A Look Inside and 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. For the identification of tiny parts, we use a Andonstar HDMI Digital Microscope.


This platform reminds us of the Seasonic Focus; however, there are several key differences. According to Mistel, it was designed by its engineers and manufactured by Shang Hung, a factory in Taiwan. We had never heard of this factory before, but judging by this PSU, it does a very good job.


The platform is modern and highly capable. In the primary side is a full bridge topology along with an LLC resonant converter. In the secondary side, a pair of VRMs handle the minor rails, and the +12V rail is regulated by several FETs on the solder side of the main PCB. All caps are of good quality, and Mistel's claim of using nothing but Japanese caps is true. Given the complete lack of forced airflow in a passive unit, lower quality caps would have been bad. Finally, Mistel uses tall heatsinks to increase heat dissipation. It is nice to also a see a heatsink on the main transformer since it can get quite hot, especially under high loads.


The first part of the transient filter is on the AC receptacle and includes a C cap and two Y caps, and it continuous on the main PCB with the same number of caps, two CM chokes, and an MOV.


The two bridge rectifiers can handle up to 50 A current, which is a lot.


The APFC converter uses two Infineon IPA60R099P6 FETs and a G3S06510A boost diode. This is the first time we have come across this diode model. We would prefer a diode from a more well-known brand instead, like CREE. The bulk cap is of high quality, though, and rated at 450 V, contrary to the majority of bulk caps rated at 400–420 V, which is very close to the APFC's DC bus voltage (385VDC). Finally, next to the APFC FETs and diode is the bypass relay of the NTC thermistor responsible for inrush current protection; it is installed on the other side of the heatsink.


Like all heatsinks in this unit, the APFC's heatsink is quite tall. Even the main transformer has a heatsink, which sounds reasonable given there is no active cooling.


The main switching FETs are Four Wuxi NCE Power Semiconductor NCE65T180Fs. While quite strong for the task, we would like to see Infineon FETs used instead. An LLC resonant converter is also utilized, for increased efficiency.


Both the APFC and LLC resonant converters, CM6500 and CM6901 respectively, are provided by Champion and are installed on the solder side of the main PCB.


The FETs that regulate the +12V rails are on the solder side of the main PCB. In total, four Excelliance MOS EMP16N04HS FETs are used.


We could only identify the PWM controller of the DC-DC controller, which is a UP3861. To check on the FETs, we would have had to completely remove the daughter board, which we just didn't have the time for.


The filtering caps are exclusively provided by Japanese companies. The electrolytic ones are from Chemi-Con, which also provides some of the unit's polymer caps. The polymer caps are by FPCAP. Needless to say, a passively cooled PSU with inferior quality caps wouldn't last long, so good parts had to be used.


The supervisor IC is a Weltrend WT7527V. It doesn't support OTP (Over Temperature Protection), so another circuit is most likely used to provide OTP.


The 5VSB circuit uses a 1045 DGAL SBR diode, and its PWM controller is an Excelliance EM8569.


Several polymer caps for ripple-filtering purposes are installed on the primary side of the modular board. We also find a fan header here, which will most likely be utilized by other models based on the same platform.


The RGB LEDs are installed on the backside of the modular board.


Soldering quality is great, which was a nice surprise given Mistel is a newcomer to the PSU market.