Introduction

Seasonic offers four models under their G series, 360 W, 450 W, 550 W, and 650 W, all featuring the 80 Plus Gold certification. Let’s see how the low-wattage 360 W model fared on our tests.

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Figure 1: Seasonic G-360 power supply

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Figure 2: Seasonic G-360 power supply

The Seasonic G-360 is only 5.5” (140 mm) deep, using a 120 mm ball-bearing fan on its bottom (ADDA AD1212MB-A70GL).

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Figure 3: Fan

The Seasonic G-360 doesn’t have a modular cabling system. All cables are protected with nylon sleeves, which come from inside the unit. This power supply comes with the following cables:

• Main motherboard cable with a 20/24-pin connector, 20.1” (51 cm) long
• One cable with two ATX12V connectors that together form an EPS12V connector, 21.6” (55 cm) long
• One cable with one six-pin connector for video cards, 22.4” (57 cm) long
• One cable with two SATA power connectors, 17.7” (45 cm) to the first connector, 5.9” (15 cm) between connectors
• One cable with two SATA power connectors, 13.8” (35 cm) to the first connector, 5.9” (15 cm) between connectors
• One cable with three standard peripheral power connectors, 16.9” (43 cm) to the first connector, 5.1” (13 cm) between connectors

All wires are 18 AWG, which is the correct gauge to be used, except for the +12 V (yellow) wires, which are thicker (16 AWG).

The number of connectors is perfect for a 360 W power supply. In fact, it comes with one connector for video cards, a feature not usually found on power supplies below 400 W.

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Figure 4: Cables

Let’s now take an in-depth look inside this power supply.

A Look Inside the Seasonic G-360

We decided to disassemble this power supply to see what it looks like inside, how it is designed, and what components are used. Please read our “Anatomy of Switching Power Supplies” tutorial to understand how a power supply works and to compare this power supply to others.

On this page we will have an overall look, and then in the following pages we will discuss in detail the quality and ratings of the components used.

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Figure 5: Top view

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Figure 6: Front quarter view

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Figure 7: Rear quarter view

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Figure 8: The printed circuit board

Transient Filtering Stage

As we have mentioned in other articles and reviews, the first place we look when opening a power supply for a hint about its quality, is its filtering stage. The recommended components for this stage are two ferrite coils, two ceramic capacitors (Y capacitors, usually blue), one metalized polyester capacitor (X capacitor), and one MOV (Metal-Oxide Varistor). Very low-end power supplies use fewer components, usually removing the MOV and the first coil.

In the transient filtering stage, this power supply is flawless, with one X capacitor, four Y capacitors, and one ferrite coil more than the minimum required.

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Figure 9: Transient filtering stage (part 1)

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Figure 10: Transient filtering stage (part 2)

On the next page, we will have a more detailed discussion about the components used in the Seasonic G-360.

Primary Analysis

On this page, we will take an in-depth look at the primary stage of the Seasonic G-360. For a better understanding, please read our “Anatomy of Switching Power Supplies” tutorial. 

This power supply uses one GBU10JL rectifying bridge, which is attached to an individual heatsink. This bridge supports up to 10 A at 100° C. In theory, you would be able to pull up to 1,150 W from a 115 V power grid. Assuming 80% efficiency, the bridge would allow this unit to deliver up to 1,380 W without burning itself out (or 1,553 W at 90% efficiency). Of course, we are only talking about this particular component. The real limit will depend on all the components combined in this power supply.

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Figure 11: Rectifying bridge

The active PFC circuit uses one IPP60R199CP MOSFET, which supports up to 16 A at 25° C or 10 A at 100° C in continuous mode (note the difference temperature makes) or 51 A at 25° C in pulse mode. These transistors present a 199 mΩ maximum resistance when turned on, a characteristic called RDS(on). The lower the number the better, meaning that the transistor will waste less power, and the power supply will have a higher efficiency.

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Figure 12: The active PFC diode and the active PFC transistor

The active PFC circuit is managed by an ICE3PCS01 active PFC controller.

The output of the active PFC circuit is filtered by one 270 µF x 420 V Japanese electrolytic capacitor from Hitachi, labeled at 105° C.

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Figure 13: Capacitor

In the switching section, two 18N50 MOSFETs are employed using a resonant configuration. Each transistor supports up to 18 A at 25° C or 11 A at 100° C in continuous mode or up to 72 A at 25° C in pulse mode, with a maximum RDS(on) of 220 mΩ.

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Figure 14: One of the switching transistors

The switching transistors are controlled by an ICE2HS01G controller.

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Figure 15: Resonant controller (left) and active PFC controller (right)

Let’s now take a look at the secondary of this power supply.

Secondary Analysis

As one would expect in a high-efficiency power supply, the Seasonic G-360 uses a synchronous design, where the Schottky rectifiers are replaced with MOSFETs. Also, the reviewed product uses a DC-DC design in its secondary. This means that the power supply is basically a +12 V unit, with the +5 V and +3.3 V outputs produced by two smaller power supplies connected to the main +12 V rail. Both designs are used to increase efficiency.

The +12 V output uses two PSMN2R6-40YS MOSFETs, each one supporting up to 100 A at 100° C in continuous mode, or up to 651 A at 25° C in pulse mode, with a maximum RDS(on) of 5.3 mΩ. These transistors are located on the solder side of the printed circuit board, using the power supply case as their heatsink. 

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Figure 16: The +12 V transistors

As explained, the +5 V and +3.3 V outputs are produced by two DC-DC converters, which are situated on a single printed circuit board located in the secondary section of the power supply. The converters are controlled by an APW7159 integrated circuit, and each converter uses a pair of PH7030AL MOSFETs. Each transistor supports up to 76 A at 25° C or 53 A at 100° C in continuous mode and up to 260 A at 25° C in pulse mode, with a maximum RDS(on) of 7 mΩ.

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Figure 17: The DC-DC converters

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Figure 18: The DC-DC converters

The outputs of the power supply are monitored by an HY510N integrated circuit, which only supports over voltage (OVP) and under voltage (UVP) protections.

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Figure 19: Monitoring circuit

The electrolytic capacitors available in the secondary are also Japanese, from Chemi-Con and Rubycon, and labeled at 105° C, as usual. A few solid capacitors are also used.

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Figure 20: Capacitors

Power Distribution

In Figure 21, you can see the power supply label containing all the power specs.

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Figure 21: Power supply label

As you can see, there is only one +12 V rail, so there is not much to talk about here.

How much power can this unit really deliver? Let’s find out.

Load Tests

We conducted several tests with this power supply, as described in the article, “Hardware Secrets Power Supply Test Methodology.”

First, we tested this power supply with five different load patterns, trying to pull around 20%, 40%, 60%, 80%, and 100% of its labeled maximum capacity (actual percentage used listed under “% Max Load”), watching the behavior of the reviewed unit under each load. In the table below, we list the load patterns we used and the results for each load.

If you add all the powers listed for each test, you may find a different value than what is posted under “Total” below. Since each output can have a slight variation (e.g., the +5 V output working at 5.10 V), the actual total amount of power being delivered is slightly different than the calculated value. In the “Total” row, we are using the real amount of power being delivered, as measured by our load tester.

The +12VA and +12VB inputs listed below are the two +12 V independent inputs from our load tester. During this test, the +12VA and +12VB inputs were connected to the power supply’s single +12 V rail. (The +12VB input was connected to the power supply EPS12V connector.)

Input	Test 1	Test 2	Test 3	Test 4	Test 5
+12VA	2.5 A (30 W)	5 A (60 W)	7 A (84 W)	9.5 A (114 W)	11.5 A (138 W)
+12VB	2.5 A (30 W)	5 A (60 W)	7 A (84 W)	9.5 A (114 W)	11.5 A (138 W)
+5 V	1 A (5 W)	2 A (10 W)	4 A (20 W)	6 A (30 W)	8 A (40 W)
+3.3 V	1 A (3.3 W)	2 A (6.6 W)	4 A (13.2 W)	6 A (19.8 W)	8 A (26.4 W)
+5VSB	1 A (5 W)	1.5 A (7.5 W)	2 A (10 W)	2.5 A (12.5 W)	3 A (15 W)
-12 V	0.5 A (6 W)	0.5 A (6 W)	0.5 A (6 W)	0.5 A (6 W)	0.5 A (6 W)
Total	74.8 W	149.5 W	217.6 W	295.8 W	362.4 W
% Max Load	20.8%	41.5%	60.4%	82.2%	100.7%
Room Temp.	45.1° C	45.0° C	44.8° C	44.8° C	45.0° C
PSU Temp.	47.0° C	46.5° C	46.2° C	45.3° C	46.5° C
Voltage Regulation	Pass	Pass	Pass	Pass	Pass
Ripple and Noise	Pass	Pass	Pass	Pass	Pass
AC Power	85.3 W	166.3 W	243.0 W	332.0 W	414.2 W
Efficiency	87.7%	89.9%	89.5%	89.1%	87.5%
AC Voltage	114.8 V	114.0 V	112.8 V	112.7 V	111.5 V
Power Factor	0.987	0.994	0.996	0.996	0.997
Final Result	Pass	Pass	Pass	Pass	Pass

The 80 Plus Gold certification guarantees minimum efficiencies of 87% at 20% load, 90% at 50% load, and 87% at 100% load. In our tests, the Seasonic G-360 met these requirements at high temperatures, which is terrific.

All positive voltages were closer to their nominal values (3% regulation) during all tests. The -12 V output was outside this tighter range, but was still inside the allowed range. The ATX12V specification states that positive voltages must be within 5% of their nominal values, and negative voltages must be within 10% of their nominal values.

Let’s discuss the ripple and noise levels on the next page.

Ripple and Noise Tests

Voltages at the power supply outputs must be as “clean” as possible, with no noise or oscillation (also known as “ripple”). The maximum ripple and noise levels allowed are 120 mV for +12 V and -12 V outputs, and 50 mV for +5 V, +3.3 V and +5VSB outputs. All values are peak-to-peak figures. We consider a power supply as being top-notch if it can produce half or less of the maximum allowed ripple and noise levels.

The Seasonic G-360 provided relatively low ripple and noise levels, as you can see in the table below.

Input	Test 1	Test 2	Test 3	Test 4	Test 5
+12VA	23.2 mV	28.2 mV	31.0 mV	39.0 mV	46.4 mV
+12VB	18.6 mV	22.6 mV	27.6 mV	34.4 mV	40.2 mV
+5 V	10.4 mV	13.4 mV	14.2 mV	22.0 mV	25.8 mV
+3.3 V	10.2 mV	14.2 mV	16.2 mV	20.6 mV	24.8 mV
+5VSB	11.0 mV	11.4 mV	14.8 mV	16.2 mV	17.6 mV
-12 V	28.4 mV	34.2 mV	40.6 mV	52.8 mV	77.2 mV

Below you can see the waveforms of the outputs during test five.

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Figure 22: +12VA input from load tester during test five at 362.4 W (46.4 mV)

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Figure 23: +12VB input from load tester during test five at 362.4 W (40.2 mV)

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Figure 24: +5V rail during test five at 362.4 W (25.8 mV)

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Figure 25: +3.3 V rail during test five at 362.4 W (24.8 mV)

Let’s see if we can pull more than 360 W from this unit.

Overload Tests

Below you can see the maximum we could pull from this power supply. The objective of this test is to see if the power supply has its protection circuits working properly. This unit passed this test, since it shut down when we tried to pull more than what is listed below. During this test, noise and ripple levels increased to around 60 mV at +12 V outputs, half of the maximum allowed, while noise and ripple levels at +5 V and +3.3 V remained about the same. All outputs were still inside 3% of their nominal values.

Input	Overload Test
+12VA	15 A (180 W)
+12VB	15 A (180 W)
+5 V	8 A (40 W)
+3.3 V	8 A (26.4 W)
+5VSB	3 A (15 W)
-12 V	0.5 A (6 W)
Total	442.8 W
% Max Load	123.0%
Room Temp.	44.1° C
PSU Temp.	47.7° C
AC Power	513.1 W
Efficiency	86.3%
AC Voltage	111.1 V
Power Factor	0.997

Main Specifications

The main specifications for the Seasonic G-360 power supply include:

• Standards: NA
• Nominal labeled power: 360 W
• Measured maximum power: 442.8 W at 44.1° C
• Labeled efficiency: 80 Plus Gold certification; 87% minimum at light (20%) and full loads and 90% minimum at typical (50%) load
• Measured efficiency: Between 87.5% and 89.9%, at 115 V (nominal, see complete results for actual voltage)
• Active PFC: Yes
• Modular Cabling System: Yes
• Motherboard Power Connectors: One 20/24-pin connector and two ATX12V connectors that together form an EPS12V connector
• Video Card Power Connectors: One six-pin connector
• SATA Power Connectors: Four on two cables
• Peripheral Power Connectors: Three on one cable
• Floppy Disk Drive Power Connectors: None
• Protections (as listed by the manufacturer): Over voltage (OVP), under voltage (UVP), over power (OPP), and short-circuit (SCP) protections
• Are the above protections really available? Yes.
• Warranty: Five years
• More Information: http://www.seasonicusa.com
• Average Price in the U.S.*: USD 60.00

* Researched at Newegg.com on the day we published this review.

Conclusions

The Seasonic G-360 power supply is targeted to the savvy user who wants a low-wattage, high-quality unit. It provides excellent voltage regulation, low noise and ripple levels, and superb efficiency. The cable configuration is perfect for the labeled wattage.

The only problem is convincing the average user that 360 W is more than enough for most entry-level and mainstream PCs… Unfortunately, people tend to think that more wattage is better, which is not the case. Buying a high-wattage unit for an entry-level or mainstream PC is a waste of money, because you can buy a cheaper unit that will do the same job. Also, a high-wattage power supply installed on a mainstream PC won’t be providing its highest efficiency, which translates into a higher electricity bill.