A Look Inside And Component Analysis
Before proceeding with this page, we strongly encourage you to a look at our PSUs 101 article, which provides valuable information about PSUs and their operation, allowing you to better understand the components we're about to discuss. Our main tools for disassembling PSUs are a Thermaltronics soldering and rework station and a Hakko FR-300 desoldering gun.
|Transient Filter||4x Y caps, 3x X caps, 2x CM chokes, 1x DM choke, 1x MOV|
|Inrush Protection||NTC Thermistor & Relay|
|Bridge Rectifier(s)||2x GBJ1506 (600V, 15A @ 100 °C)|
|APFC MOSFETs||2x Infineon IPP60R199CP (650V, 10A @ 100 °C, 0.199Ω)|
|APFC Boost Diode||1x SCS110AG (600V, 10A @ 117 °C)|
|Hold-up Cap(s)||2x Rubycon (420V, 330uF each or 660uF combined, 2000h @ 105 °C, MXH)|
|Main Switchers||4x Infineon IPP50R399CP (560V, 6A @ 100 °C, 0.399Ω)|
|APFC Controller||On Semiconductor NPC1654|
|Switching Controller||Champion CM6901|
|Topology||Primary side: Full-Bridge & LLC Resonant Converter Secondary side: Synchronous Rectification & DC-DC converters|
|+12V MOSFETs||unknown number of FETs|
|5V & 3.3V||DC-DC Converters: 6x Infineon BSC0906NS (30V, 40A @ 100 °C, 4.5mΩ) PWM Controller: APW7159|
|Filtering Capacitors||Electrolytics: Nippon Chemi-Con (105 °C, KY, KZE) Polymers: Nippon Chemi-Con, FPCAP|
|Supervisor IC||Weltrend WT7257V & AS393|
|Fan Model||Hong Hua HA13525H12F-Z (12V, 0.5A, 2300 RPM, Fluid Dynamic Bearing)|
|Standby PWM Controller||ICE2QR4765|
The XTR 850W utilizes Seasonic's KM3S platform (thanks to user Orion for pointing this out), which is a newer version of the KM3 design. The differences between the KM3 and KM3S platforms are limited and there is one thing that we know for sure: although the KM3 platform is several years old, it still delivers high performance, easily matching the 80 PLUS Gold-rated competition so we expect high performance from the KM3S design. A full-bridge topology is used on the primary side, along with an LLC resonant converter. On the secondary side, DC-DC converters are installed on the modular panel to decrease energy losses on cables. The less distance power has to travel, the lower the circuit's overall resistance. Less energy is consequently wasted as heat.
XFX's component quality is high. Besides Infineon FETs, Seasonic also uses Japanese caps with high temperature ratings. We would like to see better assembly quality, though. Most specific, we didn't like the view of the leaning heat sinks. This might not affect performance in any significant way, but they don't look good.
The first part of the transient filter is properly shielded by a metallic cover grounded to the chassis. This part includes a CM choke, a X cap along with a pair of Y ones. The EMI filter continues on the main PCB with two more X caps, a CM choke and a DM one, and an MOV.
An NTC thermistor along with a bypass relay protect against large inrush currents during the PSU's start-up phase.
A couple of parallel bridge rectifiers (2x GBJ1506) fully rectify the incoming AC signal. By using two rectifiers in parallel, amperage is split between them, lowering energy losses.
The APFC converter uses two Infineon IPP60R199CP FETs along with a single SCS110AG boost diode. The bulk caps are a pair of Rubycons (420V, 2000h @ 105 °C, MXH) that have 660uF combined capacity. Although this seems low, thanks to a proper design, you get a longer hold-up time than the ATX spec requires.
The APFC controller, an NPC1654 IC, is installed on a small vertical PCB.
The main switching FETs are four Infineon IPP50R399CPs configured in a full-bridge topology. They're installed on a dedicated heat sink. An LLC resonant converter helps lower switching losses, providing a significant efficiency boost.
The LLC resonant controller is a Champion CM6901 IC and it is installed on the same PCB that houses the +12V FETs.
A large heat sink divided into two parts cools the FETs that generate the +12V rail. Under the lower part of this sink, we notice several FPCAP polymer caps. Unfortunately, there is no way to identify the +12V FETs without completely dismantling (and destroying) the unit.
Most filtering caps on the secondary side are by Chemi-Con and are rated at 105 °C. We also spotted a small Rubycon electrolytic cap.
The DC-DC converters are installed on the modular PCB. Their common PWM controller is an APW7159 IC. Each converter uses three Infineon BSC0906NS FETs.
On the front side of the modular board, many Chemi-Con polymer caps filter the rails. The lower modular sockets are directly soldered to the mainboard for decreased voltage drops.
The vertical board in the photos above houses a Weltrend WT7257V supervisor IC and an AS393 dual-voltage comparator. This supervisor IC supports OCP for up to two +12V virtual rails, though XFX's specs only mention one.
The standby PWM controller is an ICE2QR4765 IC.
The soldering quality is pretty good, although it's not the best we have seen from Seasonic. At least all component leads are trimmed well.
The cooling fan is by Hong Hua and its model number is HA13525H12F-Z (135mm, 12V, 0.5A, 2300 RPM max). It's a strong fan that can get really loud at higher speeds. With semi-passive mode enabled it'll obviously be silent under light loads, but as the load increases the fan starts making its presence felt.