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Allegro ACS724 50 amps current sensor - can it withstand 3 W thermal power ?

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anotherbrick

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Hello dear forum ,

I am an electronics engineer designing a 24 V DC motor driver circuit

I want measure the motor current with

ACS724LLCTR-50AB-T

However datasheet says it has 1.2 miliOhm conductor resistance

If I pass 50 amper through this ACS724

The thermal power will be 1.2miliohm *50*50 = 3W

My question is this ; this IC is very tiny

**broken link removed**

Can this sensor IC withstand this amount of thermal power ? if yes how long ?

anybody wo used this sensor before ?

Thank you
 

I have already used the ACS713 and ACS 712 with 30A continuously with no problems.


For ACS724 considering the mounting recommendations:
"Mounted on the Allegro 85-0740 evaluation board with 800 mm2 of 4 oz. copper on each side, connected to pins 1
and 2, and to pins 3 and 4, with thermal vias connecting the layers. Performance values include the power consumed by
the PCB."
It will have a 23 ºC/W thermal resistance and 69ºC temperature increase for 3W. It seem to be ok if the ambient temperature is below 40 or 50ºC.
 
The thermal power will be 1.2miliohm *50*50 = 3W
Click to expand...

Hi
You sure your current is exact DC ?

You said this :


I am an electronics engineer designing a 24 V DC motor driver circuit
Click to expand...

So is that mean that you're controlling the DC voltage using PWM ? if so , you must consider average of the current hence dissipation is much lower .
Nevertheless , it depends on ambient temperature ! have a look through the datasheet !

Best Wishes
Goldsmith
 
Datasheet pg 3 does say 23degc/watt for rthJA….but that it with an enormous amount of PCB copper and thermal via’ing, so if you cant replicate that, then there is no way a soic8 can do 3W.

**broken link removed**
 
If you cant follow the 800mm² recommendation you can try to use a small heatsink on the IC.
 
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