PC Hardware in a Nutshell, 3rd Edition

TFX12V Power Supply Specifications

TFX12V is the newest standard power supply form factor. Like SFX/SFX12V, TFX12V is derived from ATX/ATX12V. TFX12V power supplies have a long, narrow physical shape that is optimized for small and low-profile microATX and FlexATX systems. TFX12V has an improved airflow design that allows the power supply fan to exhaust air from the area of the motherboard occupied by the processor, chipset, and other heat-generating components. TFX12V also uses fan speed control and other techniques for reduced noise relative to other power supply types. The TFX12V Power Supply Design Guide Version 1.01 defines the TFX12V voltage rails and tolerances shown in Table 26-9. A TFX12V 1.01-compliant power supply must provide these voltages with these tolerances or better.

Table 26-9. TFX12V power supply voltage rails and tolerances

Voltage rail	Tolerance	Vmin	Vnom	Vmax
+3.3VDC	±5%	+3.14V	+3.30V	+3.47V
+5VDC	±5%	+4.75V	+5.00V	+5.25V
+5VSB	±5%	+4.75V	+5.00V	5.25V
+12VDC	±5%	+11.40V	+12.00V	+12.60V
+12VDC (peak load)	±10%	+10.80V	+12.00V	+13.20V
-12VDC	±10%	-10.80V	-12.00V	-13.20V

The TFX Power Supply Design Guide Version 1.01 defines two TFX12V configurations, shown in Table 26-10. For both TFX12V power supplies, the combined output of the +3.3VDC and +5VDC rails is less than 61W.

Table 26-10. Typical power distribution for TFX12V power supplies

	180W TFX12V			220W TFX12V
Voltage rail	Amin	Amax	Apeak	Amin	Amax	Apeak