TLE42644_14 Datasheet, PDF (12/15 Pages) Infineon Technologies AG – Very Low Dropout Voltage

TLE42644
Application Information
R_thJA,max = (T_j,max – T_a) / P_D
= (150 °C – 105 °C) / 0.479 W
= 93.9 K/W
As a result, the PCB design must ensure a thermal resistance R_thJA lower than 93.9 K/W. By considering
TLE42644G (PG-SOT223-4 package) and according to “Thermal Resistance” on Page 6, at least 300 mm²
heatsink area is needed on the FR4 1s0p PCB, or the FR4 2s2p board can be used.
6.4
Reverse Polarity Protection
TLE42644 is self protected against reverse polarity faults and allows negative supply voltage. External reverse
polarity diode is not needed. However, the absolute maximum ratings of the device as specified in “Absolute
Maximum Ratings” on Page 5 must be kept.
The reverse voltage causes several small currents to flow into the IC hence increasing its junction temperature.
As the thermal shut down circuitry does not work in the reverse polarity condition, designers have to consider this
in their thermal design.
Data Sheet
12
Rev. 1.1, 2014-07-03