Homebrew PCBs

--- In Homebrew_PCBs@yahoogroups.com, DJ Delorie <dj@...> wrote:
>
> 
> Steve Greenfield <alienrelics@...> writes:
> > AD595AQ Thermocouple amplifier, laser trimmed to match K type but can be recalibrated for other thermocouples. 10mV/C
> > <http://www.analog.com/en/temperature-sensing-and-thermal-management/digital-temperature-sensors/ad595/products/product.html>
> > 
> > $11.76 each from Digikey.
> 
> Alternatively, MAX6675ISA+ thermocouple to SPI chip, also K, $14 at
> digikey.  Outputs absolute degrees C (has its own internal cold
> junction compensator).  I used one of these to convert my laminator to
> digital, the hookup was trivial as was talking to it.
> 
> A few extra dollars for the convenience seemed to be worth it, no need
> to add any analog parts or rely on an MCU's internal ADC.
> 
> http://datasheets.maxim-ic.com/en/ds/MAX6675.pdf

The AD595AQ has internal cold junction compensation, too. And is laser trimmed for K junction to 1C accuracy, with J junction in the AD594, and either can have external resistors added to either trim closer, or change to work with the other junction. I'm not too worried about relying on a PIC's ADC.

But thanks for the tip. I see it has a 12 bit ADC.

Steve Greenfield