NZXT E Series 850W PSU Review: An Analog Platform With Digital Enhancements

Teardown & Component Analysis

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.

This is a modified version of the analog Seasonic Focus Plus Gold platform featuring a digital controller that appears to be used alongside an analog one. We're not sure why both controllers are used, or what each of them handles.

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A full-bridge topology is used on the primary side, along with an LLC resonant converter. This is the typical scheme for high efficiency nowadays. On the secondary side, four FETs regulate the +12V rail while a couple of DC-DC converters handle the minor rails.

NZXT uses high-quality capacitors, and its cooling fan is the same one found in Seasonic's SSR-850FX. In fact, a number of the E850's parts mirror the SSR-850FX, including its bridge rectifiers, the boost diode in the APFC converter, the primary switching FETs, the APFC controller and analog resonant controller, the +12V FETs, the voltage regulation modules, the supervisor IC, and the parts composing the 5VSB regulation circuit.

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The first part of the transient filter is on a small PCB located right behind the AC receptacle. It consists of a couple of Y caps and one X cap, along with a CM02X that blocks current through the X cap's discharge resistor when AC voltage is connected. The EMI filter continues on the main PCB with two more Y caps and a single X one, two CM chokes, and an MOV.

An NTC thermistor protects against large inrush currents; it is supported by a bypass relay.

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The bridge rectifiers (GBU1506) are bolted onto a dedicated heat sink.

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The APFC converter uses two Infineon IPA60R190P6 FETs and a STMicroelectronics STTH8S06D boost diode. The bulk cap is provided by Hitachi and it has a capacity of 680uF (that's 30uF more than the SSR-850FX's bulk cap). NZXT's hold-up time exceeds the ATX spec's 17ms minimum, so the bulk capacitor's capacity is deemed sufficient.

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The APFC controller is installed on the main PCB's solder side, along with the LLC resonant controller. The first is a Champion CM6500UNX, while the second is the omnipresent CM6901. In addition to the analog controllers, we also find a Texas Instruments UCD3138064A digital controller capable of supporting this platform's primary and secondary sides. As a result, there's no way of knowing what the CM6901 and the UCD3138064A actually handle.

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The primary FETs include four UTC GPT13N50DGs (the SSR-850FX and SSR-750FX use four UTC GBT10N50ADGs) configured in a full bridge topology. An LLC resonant converter is also used for boosting efficiency.

This is the PSU's main transformer.

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On the secondary side, the +12V rail is rectified by four Nexperia PSMN2R6-40YS FETs, similar to Seasonic's SSR-750FX and SSR-850FX.

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Filtering caps on the secondary side are sourced from Chemi-Con and Nichicon. The E850 uses higher-quality electrolytic capacitors than the SSR-850FX; instead of Chemi-Con KZE caps, NZXT's PSU is equipped with Nichicon HE ones that have a much longer lifetime. Besides electrolytic caps, several FPCAP polymer caps are used as well.

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A couple of DC-DC converters are located on small vertical PCB, employing six Infineon BSC0906NS FETs and a single Anpec APW7159 PWM controller.

The supervisor IC is a Weltrend WT7527V. It supports OCP at +12V for up to two channels however it doesn't feature over-temperature protection. The latter is most likely implemented through another circuit.

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A number of FPCAP polymer caps on the front of the modular board provide an extra ripple suppression filter.

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The USB controller is a Microchip PIC16F1455.

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Seasonic's soldering quality is very good, just as we'd expect.

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The fan is made by Hong Hua and its model number is HA1225H12SF-Z. It features a fluid dynamic bearing and can reach high rotational speeds if needed. Unfortunately, the default silent profile is not particularly quiet according to our measurements. The E850 is actually pretty noisy compared to its competition.

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