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Corsair SF450 PSU Review

Corsair enters the SFX PSU market with its new SF series consisting of two models at 450W and 600W capacities. Both power supplies are fully modular, promise high performance and come with 92mm fans to minimize noise output.

A Look Inside And Component Analysis

Parts Description

Before proceeding with this page, we strongly encourage you to a look at our PSUs 101 article, which provides valuable information about PSUs and their operation, allowing you to better understand the components we're about to discuss. Our main tools for disassembling PSUs are a Thermaltronics soldering and rework station, and a Hakko 808 desoldering gun.

Primary Side
Transient Filter4x Y caps, 2x X caps, 3x CM chokes, 1x MOV
Inrush ProtectionNTC Thermistor & Relay
Bridge Rectifier(s)1x GBU1508 (600V, 15A @ 115 °C)
APFC MOSFETs1x Alpha & Omega AOK42S60 (700V, 25A @ 100 °C, 0.099 ohm)
APFC Boost Diode1x CREE C3D04060A (600V, 4A @ 135 °C)
Hold-up Cap(s)1x Nippon Chemi-Con  (420V, 390uF, 2000h @ 105 °C, KMW)
Main Switchers2x Fairchild FCP104N60F (600V, 24A @ 100 °C, 104 mhm)
APFC ControllerChampion CM6500UNX & CM03X Green PFC controller
Switching ControllerChampion CM6901
TopologyPrimary side: Half-Bridge & LLC Resonant Converter Secondary side: Synchronous Rectification & DC-DC converters
Secondary Side
+12V MOSFETs4x Alpha & Omega AON6590 (40V, 100A @ 100 °C, 1.55 mohm @ 125 °C)
5V & 3.3VDC-DC Converters: 4x Infineon BSZ040N04LS G (40V, 40A @ 100 °C, 4 mohm) PWM Controller: APW7159
Filtering CapacitorsElectrolytics: 1x Nippon Chemi-Con (1000h @ 105 °C, KMG), Rubycon (105 °C) Polymers: Nippon Chemi-Con, CapXon (DC-DC converter)
Supervisor ICSITI PS229 (OVP, UVP, OCP, PG) & AS358M
Fan ModelCorsair NR092L (92mm, 12V, 0.22A, 3950 RPM, Rifle Bearing)
5VSB Circuit
Rectifier1x APS04N60H FET (620V, 2.2A @ 100 °C) 2x SVM1045V (45V, 10A @ 25 °C)
Standby PWM ControllerLeadtrend LD7750RGR
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The new SF units are made by Great Wall, a manufacturer that also builds Corsair's CS line. This OEM has proven that it can build good PSUs, and that's exactly the case here. Inside the SF450, we find high-quality components and a modern design. There's an LLC resonant converter on the primary side and synchronous rectification on the secondary side, where the FETs that regulate the +12V rail are installed on the solder side of the mainboard and cooled by the chassis. There is one large heat sink on the primary side that looks beefy enough to support this unit's semi-passive mode. As you might expect from a compact PSU, the double-sided PCB is densely populated with components.

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The AC receptacle is installed on a small PCB that also hosts the first part of the EMI filter, including two Y caps, a single X one and a CM choke. As usual, the second part of this filter is hosted on the main PCB and consists of two Y and a single X caps, two CM chokes and an MOV. The EMI filter is complete.

Right under the PFC input capacitor, responsible for filtering the high-frequency ripple that the bridge rectifier creates, is an electromagnetic relay used to bypass the NTC thermistor. This component provides protection against large inrush currents. The thermistor is located between the relay and the primary heat sink.

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The single bridge rectifier is a GBU1508, able to handle up to 15A of current.

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The APFC converter uses a single Alpha & Omega AOK42S60 FET and a CREE C3D04060A boost diode. The bulk cap is provided by Chemi-Con (420V, 390uF, 2000h @ 105 °C, KMW), and it has enough capacity to offer a hold-up time that easily meets ATX spec's requirements.

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The APFC controller is a Champion CM6500UNX, which is also supported by a CM03X Green PFC controller. Both ICs are installed on the mainboard's solder side.

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A couple of Fairchild FCP104N60F FETs are the primary switchers, arranged into a half-bridge topology (popular in high-efficiency PSUs). An LLC resonant converter is also used to boost efficiency through lossless switching. The resonant (and PWM) controller is a Champion CM6901, installed on the solder side of the mainboard along with a Si8233BD isolated driver. This driver is used by the main switching FETs, and it supports switching frequencies of up to 8MHz.

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The +12V rail is regulated by four Alpha & Omega AON6590 FETs, which are clearly overkill for a 450W PSU since each one can handle up to 100A at 100 °C. The filtering of this rail is done mostly by high-quality Chemi-Con polymer caps. Besides a tiny Chemi-Con KMG electrolytic cap we also find three Rubycon ones. At least one of these Rubycons is used by the 5VSB circuit.

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The minor rails are generated by a couple of DC-DC converters fed by the +12V rail. Each converter uses two Infineon BSZ040N04LS G FETs and the common PWM controller is an ANPEC APW7159. Several CapXon polymer caps are used for filtering these rails.

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Near the 5VSB transformer are two SVM1045V SBRs, and on the mainboard's solder side we find a SVM1045V FET and the standby PWM controller, a Leadtrend LD7750RGR.

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On the front side of the modular board, many polymer caps filter the PSU's outputs. Around back, a number of SMD components are installed.

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We're impressed by the soldering quality. Many interesting components are installed on this side. In addition to the ones we just mentioned, we also find the supervisor IC, a SITI PS229, which is supported by a AS358M op-amp. There are actually two AS358Ms, though only one of them is likely utilized by the unit's protection features.

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Corsair uses a 92mm rifle-bearing fan in both of its SF-series PSUs. The NR092L promises quiet operation even at higher speeds, thanks to its blades that purportedly increase airflow while keeping noise output as low as possible. The fan is supported by a semi-passive mode and a very relaxed ramp profile. We had to push the PSU hard to get its fan spinning at high speeds.

Aris Mpitziopoulos
Aris Mpitziopoulos is a Contributing Editor at Tom's Hardware US, covering PSUs.