ZHCSL05C October 2019 – October 2023 TPS65313-Q1
PRODUCTION DATA
Table 12-2 lists all the typical values required to estimate the junction temperature of the device. The efficiency values are from the measurements done on the evaluation module (EVM) for the TPS65313-Q1 device (TPS65313-EVM).
REGULATOR | INPUT VOLTAGE | OUTPUT VOLTAGE | LOAD CURRENT(1) | EFFICIENCY AT SPECIFIED LOAD CURRENT(2) | INDUCTOR DCR |
---|---|---|---|---|---|
BUCK1 | 12 V | 3.3 V | 1 A | 83% | 0.018 Ω |
BUCK2 | 3.3 V | 1.8 V | 1 A | 88% | 0.035 Ω |
BOOST | 3.3 V | 5 V | 0.3 A | 93% | 0.052 Ω |
Based on the power dissipation equations, the results are as follows:
For this TI thermal simulation example, the ambient temperature is assumed to be the PCB temperature measured on the PCB, 1-mm away from the device. Also no additional heat sink was used and the device is assumed to be fully soldered to the thermal pad with thermal vias on the PCB. For this condition, the junction-to-board characterization parameter (ψJB) is the appropriate thermal resistance parameter to be used to estimate the device junction temperature. Unlike JEDEC standard simulation, this simulation does not assume uniform power distribution across the device when estimating the thermal resistance. But, hot spot-based simulation was done to estimate the thermal resistance.
Table 12-3 lists the specifications and thermal results for the standard and custom PCBs.
SPECIFICATION | STANDARD BOARD | CUSTOM BOARD |
---|---|---|
Board size (l × w) | 75 mm × 100 mm | 30 mm × 30 mm |
Board thickness | 1.6 mm | 1.6 mm |
Number of layers | 4 | 6 |
Size of thermal via array | 4 × 4 with vias connected to one inner layer | 4 × 4 with vias connected to each inner layer |
Thermal pad | Fully soldered | Fully soldered |
Thickness of each top and bottom copper layer | 2 oz | 2 oz |
Thickness of inner layers | 1 oz | 1 oz |
Simulated junction-to-board characterization parameter (ψJB) | 14°C/W | 11°C/W |
Based on WD Q&A Sequence Run for WD Q&A Multi-Answer Mode , the calculated junction temperature at a PCB temperature of 125°C and 1.59-W internal power dissipation of the device | 147°C | 142°C |
These calculations are only for the purpose of initial estimation and users must validate the thermal performance on their board to make sure that the junction temperature of the device is kept lower than 150°C. If the junction temperature of the device is greater than 150°C, special thermal management is required.