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74LCV4245 Power Dissipation

Frank Pesta
Prodigy 15 points
Other Parts Discussed in Thread: SN74LVC4245A

I'm testing a SN74LVC4245A for a circuit I'm designing where I need to pull roughly 24 mA from each 5V output. After looking over the DS a few times, I have not been able to find power dissipation ratings for this chip. Is there a set dissipation rating for this chip?

  • 0
    TI__Expert 6380 points

    The spec is a littel vague - it is rated to 85C with all outputs at 24ma.

    That being said, you can calculate what the part is disspating as a static load by taking (VCCa-VOHmin)*Iout for each pin.

    For 4.5 and 5.5 Vcca the fdrop is specified at roughly 0.8V  so  0.8V*24ma = 19.2mW per pin

    For 8 pin 19.2mW*8= 153mW

    The temperature rise of the package will be this mW* qJA (C/W)  so for a DW package 153mW*46 C/W = 7 degree rise.