en ru ua


logo minifile

::>Power supplies > 2015 > 02 > Seasonic Platinum 520 Fanless (SS-520FL2)

Print version
Republish review



Power supply Seasonic Platinum 520 Fanless: review and testing

After testing the new revision of a series of power supply units Seasonic Platinum, we, of course, could not ignore solutions with fully passive cooling system. Primarily such models attract attention due to its unique ability to work without making a single sound. A few years ago one of the limiting factors in the growth of their popularity was relatively small rated power. Today, this barrier is eliminated by both the power-supply designers and manufacturers of other components. First increase the value of the power output to 500-600 W, and the second produced energy-efficient processors and graphics cards.

Seasonic Platinum 520 Fanless (SS-520FL2)

In other words, modern fanless models such as the Seasonic Platinum 520 Fanless (SS-520FL2), easily cope with most average configurations, including a gaming systems built on the basis of high-end components.

The specs:


Seasonic Platinum 520 Fanless

(Seasonic SS-520FL2)



Rated capacity, W


12V channel capacity, W


+3,3V and +5V channel capacity, W


Q-ty of +12V lines


Outputs, А









+5VSB (stand-by power line)



4 (6+2-pin)

Support of technologies NVIDIA SLI / AMD CrossFireX




Efficiency, %

> 91

Certified 80 PLUS


Power factor, %


Method of Power Factor balancing


Input voltage, V

100 - 240

Frequency, Hz

50 - 60

Input current, А

4 - 7

Fan dimensions, mm


Fan speed controller

No (passive cooling system)

Noise level, dB


Support for energy saving states C6 / C7(Intel Haswell Ready)


Correspondence to environmental standards, electromagnetic safety and compatibility (EMI/EMC)

CB, CCC, cUL, TUV, cTUVus, GOST-R, BSMI, CE, FCC, C-tick, RoHS, WEEE, ErP Lot 6 2013



Dimension, mm

160 х 150 х 86


Power cord, fastening screws, modular cables, cable holders, straps with adhesive tape, manual, logo sticker 

Warranty, years


Producer website


Product page

Seasonic Platinum 520 Fanless

Packaging and content

Seasonic Platinum 520 Fanless (SS-520FL2)

Power supply Seasonic Platinum 520 Fanless is shipped in a cardboard box which provides protection against shocks and possible mechanical damages. Its front side contains the main features of devices, such as rated power (520 W), compliance with energy efficiency standard 80 PLUS Platinum and support of energy-saving states C6/C7, characteristic of processors Intel Haswell. Of course, the manufacturer also emphasized that this model belongs to a series Fanless power supplies.

Seasonic Platinum 520 Fanless (SS-520FL2)

Other technical data can be detected on the reverse side of the box. This section decribes the design features and technologies that are used in the Seasonic Platinum 520 Fanless and allow to achieve such a high level of energy efficiency. Separately we want to note the presence of a 7-year warranty and excellent stability of output voltages (according to the manufacturer, the deviations from the nominal value shall not exceed ± 2%).

Seasonic Platinum 520 Fanless (SS-520FL2)

Supply set is rich enough, and includes all the necessary components, namely:

  • AC power cord;
  • screws to secure;
  • modular cables, which are in a special two-piece handbag;
  • five holders and three ties to secure the wires;
  • sticker with the logo of the company;
  • manual.

A set of modular cables is not demonstrated in the photo, but it will be discussed little bit latter. Also in the box we found a leaflet with a reminder that the power supply belongs to the fanless type, so it is strongly dependent on the cooling air distribution inside the computer case.

Seasonic Platinum 520 Fanless (SS-520FL2)

Those who deal with this kind of devices for the first time, it is strongly recommended to follow the instructions arranged on the tape:

  • in the case of bottom location of the power supply the new product should be placed grille upwards; 
  • in the case with top location of the power supply test model should be placed the grille down, ensure beforehand that the space around the computer case is well ventilated (the option placing of it in a special niche of the table is not suitable);
  • around all panels with vents the body of the power supply can have enough space.

Also, before installing Fanless Seasonic Platinum 520 in computer case don’t forget to remove that this tape.


Seasonic Platinum 520 Fanless (SS-520FL2)

Externally this model is a bit different from the usual power supply units of the same capacity. Firstly do note the absence of the fan and the presence of perforation absolutely in all panels. This solution contributes a better heat dissipation via natural convection. Moreover, there is a possibility to use any external air flow for blowing the components.

Seasonic Platinum 520 Fanless (SS-520FL2)

The biggest mesh is on the top cover, so it is very important to keep it against overlapping during the operation of the power supply. Despite the abundance of vents, the case has not lost its rigidity. The build and handling quality of the panels is also high. The dimensions are 160 x 150 x 86 mm. That is in this respect Fanless Seasonic Platinum 520 is no different from the usual solutions of similar capacity, equipped with modular connectors.

Seasonic Platinum 520 Fanless (SS-520FL2)

However, here more correct is to speak about a "modular connector", but "fully modular connectors." Since Fanless Seasonic Platinum 520 belongs to the top-end series Seasonic Platinum, most of its advantages are reflected in the model. They include fully modular cabling system, where even the main cables leading to the motherboard are detachable. This approach makes the process of connecting components and routing of cables as simple as possible, especially if we are talking about some kind of multi-functional building. All connectors are signed and have a different design. Below is a purpose for each of them:

  • 18-pin and 10-pin («M/B») - to power the motherboard; 
  • four 6-pin («Peripheral IDE/SATA») - to power the periphery; 
  • four 8-pin («CPU/PCI-E») - for additional power processor and graphics card. 

Seasonic Platinum 520 Fanless (SS-520FL2)

Almost all of the cables are in the form of strips that positively affects their usability. Main power connectors are detachable and have the following configuration: 20+4-pin ATX and 4+4-pin ATX12V. Power is supplied to the video cards via four 6+2-pin PCIe, while the other 500 W solutions can not always boast the presence of even two such connectors. Thus, on the basis of 520 Fanless Seasonic Platinum you can easily build a gaming configuration with a bunch of graphics cards that operate in modes NVIDIA SLI or AMD CrossFireX. The only thing you need to mention is that prior to building of the computer you need to pay special attention to ventilation by the body, in which lower graphics adapter does not prevent removal of heat from the power supply. Given the large number of offerings on the market, will not be difficult to pick up the necessary components.

The number and configuration of cables for connecting peripherals is proper. Available connectors are enough to connect multiple drives, as well as to power the other components that require the connector PATA.

Socket type


Cable length to socket (connectors), cm

Modular (detachable) cables

20+4-pin power socket ATX



4+4-pin power socket ATX12V



two 6+2-pin power sockets PCIe



three sockets PATA



two sockets PATA



four sockets SATA



two sockets SATA



adapter PATA-FDD



Seasonic Platinum 520 Fanless (SS-520FL2)

Now let's take a closer look at the technical characteristics of the power supply Seasonic SS-520FL2. Its nominal power is 520 W. Channel +12V is formed as a single line with a loading capacity of up to 43 A. In other words, if necessary, it is possible to "remove" 99.2% of the total capacity, which is quite relevant for modern components. In addition, the field to experiment with their overclocking is significantly expanded. Lines +3.3V and +5V have a maximum total power of 100 W and are designed for a load of 20 A each.

As you might guess from the title, in terms of Energy Efficiency Fanless Seasonic Platinum 520 complies with 80 PLUS Platinum. This is also indicated by the picture on the label. Power supplies are standardized according to 80 PLUS Platinum if their efficiency for 230V at loads of 20%, 50% and 100% does not fall below 90%, 94% and 91%, respectively.

Also note a wide input voltage range (100 - 240), which eliminates the external voltage regulators in an unstable power supply.

Internal device

Seasonic Platinum 520 Fanless (SS-520FL2)

The process of dismantling the power supply Seasonic Platinum 520 Fanless is quite standard (except that there is no usual fan): you need to unscrew the screws securing the top cover. We draw your attention to the presence of a special sticker with the inscription «Warranty void if removed».

Seasonic Platinum 520 Fanless (SS-520FL2)

The heart of the new revision of the model 520 Fanless Seasonic Platinum is familiar to us platform Seasonic KM3 from other high quality power supply from the Sea Sonic Electronics. It has repeatedly been subjected to severe tests in our test lab and has always demonstrated a very strong performance. However, one aim is to get active cooling, and another is to get the same without the use of a fan.

Seasonic Platinum 520 Fanless (SS-520FL2)

The company's engineers were known about the difficulties they would face. Therefore they took care of on the effectiveness of the passive cooling system, providing all the power group elements by massive radiators. And in most cases it terms of size they even surpass those that we could see a more powerful Seasonic Platinum 760 or Seasonic Platinum 860.

Seasonic Platinum 520 Fanless (SS-520FL2)

Moreover, the manufacturer also did not save on the elements to increase the amount of free space in the supply unit. Instead, he used the most energy-efficient diodes and transistors and capacitors designed for high temperatures.

Seasonic Platinum 520 Fanless (SS-520FL2)

Seasonic Platinum 520 Fanless (SS-520FL2)

As for the implementation of the nodes, it is at the high level, because we are dealing with a good solution of the top series. Behind the power outlet is located a part of EMI-filter (choke, X- and two Y-capacitors), hidden from us by a kind of screen. The remaining components (varistor, two chokes two X- and Y-two capacitors) are arranged directly at the main PCB. Recall that the purpose of this node is to smooth high frequency noise emitted in the power supply network. Also it bears the function of lightning protection. We liked the manufacturer's approach to isolation of individual elements not only as part of the filter, but in the other structural modules of test model.

Seasonic Platinum 520 Fanless (SS-520FL2)

Due to the tight layout the characteristics of the bridge for rectifying the input voltage could were not determined. We can only say that it includes two diode assemblies. The power part of the active power factor correction (APFC) is represented by a Schottky diode STPSC606D and two FETs Infineon 6R160C6, built on technology CoolMOS and has a relatively low resistance of the open channel (160 mOhm).

Seasonic Platinum 520 Fanless (SS-520FL2)

High-voltage circuit capacitor (330 uF x 420 V) is manufactured by Japanese company Hitachi and belongs to a series of high-temperature (105°C). Its quality has no complaints.

Seasonic Platinum 520 Fanless (SS-520FL2)

Like other high-performance solutions the model Fanless Seasonic Platinum 520 applies resonant converter with a full bridge. Its keys are the four transistors Infineon 5R250P, which work in pairs under the control of the PWM controller CM6901.

Seasonic Platinum 520 Fanless (SS-520FL2)

The voltage of main line +12V that provides voltage +3.3V and +5V is formed a synchronous rectifier. Structurally, the organization of low-voltage part in Fanless Seasonic Platinum 520 is very similar to more powerful "platinum" devices Seasonic Platinum 760 and Seasonic Platinum 860. The biggest modernization deals with cooling system: the usual radiators were increased in size and have additional coolers. Also the number and size of power transistors on the channel +12V were modified. However, it is not possible to test this assumption without dismantling some nodes.

Seasonic Platinum 520 Fanless (SS-520FL2)

When designing fanless solutions engineers Sea Sonic Electronics used a useful proprietary technology - the use of case of the power supply for heat dissipation. You can learn this process on the photo above.

Seasonic Platinum 520 Fanless (SS-520FL2)

Converters of remaining voltages are wired on a separate board. Despite the fact that here are much smaller currents, the manufacturer decided not to risk and equipped force elements DC-DC-converters by additional aluminum plate.

Seasonic Platinum 520 Fanless (SS-520FL2)

After dismantling it you can see that the formation of lines +3.3V and +5V is provided by six transistors Renesas RJK0332DPB (three for each channel) with open resistance only 3.6 milliohms. Control of DC-DC-converters is provided by the PWM controller APW7159.

Seasonic Platinum 520 Fanless (SS-520FL2)

On the reverse side of the card is part of the modular connectors and other converter components: two coils and filter capacitors of polymer type (470 uF x 16 V and 560 uF x 6.3 V). This configuration of a low voltage part has several advantages. Firstly, there is a free space on the main PCB. Secondly, the energy losses and noise on the power supply outputs are minimized. And thirdly, installation of elements, which entails increasing overall product quality is simplified.

Outputs with a large load (for connecting additional power processor and graphics card), are located directly on the main PCB to, once again, to reduce the energy loss due to underwater lines.

Seasonic Platinum 520 Fanless (SS-520FL2)

In addition to solid capacitors (330 uF x 16 V), the channel +12V has several items with liquid electrolyte (2200 uF x 16 V). Their producer is well-known Japanese company Nippon Chemi-Con, and they belong to the high-temperature series (up to 105°C). All this indicates about the high quality and long service life.

Seasonic Platinum 520 Fanless (SS-520FL2)

According to the technical specifications, model Fanless Seasonic Platinum 520 has a whole row of protection (OVP/UVP/OPP/SCP/OCP/OTP), including protection against overload and overheating. Last option in the fanless power supply is very important. The node is based on chip-supervisor Weltrend WT7527V.

Социальные комментарии Cackle
Site Search
facebook vk YouTube
google+ twitter rss