TLC2543 jumping all over the place

Hans

Hi all,

I'm having a little trouble with a TLC2543 connected to my 2SX.
Even if I have a rocksteady voltage applied to one of the input pins,
the readout is quite jittery. I have Ref- connected to GND, ref+ to +5V supply,
and a steady 2.5 volts applied to the input pin by way of a voltage divider
(two resistors). When I put a voltmeter on that same pin, it is steady as
a rock. Yet the readout (which should read 2048) jumps from roughly 2040 to
2060. Is this normal TLC2543 behaviour or am I suffering from excessive noise ?

I'm using it to read (amongst others) the voltage on a 28 V battery bank, but
I fail to get a steady readout this way.

Any help greatly appreciated,

Hans

Newzed

Put a 1.2K resistor in series with the sensing lead, and add a .1uf bypass cap to the ADC input pin.· The cap should be as close as possible to the ADC.· This will make it rock steady.

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Sid Weaver
NEW! 4 MB EEPROM

http://hometown.aol.com/newzed/page4.html
·

Hans

Thanks ! I'll try that tomorrow. Knew it had to be something like this.

Hans