Page 3 - Physical Look - Inside
As always, we opened up our Seasonic PRIME Titanium 850W power supply to take a detailed look at what is going on inside. Please note that doing this at home will void your twelve-year warranty, thanks to the warranty seal Seasonic applied over one of the attachment screws. But for the benefit of you, we cracked ours open so you do not need to, haha. There are no user serviceable parts inside.
Disassembling the Seasonic PRIME Titanium 850W is quite straightforward with the removal of four screws. Built by Seasonic themselves -- probably not surprising to anyone in the room -- our photo above shows an overhead view of the its internal components. At first glance, the build quality appears to be excellent, as one would expect from the company. One unique feature of the PRIME Titanium series is that there are no power cables inside. The rear panel daughterboard is connected to the main PCB by a copper plate to reduce electrical losses and improve output quality. There are four heatsinks inside the power supply with all of them finned at the top. They are of various sizes, as you can see in our photo above.
A quick tug on the shell, and we got straight to the internal inspection. The transient filter stage is the first input stage of a computer power supply, so we will take a look at that first. Seasonic has always done a great job in the past to make sure their power supplies met or exceeded the recommended requirements, and the Seasonic PRIME Titanium is no exception. The Seasonic PRIME Titanium 850W has two common mode chokes, one metal oxide varistor, three metalized polyester X-capacitors, and six ceramic Y-capacitors. This is three times the amount of X and Y capacitors than recommended. Considering how many modern-day PSUs have missing MOVs, I am happy to see it here, as this component is used to stabilize spikes from the AC line. A Sanken A6069H current mode control PWM regulator IC for controlling standby power can be spotted as well.
On the primary side, we can see two Japanese brand Nippon Chemi-Con capacitors. Japanese brand capacitors are usually what we expect from something in this price range, so this is nothing surprising. Our 850W version of Seasonic's PRIME Titanium series incorporates one 680µF x 400V capacitor and one 470µF x 400V capacitor in parallel for an equivalent capacitance of 1150µF. Both of them are rated at 105c; whereas more value oriented power supplies usually use 85c rated capacitors.
The active PFC circuit featured on the Seasonic PRIME Titanium 850W uses two Vishay Semiconductor LVB2560 bridge rectifiers attached to opposite sides of the first heatsink. At 115V, the maximum rectified forward current capacity with heatsink is 25A, so you can theoretically pull up to 5750W (25A * 2 diodes * 115V) from the bridge rectifier at 100% efficiency -- of course, this is limited by the fact that it is not 100% efficient, and also neglects the fact that not every component in the system are able to keep up. The active PFC circuit is controlled by an ON Semiconductor NCP1654 integrated circuit. Further down the line, on the outside of the largest heatsink, we can see two Infineon IPP60R099CP power transistors. This MOSFET is certified for up to 19A at 100c. A ROHM Semiconductor SCS110AG boost diode is placed right next it. Four Infineon IPP50R140CP power MOFSET transistors driven by a pair of Silicon Labs Si8230BD chips are used as the main switchers on the PRIME Titanium 850W power supply. Champion's CM6901 is the switching controller. Each Infineon IPP50R140CP MOFSET can deliver up to 15A at 100 degrees Celsius continuously. These transistors present a maximum resistance of 0.14 ohm when turned on; with a typical resistance of 0.13 ohm according to the manufacturer's data sheet. This on characteristic is called Static Drain-Source On-Resistance, or commonly abbreviated as RDS(on). The more efficient the component is, the lower the RDS(on) value, since it wastes less power with lower resistance.
On the secondary side, we can see more Japanese brand capacitors from Nippon Chemi-Con and Rubycon rated at 105c. As with modern high efficiency power supplies, all rectifiers produce the +12V out -- while the +5V and +3.3V outputs are generated from the +12V output using a DC to DC converter within the power supply unit. An ANPEC APW7159 synchronous buck PWM controller can be spotted in this stage. Four Infineon BSC014N04LS MOSFETs are responsible for generating the +12V output. The BSC014N04LS's rated continuous drain current is 40A at 100c, and a pulsed drain current of 100A. Drain source voltage is rated at 40V, and a RDS(on) value of 0.0014 ohm maximum and 0.0011 ohm typical. Six Infineon BSC0906NS MOSFETs are responsible for generating the +5V and +3.3V outputs. The BSC0906NS's rated continuous drain current is 40A at 100c, and a pulsed drain current of 252A. Drain source voltage is rated at 30V, and a RDS(on) value of 0.0045 ohm maximum and 0.0038 ohm typical. Meanwhile, a Weltrend WT7527V IC provides over/under current and over/under voltage protection. The datasheets for all components mentioned in this review can be found on their respective manufacturer's websites.
At the back, we have a large daughterboard covering the entire rear panel for the modular cable sockets. All modular sockets at the bottom are soldered directly to the main PCB after the secondary stage to reduce power transmission loss. The output connector configuration can be seen on the previous page. Overall, the internal build quality of Seasonic's PRIME Titanium 850W power supply is practically second to none -- nothing short of what we would expect from a flagship product from the company. Components are arranged beautifully for optimal cooling with almost no wires running around inside, and solder points on its green PCB are very clean in general. I would say the Seasonic branded, Seasonic built PRIME Titanium 850W is simply excellent with regards to the selection of components used under the hood.
Lastly, we see a 135mm fan that provides cooling to the Seasonic PRIME Titanium 850W's internal components. It is connected to the mainboard using a 2-pin connector. A 135mm fan is only marginally smaller than the 140mm maximum you can fit in an ATX power supply, and it is beneficial in most cases in providing lots of airflow at lower speeds for quiet operation. Hong Hua is the fan OEM, with HA13525M12F-Z as the model number, as shown in our photo above. Further research indicates the HA13525M12F-Z is a fluid dynamic bearing fan specified at 0.36A for a maximum of speed of 1800 rpm. The fan is not supposed to activate until the PSU is loaded to approximately 350W with Hybrid Mode active. As such, it should remain off for the most part -- and even when it is on, Seasonic uses a silent speed profile, so noise is not going to be a problem at all. Fans with fluid dynamic bearings generally have much longer lifespans compared to sleeve bearing fans, and is quite suitable for this application.
Page Index
1. Introduction, Packaging, Specifications
2. Physical Look - Outside
3. Physical Look - Inside
4. Minor Tests and Conclusion
