Athena Power AP-MFATX40P8 400 W Power Supply Review

Secondary Analysis

The Athena Power AP-MFATX40P8 uses a regular design in its secondary, with Schottky rectifiers.

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. As an exercise, we can assume a duty cycle of 30 percent.

The +12 V output uses two SBR40U60CT Schottky rectifiers (40 A, 20 A per internal diode at 100° C, 0.60 V maximum voltage drop). This gives us a maximum theoretical current of 57 A or 686 W for the +12 V output. The 350 W model uses similar rectifiers here.

The +5 V output uses one STPS30L45CT Schottky rectifier (30 A, 15 A per internal diode at 135° C, 0.74 V maximum voltage drop). This gives us a maximum theoretical current of 21 A or 107 W for the +5 V output. The 350 W model uses a similar rectifier here.  

The +3.3 V output uses another STPS30L45CT Schottky rectifier. This gives us a maximum theoretical current of 21 A or 71 W for the +3.3 V output. This component is identical to the one used on the 350 W model.

Figure 14: The +5 V and +12 V rectifiers

Figure 15: The +3.3 V rectifier

This power supply uses a PS223 monitoring integrated circuit, which supports over voltage (OVP), under voltage (UVP), over current (OCP), and over temperature (OTP) protections. This chip offers two +12 V channels, correctly matching the number of +12 V rails advertised by the manufacturer.

Figure 16: Monitoring circuit

Some of the electrolytic capacitors that filter the outputs are Japanese, from Sanyo, while others are from Asia’x. They are all labeled at 105° C, as usual.

In summary, both 350 W and 400 W models use similar components; however, the 400 W model uses a revised printed circuit board (revision A1), while the 350 W model uses revision A0.