Seasonic SSR-650PX PSU Review: High Performance Without Breaking The Bank

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Teardown & Component Analysis

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General Data
Manufacturer (OEM)Seasonic
Platform ModelPX
Primary Side
Transient Filter4x Y caps, 2x X caps, 2x CM chokes, 1x MOV , 1x CM02X
Inrush ProtectionNTC thermistor & diode
Bridge Rectifier(s)2x GBU1506 (600V, 15A @ 100°C)
APFC MOSFETs2x Infineon IPP50R199CP (550V, 15A @ 100°C, 0.199Ω)
APFC Boost Diode1x STMicroelectronics STTH8S06D (600V, 8A @ 125°C)
Hold-up Cap(s)1x Nippon Chemi-Con (400V, 450uF, 2000h @ 105°C, CE)
Main Switchers4x Infineon IPP50R250CP (550V, 9A @ 100°C, 0.25Ω)
APFC ControllerChampion CM6500UNX
Resonant ControllerChampion CM6901T6X
TopologyPrimary side: Full-bridge & LLC resonant controller Secondary side: Synchronous rectification & DC-DC converters
Secondary Side
+12V MOSFETs4x Nexperia PSMN2R6-40YS (40V, 100A @ 100°C, 3.7mΩ @ 100°C)
5V & 3.3VDC-DC Converters: 6x Infineon BSC0906NS (30V, 40A @ 100°C, 4.5mΩ) PWM Controller: 1x Anpec APW7159
Filtering CapacitorsElectrolytics: Chemi-Con (1-5000 @ 105°C, KZE), Chemi-Con (4-10,000 @ 105°C, KY), W Polymers: Chemi-Con
Supervisor ICWeltrend WT7527V (OVP, UVP, OCP, SCP, PG)
Fan ModelHong Hua HA1225M12F-Z (120mm, 12V, 0.45A, 2050 RPM, fluid dynamic bearing)
5VSB Circuit
Standby PWM ControllerExcelliance EM8569C
RectifierP10V45SP SBR (45V, 10A @ 50% duty cycle)

This is a modern platform featuring a full bridge topology on the primary side, along with an LLC resonant converter for increased efficiency. The secondary side features a synchronous regulation scheme where four FETs regulate the +12V rail, while the minor rails are generated using a couple of DC-DC converters.

Seasonic doesn't make any compromises with its capacitor selection: Chemi-Con electrolytic and polymer caps are responsible for filtering the rails. The KZE line isn't one of Chemi-Con's best, but it's reliable enough for a mid-range power supply. All of the smaller caps belong to the KY line, which has a much longer lifetime. We don't have much information on the W-labeled caps. According to our sources, those are custom-built by Chemi-Con to customer specifications.

The first part of the EMI filter resides on the AC receptacle and includes two Y caps and one X one. There is also a CM02X discharge IC on the same board. The filter continues on the main PCB with two more Y caps, one X cap, two CM chokes, and an MOV.

The bridge rectifiers are overkill for a 650W PSU. Apparently Seasonic got a good deal on those GBU1506s, so there was no need to use lower-current parts. Strangely enough, the heat sink holding them is straight. In almost every other Seasonic PSU that we've torn down, that heat sink was leaning.

Two Infineon IPP50R199CP FETs are used in the APFC converter, along with an STMicroelectronics STTH8S06D boost diode. The bulk cap is provided by Chemi-Con. Although its capacity looks low, it delivers ample hold-up time. Champion manufactures the PFC controller (CM6500UNX), which is installed on the main PCB's solder side.

The primary switching FETs are four Infineon IPP50R250CPs, and their controller is a Champion CM6901T6X that also handles the switching frequency of the secondary side's +12V FETs.

An Excelliance EM8569C, the standby PWM controller, is semi-hidden under the APFC's heat sink. The 5VSB rail's rectifier is a P10V45SP SBR.

The image above shows the SSR-650PX's main transformer.

Four Nexperia PSMN2R6-40YSes serve as the +12V FETs. They're installed on the main PCB's solder side. Heat sinks right above them help with cooling.

Again, all electrolytic caps are provided by Chemi-Con. Seasonic also uses some polymer capacitors from Chemi-Con.

This daughterboard hosts the couple of VRMs that regulate the minor rails. In total, six Infineon BSC0906NS FETs are used, while the common PWM controller for both VRMs is an Anpec APW7159.

On the modular board's front side, several electrolytic and polymer Chemi-Con caps suppress ripple on the rails.

Seasonic's soldering quality is good. There are several interesting parts on this side of the PCB, including the APFC and resonant controllers, along with the Weltrend WT7527V supervisor IC.

The cooling fan uses a fluid dynamic bearing, and it comes from Hong Hua (HA1225M12F-Z). Corsair's CX450 (CWT edition) uses the same model number, though that fan employs a rifle bearing instead.

We opened both fans to verify that Seasonic's version uses a higher-quality bearing, and indeed it does.

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Contributing Editor

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

  • DookieDraws
    I won't put anything in my builds, or builds I do for others, other than a Seasonic PSU. Used them for years and have never had any issues. Not saying there isn't any other reliable brands out there, as I know there are, but I'm sticking with what has worked for me.
  • mlee 2500
    What a Coincidence! I bought this very same Seasonic 650PX Power Supply and just last night finally took it out of the box to prep for my new build...and here I find a review for it!!

    The author makes an excellent point that a 2nd modular EPS cable really should be standard these days. With motherboards now supporting USB 3.1, integrated WiFi, a whole slew of 2A fan/pump connectors and tons of other power-drawing features which hardly even existed a decade ago, a second EPS is quickly becoming the norm rather then the exception.

    In my case, with the very popular ASrock Taichi Z series motherboards which requires three connectors (1x24, 1x8, 1x4), I need to obtain a second additional 8pin to 2x4 modular cable. I just happened to contact Seasonic about that not an hour before seeing this review and learned that is their approved distributor and that such a cable costs about $5.00

    If you do need to buy an additional EPS cable, BE SURE TO GET THE ONE WITH THE INLINE CAPACITOR, for the newer SSR series!!

    It was interesting to learn from this article that providing a second EPS cable isn't really typical for most vendors 650W power supplies, which makes me feel better about being in that predicament with Seasonic. I was initially a bit disappointed, but then I've never had a Desktop mobo which required so many connectors before.

    All that being said this appears to be an outstanding power supply, a great value, and given that my previous modular Seasonic Power Supply is still running great after more then 6 years, I remain a Seasonic customer until proven I shouldn't be.
  • Aris_Mp
    I am insisting for quite some time for a second EPS connectors in high-end PSUs and your post clearly shows why. Thank you!