OCZ ZT Series 650 W Power Supply Review

Power Distribution

The OCZ ZT Series 650 W uses a semi-synchronous design on the +12 V output: the direct rectification is performed by two MOSFETs, but the “freewheeling” part of the rectification is done by two Schottky rectifiers. The replacement of diodes with transistors is made in order to increase efficiency, but usually, all the diodes are replaced rather than only half, as in this case.

The +12 V output uses two QM6020AP MOSFETs, each one supporting up to 198 A at 25° C or 125 A at 100° C in continuous mode, or 350 A at 25° C in pulse mode, with a 3.8 mΩ RDS(on), and two PFR60L60CT Schottky rectifiers (60 A, 30 A per internal diode at 100° C, 0.65 V maximum voltage drop).

The +5 V output uses two PFR30L45CT Schottky rectifiers (30 A, 15 A per internal diode at 100° C, 0.52 V maximum voltage drop), which gives us a maximum theoretical current of 43 A or 214 W for this output.

The +3.3 V output uses two PFR20L45CT Schottky rectifiers (20 A, 10 A per internal diode at 120° C, 0.50 V maximum voltage drop), which gives us a maximum theoretical current of 29 A or 94 W for this output.

Figure 14: The +12 V transistors, +12 V rectifiers, +5 V rectifiers, and +3.3 V rectifiers

This power supply uses an ST9S424 monitoring integrated circuit. Unfortunately, the datasheet for this component is not available at the manufacturer’s website, so we can’t comment on the protections that this power supply actually supports.

Figure 15: Monitoring circuit

The electrolytic capacitors that filter the outputs are Japanese, from Chemi-Con, and are labeled at 105° C, as usual.