Compaq 164SX Power Requirements, Environmental Requirements, Power Supply DC Current Requirements

Power Requirements

2.1 Power Requirements

The AlphaPC 164SX motherboard has a total power dissipation of 90 W, excluding any plug-in PCI and ISA devices. Table 2–3lists the power requirement for each dc supply voltage.

The power supply must be ATX-compliant.

Table 2–3 Power Supply DC Current Requirements

Voltage/Tolerance	Current1
+3.3 V dc, ±5%	5.0 A
+5 V dc, ±5%	12.0 A
–5 V dc, ±5%	0.0 A
+12 V dc, ±5%	1.0 A
–12 V dc, ±5%	100.0 mA

1Values indicated are for an AlphaPC 164SX motherboard with an Alpha 21164PC microprocessor operating at 400 MHz, with 128MB SDRAM, excluding adapter cards and disk drives.

Caution: Fan sensor required. The 21164PC microprocessor cooling fan must drive an RPM indicator signal. If the airflow stops, the sensor on the motherboard detects that the RPM has stopped, and resets the system.

2.2 Environmental Requirements

The 21164PC microprocessor is cooled by a small fan blowing directly into the chip’s heat sink. The AlphaPC 164SX motherboard is designed to run efficiently by using only this fan. Additional fans may be necessary depending upon cabinetry and the requirements of plug-in cards.

The AlphaPC 164SX motherboard is specified to run within the environment listed in Table 2–4.

2–4Features