A Look Inside & Component Analysis

Before reading this page, we strongly suggest a look at this article, which will help you understand the internal components of a PSU much better. Our main tool for the disassembly of the PSU is a Thermaltronics TMT-9000S soldering and rework station. It is of extreme quality and is equipped with a matching de-soldering gun. With such equipment in hand, breaking apart every PSU is like a walk in the park!




Though the newer and improved Seasonic platinum platform (codenamed XP3) is out, XFX decided to use the older KM3 platform to reduce cost. We have absolutely no problem with their decision because it is also a great platform more than capable of delivering the top performance to meet today's competition eye to eye. The primary side uses a full-bridge topology and an LLC converter for increased efficiency, while in the secondary side, a synchronous design is used to generate +12V, with two DC-DC converters providing for the minor rails. The main difference between this design and the XP3 platform is that the mosfets which regulate the +12V rail are installed on a vertical daughter-board - the newer platform put these on the solder side of the main PCB, the same location as on older Seasonic designs.


Behind the AC receptacle is a sealed PCB that holds a few of the components for the transient filtering stage: four Y caps, a CM choke, and a single X cap. All other transient filtering components, two X and Y caps, each, two CM chokes, a single DM choke, and an MOV, are on the main PCB. We also found a thermistor here. It protects the unit from large inrush currents and comes with an electromagnetic relay that isolates it from the circuit once the APFC caps are fully charged. The transient filtering stage is perfect since it actually utilizes more parts than absolutely necessary.


The two parallel Vishay bridge rectifiers are installed on a dedicated heatsink, and their model number is LVB2560. They can handle up to 50 A combined!


The APFC converter consists of two Infineon IPP60R099CP fets and a SCS110AG boost diode, and the two parallel hold-up caps are provided by Hitachi (420 V; 390 μF each or 780 μF combined; 105°C; HU series).


A small daughter-board houses the PFC controller: an NPC1654 IC.


The full bridge topology utilizes four Infineon IPP60R099CP fets. An LLC resonant converter is also used to boost efficiency through loss-less switching of the main switchers.


The LLC resonant controller, a Champion CM6901, is installed on this board, along with all the fets that regulate the +12V rail. A quite large heatsink, divided into two parts, cools the aforementioned fets down. Under the lower part of the heatsink reside several FPCAP polymer caps. Unfortunately, the +12V fets were completely covered by the heatsink, so we couldn't count or identify them.


The DC-DC converters are installed on the modular PCB, and their common PWM controller is an APW7159 IC. Each of these uses three Infineon BSC0906NS fets.


Many Chemi-Con polymer caps on the front filter the DC outputs.


The lower modular sockets are directly soldered to the mainboard for decreased voltage drops.


This vertical board houses a Weltrend WT7257V supervisor IC, and an AS393 dual-voltage comparator. This supervisor IC supports OCP for up to two +12V virtual rails, but the unit's specs mention only one.


The standby PWM controller is an ICE2QR4765 IC.


Soldering quality is very good since Seasonic manufactured the unit. All component leads were carefully trimmed, and we didn't found any sloppy soldering joints.


The cooling fan is by Hong Hua, and its model number is HA13525H12F-Z (135 mm, 12 V, 0.5 A, 2300 RPM max). It is a pretty strong fan for even a unit of this capacity. Thankfully, there is a semi-passive mode, so those who want an inaudible operation can have it; that is, at light loads and under normal operating temperatures.