30A continuous wouldn't be a sensible application for these sensors.
ok had another look at the data sheet i cant find any mention of heatsinking,i really dont understand where this heat would be coming from in the first place, the current passes between IP+ (pins 1 and 2) and IP- (pins 3 and 4) the resistance is 0.3 ohms how can this generate any heat?
Hmm... well since this is a +/-30A sensor I do assume it is safe to run 30A through the chip... But for my application, the current actually won't go over 5A, so it is not really a concern to me. The thing I am worry about is the voltage cause it is going to be constantly around 100V.
Quote from: jonisonvespa on Feb 10, 2013, 12:42 pmok had another look at the data sheet i cant find any mention of heatsinking,i really dont understand where this heat would be coming from in the first place, the current passes between IP+ (pins 1 and 2) and IP- (pins 3 and 4) the resistance is 0.3 ohms how can this generate any heat? Can't be .3 ohms and still rated for 30amps. Amps squared X R loss would blow the whole module up.Lefty
What resistance does your meter read:(a) when you press the probes directly on to the leads of the chip;(b) when you press the probes against each other?
All I will point out is the size of the eval pcb heat sink vs what the commercial resellers typically design and sell. The datasheet mentions a typical internal resistance of 1.2 mOhm for the acs712 and a 5x over current survival. The datasheet also mentions a atypical 2oz copper thickness for the pcb used on the eval board. The FAQ also shows die temperatures assuming optimal conditions (ie eval board) reaching 165 C at 20amps in hot ambient conditions. I expected my device to potentially get hot inside as it did not feature active convection and the enclosure is small. So, by all means go and use this sensor but between the relatively high error and the heat issues, if was not suitable for me. For those measuring short impulse loads in particular, this chip family features very attractive attributes like small size and relatively low cost. I went for the LTSR series from LEM instead. It's leads are significantly beefier, you get a reference voltage for differential measurements, etc.
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