As a first step to evaluate the thermal performances on all three EVM boards, the case temperature of the IC is measured using a thermal camera for Vin = 5 V, Vout = 3.3 V over a load range of 250 mA to 2 A. Table 4-3 show an example of thermal pictures captured for Iout = 2A.

Table 4-3 Thermal Picture on TLV62569 EVMs at Vin = 5 V, Vout = 3.3 V, and Iout = 2 A

SOT23-5 PACKAGE	SOT23-6 PACKAGE	SOT563 PACKAGE (DRL)
Case temperature: Tcase = 65°C	Case temperature: Tcase = 53°C	Case temperature Tcase = 72°C

The results of IC case temperature measurements over the entire load range up to 2 A are compiled in Figure 4-4. As a next step, the junction temperatures of the IC in the three different packages are deducted using Equation 1. Figure 4-5 shows the results.

The thermal measurements are represented versus output current and IC power dissipation to demonstrate the linear relation between IC temperature and IC power dissipation on each of the EVMs.

Figure 4-4 Case Temperature vs. Dissipated Power

Figure 4-5 Case Temperature vs. Output Current

Figure 4-6 Calculated Junction Temperature vs. Dissipated Power

Figure 4-7 Calculated Junction Temperature vs. Output current

Thermal performances are critical for higher load current as power dissipation becomes a challenge with conduction losses increasing.

From graphs on Figure 4-2, Figure 4-4, and Table 4-4, three main observations can be made:

• SOT23-5 has the highest junction temperature.
• SOT23-6 has the lowest Junction and case temperature.
• SOT563 has the lowest junction to top temperature raise.

Figure 4-8 shows thermal comparison of TPS563201 and TPS563202. Because of different theta JA, TPS563201 thermal performance is a little better than TPS563202.

This section concentrated on the method to measure and estimate IC temperature and tangible results were shown for the TLV62569. Moving forward, the focus is set on the analysis of these measurement results and the meaning in terms of IC packaging.