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!


The platform looks like that of the older G-550 after a quick glance, so Seasonic only changed a few components. Simply read through the following paragraphs to figure out which ones. The primary side uses an LLC resonant converter to increase efficiency, while the secondary side uses two DC-DC converters with a semi-synchronous design for the rectification of the main rails, and as is stated on the box, lots of polymer filtering caps are used.


Behind the AC receptacle is a small PCB. It hosts four Y caps, one X cap, and a CM choke. The transient filter continues on the main PCB with two more CM chokes, two Y caps, a single X cap, and an MOV.


Like in the previous G-550 unit we reviewed, the heatsink holding the bridge rectifier is leaning off to one side. Some Seasonic engineers are apparently huge fans of Pizza's tower. A GBU10V08 is bolted to the heatsink. It can handle up to 10 A current.


In the APFC, two Infineon IPP50R250CP fets and an STTH8S06D boost diode are used. The older G-550 used two Infineon SPP20N60C3 fets and a CREE C3D06060A boost diode instead. The hold-up cap is provided by Nippon Chemi-Con (330µF, 420V, 105°C, KMR series) and is smaller than the 390 µF cap in the previous G-550, although the cap's other specifications are the same. Right in front of it is the thermistor responsible for protection against large inrush currents.


This vertical daughter-board houses an ICE2HS01G resonant controller (large IC on the left) and an ICE3PCS01 PFC controller (small IC on the right).


Two IPP50R250CP fets are used as primary switchers. Another major difference to the first G-550 is that a pair of MagnaChip MDF18N50 fets are used.


A semi-synchronous rectification scheme with two PSMN2R6-40YS fets and two SBR10U45 Schottky diodes rectifying the +12V rail is utilized in the secondary side. All the above are installed on the solder side of the main PCB. A heatsink on the component side helps lower their operational temperature. The minor rails are generated by two DC-DC converters.


Several polymer Enesol and Chemi-Con caps are responsible for ripple suppression (105°C, KZE & KY series).


The standby PWM controller is an Infineon ICE2QR4765 IC. The Schottky diode responsible for the rectification of the 5VSB rail is an SBR10U45, and it is located on the solder side of the main PCB.


The supervisor IC is a SITI PS223 with support for OTP (Over Temperature Protection) out of the box.


On the front of the modular PCB are four Chemi-Con caps that provide some extra ripple filtering to the outputs.


Soldering quality on the main PCB is quite good.


The cooling fan is provided by Jamicon, and its model number is KF1225B1HR-R (120 mm, 12 V, 0.35 A, 2200 RPM max, 75,000 MTBF, 81.17 CFM). This is another change over the old G-550 since it uses an ADDA fan with similar specifications.