TPS735_15 Datasheet, PDF (19/33 Pages) Texas Instruments – TPS735 500-mA, Low Quiescent Current, Ultra-Low Noise, High PSRR,Low-Dropout Linear Regulator

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TPS735
SBVS087L – JUNE 2008 – REVISED JANUARY 2015
Estimating Junction Temperature (continued)
According to Figure 24, the new thermal metrics (Ψ_JT and Ψ_JB) have very little dependency on copper area.
Using Ψ_JT or Ψ_JB with Equation 5 is a good way to estimate T_J by simply measuring T_T or T_B on an application
board.
35
30
25
DRV
DRB
Y_JB
20
15
10
5
DRV
DRB
Y_JT
0
0 1 2 3 4 5 6 7 8 9 10
Board Copper Area (in²)
Figure 24. Ψ_JT and Ψ_JB vs Board Size
T_B on PCB
surface
T_T on top
of IC
T_B on PCB
surface
T_T on top
of IC
1mm
1mm
See note (1)
(a) Example DRB (SON) Package Measurement
(b) Example DRV (SON) Package Measurement
(1) Power dissipation may limit operating range. Check Thermal Information table.
Figure 25. Measuring Points for T_T and T_B
11.5 Package Mounting
Solder pad footprint recommendations for the TPS735 family of devices are available from the TI website at
www.ti.com.
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