Seasonic Reveals Its First Titanium PSU: The Prime

Seasonic decided to join the Titanium efficiency club rather late, however, the result looks like it was worth the long wait. The Prime series with Titanium efficiency will soon hit the market.

Seasonic's competitors have already released two high capacity Titanium units, most likely in an effort to steal the spotlight, since such powerful PSUs with over 1.2 kW capacities aren't very popular among users. On the other hand, Seasonic chose to enter the Titanium market with lower capacity PSUs, which will cover the needs of many more users.

The Prime series consists of four Titanium PSUs with capacities ranging from 650W to 1 kW. The same line will also include two fanless PSUs, featuring 550W and 400W capacity and Titanium efficiency, along with several Platinum units with capacities ranging from 550W to 1200W.

With the Prime product line being the flagship of Seasonic's consumer PSU portfolio, the company's new line, called Focus, comes next. The Focus line will have two Platinum units with 650W and 550W capacity and four Gold PSUs with capacities from 450W to 750W. It looks like the Focus units will replace the existing G-series models.

Besides commercial PSUs, Seasonic will also release several industrial units in 2016, which will feature high efficiency and digital control. We expected to see a digital commercial PSU from Seasonic, but we got an industrial digital PSU instead. In any case, this means that the company is working on digital control circuits, so it will also use this technology in its commercial platforms.

The technical specifications and features of the Seasonic SSR-850TD are listed below, as a reference.

Seasonic SSR-850TD - Features And Specifications
Max. DC Output 850 W
PFC Active PFC
Efficiency 80 Plus Titanium
Modular Yes (fully)
Intel Haswell Ready Yes
Operating temperature 0°C ~ 50°C
Protections Over Voltage Protection
Under Voltage Protection
Over Current Protection
Short Circuit Protection
Over Power Protection
Over Temperature Protection
Cooling 120 mm Dual Ball-Bearing Fan (9S1212M407)
Semi-passive operation Yes (Selectable)
Dimensions 150 mm (W) x 87 mm (H) x 170 mm (D)
Weight 2.0 kg
Compliance ATX12V v2.4, EPS 2.92

All Prime PSUs are fully modular, can deliver their full power at up to 50°C and are equipped with all necessary protection features. As you can see from the table above, the dimensions of the 850W unit are compact and a mid-speed Sanyo Denki fan was used for its cooling. Seasonic also provided a semi-passive operation, which can be disabled, should the user want the fan to spin at all times.

According to Seasonic, all Prime PSUs will have an extra long hold-up time, which will exceed 30 ms. We should remind you that ATX spec requires for 17 ms minimum hold-up time and at least 16 ms Power_OK hold-up time. Moreover, the Prime units will feature a very tight load regulation, meaning that their DC outputs will have minimal deviations throughout all load ranges.

The Hybrid Mode selection switch is installed at the front of the PSU, where it is easily accessible.

At the sides of the PSU we find Seasonic's logo and a set of stickers depicting the series name along with the efficiency level of the PSU. The design of the vent on the sides looks really nice and reminds us of a sports car.

We couldn't resist and took a peek at the PSU's internals, where the design is clear and there is enough space between the parts installed on the PCB in order to offer adequate airflow, which will keep the temperatures at low levels. Seasonic minimized the use of cables inside the PSU in an effort to reduce energy loss and block less of the cooling of crucial components, like the secondary side filtering capacitors.

In the following table you will find the parts that we were able to identify inside the 850W Seasonic Prime unit.

Primary Side
Transient Filter4x Y caps, 2x X caps, 2x CM chokes, 1x MOV
Inrush ProtectionNTC Thermistor & Relay
Bridge Rectifier(s)2x Vishay LVB2560 (600V, 25A @ 105°C)
APFC MOSFETS2x Infineon IPP50R140CP (550V, 15A @ 100°C, 0.14 Ohm)
APFC Boost Diode1x SCS110AG (600V, 10A @ 117°C)
Hold-up Cap(s)2x Nippon Chemi-Con (420V, 680uF and 470uF, 1150uF combined, 2000h @ 105°C, KMR)
Main Switchers4x Infineon IPP50R140CP (550V, 15A @ 100°C, 0.14 Ohm)
APFC Controller-
Switching Controller-
TopologyPrimary side: Full-Bridge & LLC Resonant Converter
Secondary side: Synchronous Rectification & DC-DC converters
Secondary Side
+12V MOSFETS4x Fairchild FDMS045N04B 
5V & 3.3V2x DC-DC Converters
Filtering CapacitorsElectrolytics: Nippon Chemi-Con (105°C, KY, KZE, KZH), Rubycon (105°C, YXG)
Polymers: Nippon Chemi-Con, FPCAP
Supervisor ICWeltrend WT7527 (OVP, UVP, OCP, SCP)
Fan ModelSanyo Denki, San Ace 120 - 9S1212M407 (120mm, 12 V, 0.13 A, 1850RPM, Double Ball-Bearing)
5VSB Circuit
Rectifier1x STF6N65K3
Buck ConverterLSP5523

In the primary side, Seasonic used bridge rectifiers, while the Super Flower and Flextronics (Corsair) high-capacity Titanium units utilize a bridge-less design. A full-bridge topology along with an LLC resonant converter can also be found in the primary side, while in the secondary side the +12V FETs are installed on the solder side of the mainboard. All filtering caps are Japanese, provided by Chemi-Con, Rubycon and FPCAP and besides electrolytics, polymers are also used.

The cooling fan is a double ball-bearing Sanyo Denki fan, which promises a long lifetime. Its model number is 9S1212M407 and its max speed is 1850 RPM.

Aris Mpitziopoulos is a Contributing Editor for Tom's Hardware, covering Power Supplies. Follow us on Twitter @tomshardware, on Facebook and on Google+.

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  • turkey3_scratch
    Companies are producing Titanium units out the wazoo! Sick looking fan grill. And I'm thrilled Seasonic is releasing great 450W-850W units. I'm tired of $400 1250W units.

    Also, lots of polymer caps! Things are getting better in the PSU world.
  • BadActor
    Man, if they don't charge an arm and a leg for the lower wattage variant's, they could sell millions.
  • turkey3_scratch
    2109598 said:
    Man, if they don't charge an arm and a leg for the lower wattage variant's, they could sell millions.

    Yep, but chances they are, they're going to sell an arm and a leg.