How can I integrate analog components for a small keyboard device?

[AoiPhysF]

Hello everybody,

I'm trying to do some kind of keyboard device which has like 12-15 digital inputs and outputs to a serial USB port. Because other similar circuits I've seen I know I need a microcontroller and some capacitors. The problem is, my device has to be very small and I can't put capacitors and a big IC all over the place. I guess the best option would be some Analog/digital IC with everything integrated inside, but I don't know if this is even possible. Ideally I would like just an IC of that kind, the smallest possible one, and just circuits for the rest (and the buttons of course). SMD capacitors are also an option but I would prefere everything inside de IC.

Is this even possible? If someone can make some clarifications I would be happy

Thanks

 

[berkeman]

Hello everybody,

I'm trying to do some kind of keyboard device which has like 12-15 digital inputs and outputs to a serial USB port. Because other similar circuits I've seen I know I need a microcontroller and some capacitors. The problem is, my device has to be very small and I can't put capacitors and a big IC all over the place. I guess the best option would be some Analog/digital IC with everything integrated inside, but I don't know if this is even possible. Ideally I would like just an IC of that kind, the smallest possible one, and just circuits for the rest (and the buttons of course). SMD capacitors are also an option but I would prefere everything inside de IC.

Is this even possible? If someone can make some clarifications I would be happy

Thanks

Welcome to the PF.

No, you will not integrate much capacitance inside of an IC. But you also should not need much in the way of capacitance on a small keyboard device.

But you also mentioned "inputs and outputs" -- what exactly would this device do?

It will be hard to get much simpler than to use a PIC or other microcontroller (uC) that has USB interface capability...

 

[AoiPhysF]

Sorry, I said it wrong, with "outputs" I meant with USB capability as you said. The problem is that I have opened various keyboards/controllers and all of them seem to have electrolityc capacitors and also a ceramic one, they also have surface mounted ones at the same time though, that made me think that perhaps they are needed in some way. I don't know if all of them could be replaced by surface mounted ones instead, probably they do. The electrolityc ones are 1uF 50V.

If you say that for a keyboard you could put them all inside an IC I understand that it could be done also with SMD so.. that would be enough for this. I realize now that the idea about integrating all this in just one IC is probably crazy, but I have heard that there are somewhat programmable mixed IC's.