MSI Z68A-GD80 (B3) Motherboard

Voltage Regulator

The CPU voltage regulator circuit of the Z68A-GD80 has 10 phases for the CPU main voltage (Vcc a.k.a. Vcore), two for the CPU VTT voltage (integrated memory controller and L3 memory cache), and one for the CPU VAXG voltage (integrated video controller). Therefore, it uses a “10+2+1” configuration.

Figure 8: Voltage regulator circuit

Figure 9: Voltage regulator circuit

This motherboard uses military-class components. Electronic components are available in two series, civilian and military. Military components are more expensive but have tighter tolerance and can withstand a wider range of temperature. All electrolytic capacitors used in the main voltage regulator circuit are SMD (surface mount device), also known as highly-conductive polymerized or simply Hi-c, but the other voltage regulators (memory, chipset, etc.) use solid capacitors. All coils on this motherboard are solid ferrite-core models, also known as SFC, Super Ferrite Choke, which, according to MSI, can provide up to 20% improvement in efficiency.

Each main phase is controlled by a Renesas R2J20652 integrated circuit (click here for a detailed description and here for its datasheet), which combines the three required transistors (“high side,” “low side,” and “driver”) in a single chip. It also allows the switching clock to be at 1 MHz, which allows efficiency to be over 90%. (Usually, voltage regulator circuits switch at 250 kHz.)

There are two phases for the memory voltage, using ferrite coils, solid capacitors, and two Renesas R2J20652 chips, and two phases for the chipset voltage, using ferrite coils, solid capacitors, and low-RDS(on) transistors (i.e., high-efficiency transistors). This is important, because some motherboard manufacturers build high-end voltage regulators for the CPU but use lower-quality parts on the other voltage regulators.

If you want to learn more about the voltage regulator circuit, please read our tutorial on the subject.

The motherboard has 10 LEDs for you to monitor the phases of the main CPU voltage.

Figure 10: Phase-monitoring LEDs