Intel ATX12V - Manual (Page 24)

ATX12V Power Supply Design Guide
Version 2.0
24
Table 14. PS_ON# Signal Characteristics
Min. Max.
V
IL
, Input Low Voltage 0.0 V 0.8 V
I
IL
, Input Low Current (Vin = 0.4 V) -1.6 mA
V
IH
, Input High Voltage (Iin = -200 µA) 2.0 V
V
IH
open circuit, Iin = 0 5.25 V
Enable
Disable
PS_ON# Voltage
0.8 2.0 5.25 = Maximum Open-
Circuit Voltage
≥ 2.0 V
PS is
disabled
≤ 0.8 V
PS is
enabled
Hysteresis ≥ 0.3 V
Figure 7. PS_ON# Signal Characteristics
3.3.3. +5 VSB
+5 VSB is a standby supply output that is active whenever the AC power is present. It
provides a power source for circuits that must remain operational when the five main DC
output rails are in a disabled state. Example uses include soft power control, Wake on
LAN, wake-on-modem, intrusion detection, or suspend state activities.
The +5 VSB output should be capable of delivering a minimum of 2.0 A at +5 V ± 5% to
external circuits. The power supply must be able to provide the required power during a
"wake up" event. If an external USB device generates the event, there may be peak
currents as high as 2.5A lasting no more than 500mS.
Overcurrent protection is required on the +5 VSB output regardless of the output current
rating. This ensures the power supply will not be damaged if external circuits draw more
current than the supply can provide.