Page 3 - Physical Look - Inside
In order to further investigate the design details of the SilverStone Nightjar NJ700 700W power supply unit, some panel removal is required. It is important to note two important concerns before disassembling any power supply unit. First, certain components, such as the capacitors, may cause an electrical shock if not discharged properly. Second, your 5-year warranty will be voided if the screws on the power supply unit are removed. Therefore, unnecessary disassembling of a power supply unit should be avoided.
Once the top panel of the NJ700 is removed, a closer look of the electronic components can be done. The OEM for the power supply is Seasonic, which has a long history of excellent quality products. It is basically the same as the Seasonic PRIME FANLESS TX-700 700W, except SilverStone claims they have spent additional time to eliminate electrical noise. Note this product is a passive cooling PSU, meaning there is no fan inside. This kind of design requires the use of high-quality components and lots of heatsinks. Now we can take a look at the inside so we may have better understanding of how it can deliver 700W of power without an internal cooling fan.
Let us first take a look at the transient filter stage of the SilverStone Nightjar NJ700 700W. The function of the transient filter stage is to protect the computer from power line noise and voltage spikes. In the Nightjar NJ700 700W power supply unit, the transient filter stage contains two X-capacitors and two Y-capacitors near the AC receptacle module. A fuse is zip-tied there as well. Moving down, we can see one more X-capacitor and four Y-capacitors. The transient filter stage also has two white common mode chokes and one metal oxide varistor. The MOV here is to prevent the computer from being damaged by lightning surges. It is worth mentioning not all the power supply units in the market have a MOV like this one does.
Now, we move on to the primary side. The two big capacitors in the photo are from Nippon Chemi-Con, which are both rated at 470µF at 400V. Two capacitors combined yields a total capacitance of 940µF. The temperature is rated at 105c, which is the great in terms of durability. This product uses only Japanese-made capacitors, which costs more than those made in other places like China, but the quality is better.
By the right-hand side of the bulk capacitors in the photo, there is a large heatsink panel. There are two rectifying bridges attached to that heatsink. From what I can see, there are two Vishay LVB2560 rectifying bridges attached to that heatsink. At 115V, the maximum rectified forward current capacity with heatsink is 25A, so you can theoretically pull up to 5750W (2 diodes * 25A * 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 is able to keep up.
On the large heatsink panel, there is also a Cree C3D06060A Schottky diode. Behind the large heatsink panel in the photo, there are two smaller heatsinks. On the right-hand side, you can find a pair of Infineon IPP60R099C7 as the APFC MOSFETs. The Infineon IPP60R099C7 can support 14A at 100c, typical RDS(on) of 85 mΩ, and maximum RDS(on) of 99 mΩ. On the left-hand side, the smaller heatsink panel attaches four Infineon IPP50R140CP as the main switchers. The IPP50R140CP can deliver power up to 15A continuously and a maximum and typical drain-source on-resistance of 140 mΩ and 130 mΩ, respectively, according to the datasheet. Note the lower the drain-source on-resistance, the more efficient the transistor will be. As for the APFC controller, NJ700 has an ON Semiconductor NCP1654.
The electrolytic capacitors on the secondary side are also from Nippon Chemi-Con, which means they are manufactured in Japan and are rated at 105c. The polymer capacitors are from a Japanese company as well; they are either made by Nichicon or Rubycon. For a modern power supply unit, the power output from the rectifiers is +12V. Eight Infineon BSC014N04LS are responsible for generating +12V, and they can provide current up to 125A continuously at 100c. The +12V output of the power supply unit can just directly use the power from the rectifiers. However, the +5V and +3.3V outputs are converted from the +12V output. The conversion functionality is mainly realized by the components such as the DC-to-DC converter. The NJ700 utilizes six Infineon BSC0906NS as the DC-to-DC converter to generate the +5V and +3.3V outputs. The BSC0906NS's rated continuous drain current is 40A at 100c and pulsed drain current is 252A. Drain source voltage is rated at 30V, and an RDS(on) value of 4.5 mΩ maximum and 3.8 mΩ typical. The cooling of those components is accomplished by things like the heatsink besides the main transformer, PSU enclosure's bottom side panel, and some thermal pads.
Meanwhile, there is a Weltrend WT7527V supervisor IC to realize over/under current and over/under voltage protection. An ANPEC APW7159C as PWM controller can be spotted here as well. More information about the parts mentioned in this review can be found from their respective datasheets from the manufacturer's website.
The modular cable sockets are soldered onto another daughterboard at the rear of the power supply unit. Having good soldering quality of those sockets is very important, since a significant amount of force will be applied on them when plugging or unplugging the connectors. The sockets in the NJ700 700W PSU have very good soldering quality, and I am sure that they can handle some abuse with no problem.
After inspecting the inside, there is no doubt the SilverStone Nightjar NJ700 700W is a quality power supply with Seasonic as its OEM. I can also see how it can be passively cooled. Firstly, all the components are well arranged for optimal heat dissipation. Secondly, the large number of metal heatsinks can guarantee the cooling of those high-power components. Thirdly, this product uses a lot of high-quality parts.
1. Introduction, Packaging, Specifications
2. Physical Look - Outside
3. Physical Look - Inside
4. Minor Tests and Conclusion