Hi all,
I'm doing a project for temp. monitoring using LM35DZ the supply is 5V I don't know what's the sutable R between Vout & ground to aviod self heating because we can't get Vout with out this R also i need to adesign to get the range of Vout be from 01 to 0.9 using opamp or anything else so please could anyone help me
PLZ, Best regards
Maybe you would be way better off trying something digital. A part like the TMP100 from TI is an easy piece of cake to use with its I2C interface bus, runs on miniscule current, is rather easy to make work as a temp monitor.
- mkaras
According to the data sheet, you don't need any resistance between Vout and ground.
If you are loading Vout with more than 50pF of capacitance, you wll want 2k in series with the output to stop it oscillating (Fig.3 on page
7 of the data sheet), or 75R is series with 1uF to ground to do the same job (Fig. 4 on page 7).Neither arrangement adds to the self-heating.
Your request for a circuit to "get the range of Vout to be from 0.1 to
0.9" isa little unspecific.Do you want 0.1V to 0.9V? If so, what temperature do you want to correspond to 0.1V out of your op amp, and what temperature to 0.9V? The LM35 is perfectly inflexible in generating a specific output voltage of 10mV per degree C (+/-5mV 2C on up - that is it starts at
20mV+/-5mV at 2C, and goes up 1.0V+/-15mV at 100C.-- Bill Sloman, Nijmegen
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