Seasonic SS-300TFX Power Supply Review

Secondary Analysis

This power supply comes with four Schottky rectifiers attached to its secondary heatsink.

The maximum theoretical current each line can deliver is given by the formula I / (1 – D), where D is the duty cycle used and I is the maximum current supported by the rectifying diode. Just as an exercise, we can assume a typical duty cycle of 30%.

The +12 V output is produced by two SBR30A45CT Schottky rectifiers, each one capable of delivering up to 30 A (15 A per internal diode at 110° C, 0.50 V maximum voltage drop). This gives us a maximum theoretical current of 43 A or 514 W for the +12 V output.

The +5 V output is produced by one STPS30L30CT Schottky rectifier, which is capable of delivering up to 30 A (15 A per internal diode at 140° C, 0.57 V maximum voltage drop). This gives us a maximum theoretical current of 21 A or 107 W for the +5 V output.

The +3.3 V output is produced by another STPS30L30CT Schottky rectifier, giving us a maximum theoretical current of 21 A or 71 W for the +3.3 V output.

Figure 13: +12 V, +5 V and +3.3 V Rectifiers.

This power supply uses an HY-510N monitoring integrated circuit, which is located on the same printed circuit board as the PFC/PWM controller (see Figure 12). This circuit supports only over voltage (OVP) and under voltage (UVP) protections.

Electrolytic capacitors from the secondary are from Su’scon and OST and labeled at 105° C.