1、 Overview

In the design of high-frequency switching power supplies, the loss of output rectifier Schottky diodes directly affects system efficiency, temperature rise, and cost. This article compares the performance differences between Huaxuanyang Electronics SS54 (SMC packaging) and industry typical products (brand A) based on five core parameters: conduction loss (VF), reverse recovery characteristics (TRR), high temperature leakage (IR), thermal management (R θ JA), and temperature resistance (Tj (max)). Through quantitative calculations, the selection strategy is clarified to help engineers achieve a precise balance between efficiency, temperature rise, and cost.

2、 Main text

1. Definition of key parameters and engineering impact

VF (forward voltage drop): The anode cathode voltage difference when a diode is conducting determines the conduction loss (P_cond=VF × IF × D, where D is the duty cycle).   

IR (reverse leakage current): Leakage current during reverse bias, causing static losses at high temperatures (P_leak=VR × IR).   

Trr (reverse recovery time): The rate of charge dissipation during the shutdown process affects the switching loss (P_sw ∝ trr × f_sw, where f_sw is the switching frequency).   

R θ JA (thermal resistance): The thermal conductivity efficiency index of the temperature difference between the junction temperature and the environment (Δ T=P_diss × R θ JA).   

Tj (max) (maximum junction temperature): The upper limit of the device‘s safe operating temperature.

2. Comparison of Huaxuanyang SS54 vs. Brand A Parameters

3. Quantitative calculation of losses and temperature rise (taking 5A/100kHz application as an example)

Scene setting:

Input voltage 24V, output voltage 12V (D=50%)

Environmental temperature Ta=85 ° C

Huaxuanyang SS54 loss calculation:

1. Conduction loss: P_cond=VF × IF × D=0.55V × 5A × 0.5=1.375W

2. Static loss: P_leak=VR × IR=12V × 50 μ A=0.0006W (negligible)

3. Switch loss (empirical formula):

P_sw = 0.5 × VR × IF × trr × f_sw  

= 0.5 × 12V × 5A × 35ns × 100kHz = 0.105W  

4. Total power consumption: P_total ≈ 1.375W+0.105W=1.48W

5. * * Estimation of junction temperature * *:

Tj = Ta + P_total × RθJA = 85°C + 1.48W × 60°C/W = 85°C + 88.8°C = 173.8°C  

*(Above the Tj (max)=150 ° C limit of 23.8 ° C, forced heat dissipation is required to ensure safety)*

Comparison results of brand A:

P_cond = 0.65V × 5A × 0.5 = 1.625W（↑18%）  

P_sw = 0.5 × 12V × 5A × 50ns × 100kHz = 0.15W（↑43%）  

Tj=85 ° C+(1.625W+0.15W) × 80 ° C/W=85 ° C+142 ° C=227 ° C → Overtemperature failure!

>Calculation basis:

>The conduction/static loss formula is derived from IEEE standard JESD77B

>Switch loss model reference "Power Electronics: Converter, Applications"

>Thermal model based on JEDEC JESD51 series standards

4. Engineering selection strategy

High switching frequency scenario (>200kHz):

Priority should be given to SS54 with trr ≤ 35ns to avoid switch losses dominating efficiency (brand A has a loss increase of over 40% due to trr=50ns).   

High temperature environment application (Ta>85 ° C):

The IR of SS54 is ≤ 50 μ A @ 125 ° C and Tj (max)=150 ° C, significantly reducing the risk of thermal runaway (brand A has an IR of 120 μ A at 125 ° C).   

Compact Space Design:

SS54 with R θ JA ≤ 60 ° C/W can reduce the size of heat sinks and save 30% layout area compared to brand A (80 ° C/W).

3、 Conclusion

Huaxuanyang Electronics SS54 achieves:

1. Efficiency improvement: The comprehensive loss is reduced by 20% and 30% compared to competitors, especially suitable for applications above 200kHz;   

2. Temperature rise control: Safe operation at a junction temperature of 150 ° C, supporting long-term operation in high-temperature environments;   

3. Cost optimization: Reduce heat dissipation requirements and lower system BOM costs.   

Recommended scenarios: USB PD fast charging, server power supply, vehicle DCDC module and other high-frequency, high-density power supply designs. Choosing SS54 can significantly improve the MTBF (mean time between failures) of the system.