SLVAEB1A March 2020 – October 2021 TLV62568 , TLV62569 , TLV62585
The junction temperature of the IC is a crucial parameter for good thermal design. For further details on thermal parameters of ICs, see the Semiconductor and IC Package Thermal Metrics Application Report.
The reliable method to estimate the junction temperature of a DC/DC converter is to use the junction-to-board characterization parameter of the IC, ψJT , specified in Table 3-2 of the TLV62569 2-A High Efficiency Synchronous Buck Converter in SOT Package Data Sheet with Equation 1.
| PARAMETER | DESCRIPTION | COMMENTS |
|---|---|---|
| Tj | IC junction temperature | Target value to calculate |
| Tcase | IC case temperature | Can be easily measured for given operating condition with a thermal camera as shown on figure 1. |
| ψJT | Junction-to-top characterization parameter | Specified in the TLV62569 2-A High Efficiency Synchronous Buck Converter in SOT Package Data Sheet. See table 1. |
| PIC, diss | Dissipated power in the IC for the given operating conditions | This parameter needs to be estimated carefully to have more reliable results (see below). |
There are two options to estimate the IC power dissipation PIC,diss. The first and easiest option to estimate PIC,diss is the WEBENCH? Power Designer Tool for the required operating conditions. The second option is to use Equation 2:
| PARAMETER | DESCRIPTION | COMMENTS |
|---|---|---|
| PIC, diss | IC power dissipation | |
| Pdiss | Total dissipated power Pdiss = (1 - n) × (Pout / η ) |
Pout: Output power |
| η : Efficiency of the power stage – can be found in the TLV62569 2-A High Efficiency Synchronous Buck Converter in SOT Package Data Sheet or modeled in WEBENCH? | ||
| Pind | DC power losses in inductor Pind = DCR × Iout2 |
DCR: inductor series resistor |
| This parameter can be simulated in some manufacturer's website or in WEBENCH? |
It is important to model the dissipated power in the inductor to have a more reliable estimation of the junction temperature. As a general rule, it is good enough to model only the DC losses of the inductor.
| THERMAL METRIC | DEV (5 PINS) | DDC (6 PINS) | DRL (6 PINS) | UNIT |
|---|---|---|---|---|
| RθJA | 188.2 | 106.2 | 146.3 | °C/W |
| RθJC(top) | 137.5 | 52.9 | 51.0 | °C/W |
| RθJB | 41.2 | 31.2 | 27.0 | °C/W |
| ψJT | 31.4 | 11.3 | 2.2 | °C/W |
| ψJB | 40.6 | 31.6 | 27.6 | °C/W |
| RθJC(bot) | N/A | N/A | N/A | °C/W |
| THERMAL METRIC | TPS563201 | TPS563202 | UNIT |
|---|---|---|---|
| RθJA | 92.6 | 137 | °C/W |
| RθJA_Effective | 53.0 | 65.0 | °C/W |
| RθJC(top) | 48.5 | 43.2 | °C/W |
| RθJB | 15.5 | 22.0 | °C/W |
| ψJT | 2.5 | 0.9 | °C/W |
| ψJB | 15.5 | 21.8 | °C/W |
In this section, the different relevance of thermal performance across EE applications were explained and the important parameters for good thermal performance evaluation were introduced. The next section focuses on the specific thermal performance of the TLV62569 across the three different packages: SOT23-5, SOT23-6, and SOT563. And introduces TPS563201 and TPS563202 performance.