Specifications

17 January 1997 – Subject to Change
Power and Environmental Requirements 3–1
3
Power and Environmental Requirements
This chapter describes the AlphaPC 164 power and environmental requirements, and
physical board parameters.
3.1 Power Requirements
The AlphaPC 164 derives its main dc power from a user-supplied power supply. The
board has a total power dissipation of 116 W, excluding any plug-in PCI and ISA
devices. An onboard +5 V to +2.5 V dc-to-dc convertor is designed to handle 15 A of
current. Table 3–1 lists the power requirement for each dc supply voltage.
The power supply must supply a dcok signal to the system reset logic. Refer to
Section 4.7, and schematic pages pc164.29 and pc164.30 for additional information.
Caution:
Fan Sensor Required
The 21164 cooling fan must have a built-in sensor that will drive a signal
if the airflow stops. The sensor is connected to AlphaPC 164 board con-
nector J21. When the signal is generated, it resets the system.
1
Values indicated are for an AlphaPC 164 (64MB DRAM) excluding adapter cards and
disk drives.
Table 3–1 Power Supply DC Current Requirements
Voltage Current
1
+3.3 V dc 5.0 A
+5 V dc 12.0 A
–5 V dc 0 A
+12 V dc 1.0 A
–12 V dc 100.0 mA