Part Number: LM26
Greetings,
We are using an LM26 in our design as an overtemperature sensor. We would like to be able to latch the output low for as long as power is supplied to the circuit once the threshold is tripped, and not have it go high again after the configured hysteresis condition is met.
Looking in the datasheet on page 9, I see in section 8.4.1 that it is encouraged for PCB testing to sink the Vtemp pin to ground in order to force the main OS output low. Will the part be harmed in performing this action many times? My idea is to wire a cheap PNP transistor between the Vtemp line and ground with the base connected to the OS output since the datasheet makes it seem as though Vtemp current is internally limited. Should this be reliable for long-term usage?
Below is the circuit. I suppose my biggest concern with this is that the Vtemp pin will still see a max of 0.4V (from the datasheet - OS logic low voltage) plus Vbe of the transistor, which I would assume will limit what our effective max trip temperature can be for this circuit to still function as intended. We can always swap for a FET as well if this proves to be a problem, but the PNP here will be cheaper.
Also will the current out of the Vtemp pin be the 1.5mA overdrive current mentioned in section 8.4.1 if it is sunk to ground externally like in the circuit below?
Thank you,
Carter
