Power Supply Specification Guidelines  Intel® Server Board S2600CW Family TPS 
134    Revision 2.4 
Table 59. PWOK Signal Characteristics 
Open collector/drain output from power supply.  
Pull-up to VSB located in the power supply. 
Logic level low voltage, Isink=400uA 
Logic level high voltage, Isource=200µA 
Source current, PWOK = high 
pwok_on
pwok_off
 
A recommended implementation of the Power Ok circuits is shown below. 
Note: the Power Ok circuits should be compatible with 5V pull up resistor (>10k) and 3.3V pull 
up resistor (>6.8k). 
10.2.6.3  SMBAlert# Signal 
This signal indicates that the power supply is experiencing a problem that the user should 
investigate. This shall be asserted due to Critical events or Warning events. The signal shall be 
activated in case the critical component temperature reaches a warning threshold, general 
failure, over-current, over-voltage, under-voltage, or fan failure. This signal may also indicate 
the power supply is reaching its end of life or is operating in an environment exceeding the 
specified limits. 
This signal is to be asserted in parallel with LED turning solid Amber or blink Amber. 
Table 60. SMBAlert# Signal Characteristics 
Open collector/drain output from power supply.  
Pull-up to VSB located in system. 
Logic level low voltage, Isink=4 mA 
Logic level high voltage, Isink=50 µA 
Sink current, Alert# = low 
Sink current, Alert# = high 
Alert# rise and fall time