SLVS714B February 2007 – June 2024 TPS2062-1 , TPS2065-1 , TPS2066-1
PRODUCTION DATA
Refer to the PDF data sheet for device specific package drawings
The low on-resistance on the N-channel MOSFET allows the small surface-mount packages to pass large currents. The thermal resistances of these packages are high compared to those of power packages; it is good design practice to check power dissipation and junction temperature. Begin by determining the rDS(on) of the N-channel MOSFET relative to the input voltage and operating temperature. As an initial estimate, use the highest operating ambient temperature of interest and read rDS(on) from Figure 5-9. Using this value, the power dissipation per switch can be calculated by:
PD = rDS(on) × I2
Multiply this number by the number of switches being used. This step renders the total power dissipation from the N-channel MOSFETs.
Finally, calculate the junction temperature:
TJ = PD ×RθJA + TA
Where:
TA= Ambient temperature °C
RθJA = Thermal resistance
PD = Total power dissipation based on number of switches being used.
Compare the calculated junction temperature with the initial estimate. If they do not agree within a few degrees, repeat the calculation, using the calculated value as the new estimate. Two or three iterations are generally sufficient to get a reasonable answer.