Go Down

Topic: Cheap and good way to feed 12v digital input (Read 6536 times) previous topic - next topic

Joy

#30
Oct 19, 2014, 09:09 am Last Edit: Oct 19, 2014, 09:11 am by Joy Reason: 1

Two 0402 resistors and an 0603 zener, that's pretty small.
What quantities are you making these in?


yes I know, that these 3 components are really small.. But 3 different footprints will require lil more space.. And the 7805 SOT-89 package is taking lesser space..

Making them in 1000+ quantities.. on homemade PCBs. So will not be able to make very thin tracks... If I could then would have been able to fit the two 0402 resistor and a 0603 zenner in a very tiny space..

Joy


Quote
I am unable to make out how will it work..
I went through the datasheet too, bu cant make out..It would be kind of you, if you can elaborate please..


Just 2 parts, smaller footprint, low cost 5.5ยข per PCB (qty 1000)
High performance: 0-30V Input, Max 250MHz transistor frequency, Inverted 0-5V output

DTC114W Digi-Key $0.04844 each (qty 1000)
ERJ-2RKF2201X Digi-Key $0.00699 each (qty 1000)




Will this work too..??
http://in.element14.com/on-semiconductor/mmun2215lt1g/transistor-digital-sot-23/dp/9556680?whydiditmatch=rel_3&matchedProduct=dtc114&matchedProduct=dtc114&whydiditmatch=rel_3

CrossRoads

1000+ & homemade PCBs? You are a glutton for punishment!
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

CrossRoads

Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

Joy


1000+ & homemade PCBs? You are a glutton for punishment!

hahaha..

please don't get me wrong..

The reason I use the homemade PCB is that there is no good estimation that how many will sell off..
Hence the keep making these 50 - 70 at a time..
It just takes half an hour to make the PCB...

And profit margins form the product is very very low..

Joy


cjdelphi




What's with the second resistor on the npn's base? (pull down? It's not a fet, it's not biasing?)

cjdelphi


dlloyd

#38
Oct 19, 2014, 03:36 pm Last Edit: Oct 19, 2014, 05:45 pm by dlloyd Reason: 1
Quote
Will this work too..??
http://in.element14.com/on-semiconductor/mmun2215lt1g/transistor-digital-sot-23/dp/9556680?whydiditmatch=rel_3&matchedProduct=dtc114&matchedProduct=dtc114&whydiditmatch=rel_3


Yes, this type will also work.

Note that the transistor begins to turn at about VBE = 0.5V.
The MUN2215 will turn on when the input is at 0.5V.
The DTC114W will turn on when the input is at 1.5V, providing higher noise immunity.

Go Up