SN74LVC1G08: the temperature and power consumption

dimitry chen

Expert 1145 points

Part Number: SN74LVC1G08

My desing is VCC=5V , and driving around 30mA (LED)

is that mean power consumption is 150mW , and DBV package will increase 206x0.15=30

thanks

over 7 years ago

0 Dylan Hubbard over 7 years ago

TI__Mastermind 46355 points

Hi Dimitry,

The device isn't consuming all that power it is delivering that 30 mA to the LED. Most of the power loss in the device comes from the output driver Ron. So the calculation would be (VCC-VOH)*30 mA. Your calculation of package temp increase is inaccurate as well. The thermal resistance values are used to figure out the junction temperature of the device. I am linking below an app note that covers this. To know the case temp, I'd recommend using a thermocouple.

www.ti.com/.../spra953c.pdf

0 dimitry chen over 7 years ago in reply to Dylan Hubbard

Expert 1145 points

HI
if I set vol to drive LED.

Iol = 30mA, Vol is around 0.55V,
so my power consumption is (5-0.55)*30mA ?

0 Dylan Hubbard over 7 years ago in reply to dimitry chen

TI__Mastermind 46355 points

Hi Dimitry,

In this instance it would be .55V*30mA. VOL comes from the voltage across the nMOS at the output.

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SN74LVC1G08: the temperature and power consumption