Hello
I am using ADS8327IBPW with Vref LM285 to read the temperture from the TMP26 .
Could you please check my schematic.
Vref=2.5V
VA+ = 3.3V
VBD = 2.5V
IN+ = 0.7V to 1.2V
IN- = GND
This thread has been locked.
If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.
Hello
I am using ADS8327IBPW with Vref LM285 to read the temperture from the TMP26 .
Could you please check my schematic.
Vref=2.5V
VA+ = 3.3V
VBD = 2.5V
IN+ = 0.7V to 1.2V
IN- = GND
Hello Roi,
Your schematic looks correct and the supply and reference voltages are correct. I also checked the pinout for the ADS8327, TMP36, and LM285 and everything is also correct.
Please note that driving the ADC input through a voltage divider from the TMP36 will reduce the maximum sample rate. With the values chosen, the maximum data rate should be 10ksps or lower for proper settling.
Regards,
Keith Nicholas
Precision ADC Applications
Hello Roi,
One other comment; I suggest powering the reference from the same supply voltage as the +VA supply on the ADS8327 to avoid any power-up issues if the reference ramps up before the the analog supply.
In the below diagram, power the reference from TEMP_POWER, and decrease R7222 to around 10kohm.
Regards,
Keith
Hello Roi,
Yes, as long as R7222 is reduced in value to supply enough current. That is why I suggested using a value of R7222 equal to 10kohm. The resistor network that sets the output voltage will use about 10uA, and the ADS8327 should have about 10uA available, leaving 50uA of bias current for the LM285.
Please keep in mind that the maximum sample rate of the ADS8327 needs to be 10ksps or lower in order for the input and the reference to settle.
Regards,
Keith Nicholas
Precision ADC Applications
Hello Roi,
Yes, VBD only powers the IO interface. +VA can power-up after VBD.
Regards,
Keith