Cheap and good way to feed 12v digital input

[Grumpy_Mike]

Actually I am not using it to trigger any arduino pin..

So what are you using it for?

[dlloyd]

Cheap, good and small:
SOT-89 (7805): 1.6mm x 4.6mm, area 7.36mm²,
SOT-416 (DTC114W): 1.7mm x 0.9mm, area 1.53mm², $0.20 each
I/O Connections: V_IN 0-30V, OUT (inverted) connected to PIC input with Pull-up enabled.

[nemo4all]

Actually I am not using it to trigger any arduino pin..

So what are you using it for?

I have mentioned it on my previous post. I am actually using it to trigger a SMD 8 Pin PIC Microcontoller..

The main target is to make the PCB as tiny as possible and making it cheap retaining the quality, as it will be mass produced..

[nemo4all]

Cheap, good and small:
SOT-89 (7805): 1.6mm x 4.6mm, area 7.36mm²,
SOT-416 (DTC114W): 1.7mm x 0.9mm, area 1.53mm², $0.20 each
I/O Connections: V_IN 0-30V, OUT (inverted) connected to PIC input with Pull-up enabled.

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..

[dlloyd]

Hint:
The 7805 has 3 terminals (INPUT, OUTPUT, GND).
The DTC114W has 3 terminals (IN, OUT, GND).

[Grumpy_Mike]

I am actually using it to trigger a SMD 8 Pin PIC Microcontoller..

What does that mean?
By trigger do you mean turn on, like applying power controlled by something else?

That sounds like an even worse idea.

[rmetzner49]

It's actually quite novel.  He connects the GND to ground, obviously, the OUT to the input pin on his Arduino, and the IN of the regulator to his switch or whatever his 12V signal is.  The 7805's output will be 5V with anything from about 7V to 30V on its input.

Not how the manufacturer envisioned its use, but should work just fine.

[dlloyd]

Not how the manufacturer envisioned its use, but should work just fine.

Hmm...no capacitors.

Here's what the Society of Robots has to say about that.

[JimboZA]

Here's what the Society of Robots has to say about that.

Bit misleading: It's no more the Society of Robots saying anything than Messrs Arduino saying anything in this public forum, is it? (However correct the individual member's views may be....)

That said, not one of the many schematics in the 7805 datasheet lacks caps.

[cjdelphi]

The caps would be very bad for serial communication... the 7805 will work up to a certain frequency but then it simply can't switch between 0 and 5v fast enough killing the serial data...

Change the 2 zener resistors for 10k to keep the current down.

[CrossRoads]

So what's the argument against using simple resistor divider with a zener just in case the input exceeds 16V?

[dlloyd]

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 5.5¢ 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)

[nemo4all]

I am actually using it to trigger a SMD 8 Pin PIC Microcontoller..

What does that mean?
By trigger do you mean turn on, like applying power controlled by something else?

That sounds like an even worse idea.

I actually meant that I am giving just and ON / OFF signal to the digital input of a PIC and the controls a condition..
I ON / OFF switching is not at all fast..

[nemo4all]

So what's the argument against using simple resistor divider with a zener just in case the input exceeds 16V?

There is no argument at all..

The issue is the space in the PCB. I have to fit components in a very tiny place, so lesser components, easier for me..

[CrossRoads]

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