Datasheet

Threshold Windows
PGOOD Threshold
PGOOD Threshold
3.3 V
3.3 VAUX
Rails
12 V Rails
3.0 V
2.9 V
2.7 V
2.5 V
11.0 V
10.8 V
10.2 V
9.7 V
Sense resistor
voltage
45 mV
65 mV
Fault
time
12 V Gate
3.3 V
Gate
Depends on
Gate Capacitor
Fault without fast trip
0 mV
The fault normally is one
or the other, but not both.
Threshold
45 to 55 mV
C
FILTER
TPS2363
www.ti.com SLUS680B –JANUARY 2006–REVISED JANUARY 2010
Fault
Faults can occur on any of the input supplies, 3.3-V VAUX (VAUXINA/B), 3.3-V (SH33H), and 12-V (SH12A/B).
These inputs are monitored for under-voltage and issue a FAULTA/B if the power segment is commanded on
when it is out of range. VAUXINA/B UVLO causes a power on reset that clears the FAULTA/B.
The SlotA/B voltages (hot plug output voltages) are also monitored for under-voltage. The first indication of a slot
fault is normally when PGOODA/B de-asserting because the output voltage is below the threshold when the
controller starts to current limit. If the current limit is disabled, the FAULT will be the first indication. Figure 1
shows the threshold for PGOOD.
If the fault is above the under-voltage but an over-current condition exists, the FAULTA/B active will be the first
indication. Figure 2 shows a normal over current trip.
The TPS2363 will current limit the output to the slot and continue for the user defined fault time. If the fault
persists, TPS2363 turns off the SlotA/B power and sets the FAULTA/B output. The current limit can be disabled
by the SMBus. The FAULTA/B is reset by turning off the AUXENA/B or ONA/B pin in direct mode. The SMBus
can be used to read the fault information. The slot status byte is defined in the SMBus Register Information
Section, register STATA/B.
Figure 1. PGOOD Threshold, Grey Area is the PCIExpress CEM 1.1 Standard
Figure 2. Fault Without Fast Trip
Copyright © 2006–2010, Texas Instruments Incorporated Submit Documentation Feedback 13
Product Folder Link(s): TPS2363