SN74AUCH244: Asking for the SN74XXX series power consumption data information

Hello SHH,

Here are the thermals:

SN74AUCH244RGY:

SN74AVC4T245PWR:

SN74AVC4T774PWR:

SN74LVC1G00DCKR:

Now the thermals are a bit trickier to provide. In your question you have provided me with a method to calculate power consumption. However power consumption is heavily dependent on the frequency of operation.

There is static power consumption which is Ps = Vcc*Icc. Then there is dynamic power consumption which is a combination of the transient power (Pt), capacitative load power (Plc) and resistive load power (Plr). Your equation is only the combination of Ps + Plr. However the transient power Pt is much greater than the other two dynamic power consumption. 

You can calculate the

Pc = Cpd*(Vcc)^2*f + Icc*Vcc

Cpd = measure of the dynamic power a device requires (listed in the datasheet for each of those devices)

f = frequency of operation

Vcc and Icc can also be found in the datasheet

The Pd can be calculated based on the temperature data I have provided to you using the equation: 

Pmax(W) = (TJ(max)(°C) - TA(max)(°C)) / θJA(°C/W)

Pmax := maximum power consumption before thermal failure

TJ(max) := maximum junction temperature (150°C for standard logic devices, unless otherwise stated in the datasheet)

TA(max) := maximum ambient temperature of operation (system's maximum ambient operating temperature, rather than the device's maximum ambient operating temperature)

θJA := junction-to-ambient thermal resistance

Thanks!

-Karan

Hello SHH,

You can use the same CPD as the SN74AVC4T245. They should be similar as they are the same family. Please also note that the frequency is not from the datasheet, but the frequency at which the customer is operating the device.

Also note that I missed a variable in that equation:

Pc = Cpd*(Vcc)^2*f*Nsw + Icc*Vcc

Nsw: Number of switching channels. Since this is a 4 channel device and if all 4 bits are switching at the same time, this will increase the power consumption.

Thanks!
-Karan