Expansion of ADC channels for LPC2114 ?

Started by "kanishka.shah" April 9, 2009
Hey...Friends...

I would like to know a compatible IC that can be multiplexed with the existing ADC channel. Basically LPC2114 had just 4 ADC channels... I would like to extend this to 8 channels in total....I am planning to use CD4067 ADC Multiplexer.... is it a rite choice??..considering it has a measurement range of 0-5V and lpc2114 has measuring range of 0-3V...or is their a better replacement available?

Thank You

An Engineer's Guide to the LPC2100 Series

Hello,

Am Donnerstag, 9. April 2009 schrieb kanishka.shah:
> Hey...Friends...
>
> I would like to know a compatible IC that can be multiplexed with the
> existing ADC channel. Basically LPC2114 had just 4 ADC channels... I would
> like to extend this to 8 channels in total....I am planning to use CD4067
> ADC Multiplexer.... is it a rite choice??..considering it has a measurement
> range of 0-5V and lpc2114 has measuring range of 0-3V...or is their a
> better replacement available?
>
> Thank You

well, almost any analogue mutliplexer will do. But it has some drawbacks. They
simply dont have 0 ohms internal resistance, which means that you loose
accuracy on these extra-multiplexed ADC channels. Then you need a rather good
layout as to not inject noise in the lines.

I would recommend that you use a suitable external ADC. The TLC2543 from Texas
Instruments is a nice chip. It has 11 channels with 10 bit resolution each,
you can use an external reference, and it is connected through a simple
serial interface to the C. Oh, and thery are cheap too. I use them quite
often.

Greetings,

Chris