$3lj$1@titan.btinternet.com...

Hi,

I have a radio module that I need to high side switch. (10mA)

Any methods I have used so far have drawn alot of current in their own
right
(2mA).

Can anyone offer suggestions or tips for high side switching this module?

I was hoping to use 2uA in the switch. The unit runs from 3v supply.

It needs to be a solid state solution.

Use a PNP (2N3906) as the series switch, driven by an NPN (2N3904) to
ground.
A resistor (24K) in series with the bases is indicated. This will have a
burden of .1uA
plus the base drive for the NPN.

Thanks

Jim

--
*
| __O Thomas C. Sefranek WA1RHP@ARRL.net
|_-\<,_ Amateur Radio Operator: WA1RHP
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