Rainbow Electronics MAX5958 - Manual (Page 16)

MAX5957/MAX5958
Triple PCI Express, Hot-Plug Controllers
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Table 2. Control Logic Truth Table
* PRES-DET_ high-to-low transition has a 4ms delay (t DEG ).
ON_ AUXON_ FON_ PRES-DET
12V_ AND 3.3V_
OUTPUTS
3.3VAUXO_AUXILIARY
OUTPUTS
X X Low X On On
X X High High Off Off
Low Low High Low* Off Off
High Low High Low* On Off
Low High High Low* Off On
High High High Low* On On
Figure 2. Power-Up Timing, No Fault
V ON_,TH
ON_, AUXON_
PWRGD_
FAULT_
12G_, 3.3G_
12VO_, 3.3VO_
3.3VAUXO_
V PGTH12
V PGTH3.3
V PGTH3.3AUX
3.3AUXIN
RISING
EDGE
PWRGD_ IS PULLED UP TO 3.3.
FAULT_ IS PULLED UP TO 3.3AUXIN.
t
POR_HL
Figure 3. 12V Power-Up Timing (Turn-On into Output
Overcurrent/Short Circuit)
FAULT_
3.3VAUXIN
RISING
EDGE
PWRGD_ IS PULLED UP TO 3.3VAUXO_.
FAULT_ IS PULLED UP TO 3.3VAUXIN.
A FAULT ON THE 3.3V OUTPUT OR 3.3VAUXO_ OUTPUT PRODUCES SIMILAR RESULTS.
V ON_,TH
ON_
2 x t FAULT
PWRGD_
12G_
12V OUTPUT
CURRENT
3.3VAUXO_
V
12ILIM,TH
R
SENSE