Page 3 - Physical Look - Inside
As we usually do, we opened up the SilverStone SX700-LPT 700W power supply to take a closer look at what is going on inside. Opening up this power supply will void your three year warranty, as the warranty seal covers one of the chassis screws. For your benefit, we voided our warranty on this unit, so you do not need to. There are zero user serviceable parts inside anyway. Removing the top shell from the SilverStone SX700-LPT 700W is easy, as it requires four screws to be removed; one at each corner on the side. Afterwards, you can slide apart the top and bottom shells to get inside. The OEM for the SilverStone SX700-LPT 700W is High Power Electronic Co., Ltd/Sirfa, which is the same manufacturer as some other SilverStone units, such as the SilverStone Strider Platinum ST75F-PT. The photo above shows an overhead view of its internal components. Build quality looks acceptable, and there does not seem to be any large globs of glue anywhere. This OEM does not have the greatest reputation compared to other OEMs such as Enhance or Seasonic, but we will see how this affects the build. Otherwise, there is a total of two large heatsinks, both of which are painted black.
The transient filter stage is the first input stage of any computer power supply, so we will take a closer look at this first. From here, there are two ferrite coils and one metal oxide varistor. A single X-capacitor and two Y-capacitors are placed at the AC receptacle, while another additional set of two X- and two Y-capacitors are found on the main board. In total, this is more than twice the amount of X and Y capacitors recommended, which is great to see. In addition, the MOV being present here is good, as they are intended to protect your power supply from AC line voltage spikes. A transient-voltage-suppression or TVS diode is located at this stage to help with suppressing voltage spikes, too.
On the primary side there is a single Rubycon capacitor. While it is completely shrink wrapped, further investigation reveals this is rated at 390uF at 420V. It has a temperature rating of 105c. It is great to see a Japanese-made capacitor here, as some cheaper units have capacitors made from Taiwan or China. In addition, budget power supplies have primary capacitors rated at a lower 85c temperature.
The active PFC circuit in the SilverStone SX700-LPT 700W is located on an add-in card. An Infineon 3PCS02 provides PFC control for this unit. Otherwise, other components in the active PFC circuitry were hard to get a closer look at, due to the pure compactness of the SFX-L power supply. However, again further research shoes both the two main switches and the active PFC parts are all SiGma Micro's SGF110N60W3 N-channel MOSFET. This transistor is rated to deliver 16A at 100 degrees Celsius continuously, with a maximum resistance of 0.11 ohm, and a typical resistance of 0.095 ohm. 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. A single Infineon IDH08G65C5 Schottky diode is also found in the active PFC circuit.
As for the secondary side, there are quite a few more Japanese capacitors made from Rubycon and Nippon Chemi-Con, including both the electrolytic and polymer capacitors. The electrolytic capacitors are all 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. The +12V output is regulated by an Infineon BSC014N04LS MOSFET. Unfortunately, these do not have any heatsinks attached. It would have probably been better to add a heatsink here, or use thermal padding to use the chassis as a heatsink. In addition, they are unlike most typical MOSFETs, as they have eight pins instead of the typical three. Drain source voltage is rated at 40V, with a continuous drain current of 100A at 25c. The -12V and standby rails are both each controlled by an Infineon IPD060N03L power transistor. These are rated at a continuous drain current of 50A at 100c, and a puled drain current of 350A. Drain source voltage is rated at 30V, and an RDS(on) value of 0.009 ohm maximum, and 0.0072 ohm typical. Another daughterboard can be found with the DC to DC converters, but once again, the MOSFETs are hard to get a read of. An ANPEC APW7159C dual channel synchronous buck PWM controller can be found here too. Finally, an Infineon ICE2HS01G PWM controller and a Silicon Touch PS223 protection IC can be found together. 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. This is where the modular cable sockets go. Layout of the output connectors can be found on the previous page. There is nothing too special, other than the fact there are a lot of cables running around here. The compactness of the SilverStone SX700-LPT 700W is one of the main reasons why this unit is a lot harder to build or inspect, but I have to say SilverStone and High Power have done a good job in ensuring quality is not sacrificed here. Soldering is pretty good, which is even more crucial on a smaller board like this. Component selection too is pretty great, with decent layout for cooling. Obviously, with a form factor like the SFX-L size, cooling is even more important.
Speaking of cooling, the last component to look at is an important one, as it draws in air to let all these small components breathe easy. This is a PowerYear 120mm fan, connected to the mainboard of the power supply. It should be noted this is a semi-passive power supply, as the fan only kicks in at higher loads. Further research of the Power Year PY-12015H12S proved fruitless, as not a whole lot of information can be found on these fans. It operates at 12V and 0.22A, offers sleeve bearings for quieter operation, and has a maximum speed of around 1700RPM.
1. Introduction, Packaging, Specifications
2. Physical Look - Outside
3. Physical Look - Inside
4. Minor Tests and Conclusion