I'm looking for a cheap and easy way to monitor temperatures and came across the Microchip EMC1403 which interfaces to general purpose diodes (or transistors with their base tied to collector/emitter respectively).
This fits my application quite nicely as the sensing points are at close distance but outside the PCB and only two wires are needed per sensor. Also, I expect leaded transistor packages (such as TO-126) to be resonably easy to handle and thermally bondable to the components to be monitored.
However, the datasheet does not go into much detail on which diodes/transitors are suitable and only mentions 2N3904 NPN or 2N3906 PNP general purpose transistors.
I wonder whether there are any specific characteristics that make up a good temperature-sensing transistor/diodes? I'm especially interested in higher-power devices because they come in cases which I expect to give better thermal-bonding.
Is there a reason for using transistors instead of simple diodes?