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!




Even the PCB is white, which is a nice touch on Seasonic's part as it even managed to impress us although such details usually pass us by unnoticed. Everything else except for the white-colored PCB and some different components in the APFC converter is exactly the same as in the SS-1050XP3. But such is a good thing since the latter is based on Seasonic's high-end XP3 platform that only uses quality parts. In the primary side are a full-bridge topology and an LLC resonant converter, while the secondary side uses a synchronous design with two VRMs (Voltage Regulation Modules) for the minor rails. The latter are on the modular PCB to reduce energy losses.


A sealed PCB behind the AC receptacle holds a CM choke, four Y caps, and a single X cap. The EMI filter's other components are on the main PCB: four X and Y caps, each, a CM and DM choke, and an MOV. There is also an NTC thermistor for protection against large inrush currents. Right next to is is an electromagnetic relay; it allows the thermistor to cool down quickly, which also increases efficiency levels a bit since no energy is lost on the thermistor while the PSU operates.


Both parallel bridge rectifiers are bolted to a dedicated heatsink. By Vishay, their model number is LVB2560.


The APFC converter uses three Infineon IPP60R165CP fets and a single CREE C3D08060A boost diode. The three parallel hold-up caps are by Nippon Chemi-Con (420 V; 330 μF each or 990 μF combined; 105°C; KMR series). The SS-1050XP3 uses three Infineon IPP60R125CP fets here instead, which are more efficient than the above since they have a lower Rds (on) value and use a single STPSC806D boost diode.


A small daughter-board holds the PFC controller, an NPC1654 IC.


The full-bridge topology uses four Infineon IPP50R250CP fets. An LLC resonant converter is also used. It boosts efficiency by providing near lossless switching.


The LLC resonant controller, a Champion CM6901 IC, is hiding behind the bulk cap in the middle.


A pretty large heatsink that is completely devoid of any components resides in the secondary side. The components this heatsink actually cools down are on the solder side of the main PCB right below it.


Four Fairchild FDMS015N04B fets are used in Seasonic's 1050 W Platinum XP3 platform, while the 1200 W version uses eight of exactly the same type, which is a pretty significant difference for a mere 150 W in capacity.


As with most Seasonic high-end platforms, the casing plays a crucial role in cooling down the +12V fets in the secondary side.


All capacitors on the main PCB in the secondary side, polymer and electrolytic, are by Nippon Chemi-Con. The electrolytic caps are rated at 105°C.


Both VRMs that handle the minor rails are on the modular PCB, which decreases energy losses. Each of these holds three Infineon BSC0906NS fets, and an Anpec APW7159 PWM controller handles both regulators.


The front of the modular PCB only holds two FPCAP polymer caps. FPCAP is a very good brand since it actually belongs to Nichicon who bought it from Fujitsu.


The standby PWM controller is an ICE2QR4765 IC.


The supervisor IC, a Weltrend WT7257V, and the AS393 dual-voltage comparator are installed on the board above. The WT7257V supports OCP for up to two +12V virtual rails, but this unit only has one.


Soldering quality on the main PCB is very good, but we expect no less from a Seasonic product.


We also made a point of taking many close-ups of the mainboard's solder side for your pleasure.


The second and most important difference between the Snow Silent edition and the SS-1050XP3 is the fan. While the latter uses a plain double ball-bearing fan, the Snow Silent comes equipped with a fluid dynamic bearing fan of good quality. These bearings (FDB) last much longer than other types and are able to offer a quiet operation for longer. You see, as time passes by, ball-bearings inevitably wear off, which will affect noise output significantly. Seasonic says such not to happen with fluid dynamic bearings, and we have absolutely no reason not to believe them.