max5957letnt Maxim Integrated Products, Inc., max5957letnt Datasheet - Page 13

• Manufacturer Part Number: max5957letnt
• Description: Triple Pci Express, Hot-plug Controllers
• Manufacturer: Maxim Integrated Products, Inc.

The MAX5957/MAX5958 triple hot-plug controllers are
designed for PCIe applications. The devices provide
hot-plug control for 12V, 3.3V, and 3.3V auxiliary sup-
plies for three PCIe slots. The MAX5957/MAX5958s’
logic inputs/outputs allow interfacing directly with the
system hot-plug-management controller or through an
SMBus with an external I/O expander. An integrated
debounced attention switch and present-detect signals
are included to simplify system design (Figure 1).
PIN
41
42
43
44
45
47
50
51
52
53
54
55
56
3.3AUXOA
3.3AUXOB
PWRGDA
PWRGDB
FAULTA
FAULTB
3.3SA+
3.3SB+
3.3SA-
3.3SB-
NAME
3.3GA
3.3GB
12GB
______________________________________________________________________________________
Triple PCI Express, Hot-Plug Controllers
Detailed Description
Slot A 3.3V Positive Current-Sense Input. Connect the positive side of the current-sense resistor to
3.3SA+ using the Kelvin-sensing technique to ensure accurate current sensing.
Slot A 3.3V Negative Current-Sense Input. Connect to the negative side of the sense resistor using
the Kelvin-sensing technique to ensure accurate current sensing.
Slot A 3.3V Gate-Drive Output. Connect 3.3GA to the gate of slot A’ s 3.3V MOSFET. At power-up,
V
V
Open-Drain Fault Output Signal. FAULTA latches active low whenever slot A outputs are shut down
due to a fault. A fault is either of:
• An overcurrent condition lasting longer than the overcurrent timeout.
• A device overtemperature condition.
If the fault is detected in the main outputs, FAULTA must be reset by toggling the ONA input. If the
fault is in the auxiliary output, FAULTA must be reset by toggling both ONA and AUXONA. For the
autorestart version, FAULTA is reset when the part initiates the next power-on cycle.
Open-Drain Power-Good Output. PWRGDA goes low 160ms after all outputs of slot A reach their
final value and the power MOSFETs are fully enhanced.
Slot A 3.3V Auxiliary Power-Supply Output
Slot B 3.3V Auxiliary Power-Supply Output
Open-Drain Power-Good Output. PWRGDB goes low 160ms after all outputs of slot B reach their
final value and the power MOSFETs are fully enhanced.
Open-Drain Fault Output Signal. FAULTB latches active low whenever the slot B outputs are shut
down due to a fault. A fault is either of:
• An overcurrent condition lasting longer than the overcurrent timeout.
• A device over temperature condition.
If the fault is detected in the main outputs, FAULTB must be reset by toggling the ONB input. If the
fault is in the auxiliary output, FAULTB must be reset by toggling both ONB and AUXONB. For the
autorestart version, FAULTB is reset when the part initiates the next power-on cycle.
Slot B 3.3V Gate-Drive Output. Connect 3.3GB to the gate of slot B’s 3.3V MOSFET. At power-up,
V
V
Slot B 3.3V Negative Current-Sense Input. Connect to the negative side of the sense resistor using
the Kelvin-sensing technique to ensure accurate current sensing.
Slot B 3.3V Positive Current-Sense Input. Connect the positive side of the current-sense resistor to
3.3SB+ using the Kelvin-sensing technique to ensure accurate current sensing.
Slot B 12V Gate-Drive Output. Connect 12GB to the gate of slot B’s 12V MOSFET. At power-up,
V
3.3GA
3.3GA
3.3GB
3.3GB
12GB
‘s rise time is determined by the external gate capacitance.
‘s rise time is determined by the external gate capacitance.
is raised to the internal charge-pump voltage level by a constant current.
is charged to 5.5V above the 3.3V supply by a constant current derived from V
is charged to 5.5V above the 3.3V supply by a constant current derived from V
The MAX5957/MAX5958 drive six external n-channel
MOSFETs to control the 12V and 3.3V main outputs.
The 3.3V auxiliary outputs are controlled through inter-
nal 0.2Ω n-channel MOSFETs. Internal charge pumps
provide a gate drive for the 12V outputs while the gate
drive of the 3.3V output is driven by the 12V input sup-
ply. The 3.3V auxiliary outputs are completely indepen-
dent from the main outputs with their own charge
pumps.
FUNCTION
Pin Description (continued)
12VIN
12VIN
.
.
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