Rainbow Electronics MAX5960 - Manual (Page 12)

MAX5959/MAX5960
Quad PCI Express, Hot-Plug Controllers
12 ______________________________________________________________________________________
Pin Description (continued)
PIN NAME FUNCTION
23 3.3SC-
Slot C 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.
24 3.3GC
Slot C 3.3V Gate-Drive Output. Connect 3.3GC to the gate of slot C’s 3.3V MOSFET. At power-up,
3.3GC is charged to 5.5V above the 3.3V supply by a constant current derived from V
12VIN . V 3.3GC ‘s
rise time is determined by the external gate capacitance.
25 FAULTC
Open-Drain Fault Output Signal. FAULTC latches active-low whenever slot C 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,
FAULTC must be reset by toggling the ONC input. If the fault
is in the auxiliary output, FAULTC must be reset by toggling both ONC and AUXONC. For the
autorestart version, FAULTC is reset when the part initiates the next power-on cycle.
26 PWRGDC
Open-Drain Power-Good Output. PWRGDC goes low 160ms after all outputs of slot C reach their final
value and the power MOSFETs are fully enhanced.
27,28 3.3AUXOC Slot C 3.3V Auxiliary Power-Supply Output
29, 30, 31,
69, 70, 71
3.3VAUXIN
3.3V Auxiliary Supply Input. 3.3VAUXIN is the input to a charge pump that drives the internal MOSFETs
connecting 3.3AUXIN to 3.3AUXO_. V
3.3AUXIN is also used to power the internal control logic and
analog references of the MAX5959/MAX5960 and must always be connected to a supply between 3V
and 3.6V. Bypass 3.3AUXIN with at least a 0.1µF capacitor to GND.
32, 33 3.3AUXOD Slot D 3.3V Auxiliary Power-Supply Output
34, 66 PGND Power Ground. Connect externally to GND.
35 PWRGDD
Open-Drain Power-Good Output. PWRGDD goes low 160ms after all outputs of slot D reach their final
value and the power MOSFETs are fully enhanced.
36 FAULTD
Open-Drain Fault Output Signal. FAULTD latches active-low whenever slot D 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,
FAULTD must be reset by toggling the OND input. If the fault
is in the auxiliary output, FAULTD must be reset by toggling both OND and AUXOND. For the
autorestart version, FAULTD is reset when the part initiates the next power-on cycle.
37 TIM
Overcurrent Timeout Programming Input. Connect a resistor between 500 Ω and 500kΩ from TIM to
GND to program t FAULT . Leave TIM unconnected for a default timeout of 11ms.
38 PORADJ
Power-On-Reset Programming Input. Connect a resistor between 500 Ω and 500kΩ from PORADJ to
GND to program the POR timing. Leave unconnected for a default value of 160ms. Connect PORADJ to
GND to completely skip the POR time delay for
PWRGD_ assertion.
39 GND Ground
40 12VIN
12V Supply Input. V 12VIN drives the gates of the MOSFETs connected to 3.3G_. 12VIN powers an
internal charge pump that drives the gates of the MOSFETs connected to 12G_. Bypass 12VIN with a
1µF capacitor to GND. See the Typical Application Circuit and Input Transients section.
41 12GD
Slot D 12V Gate-Drive Output. Connect 12GD to the gate of slot D’s 12V MOSFET. At power-up, V 12GD
is raised to the internal charge-pump voltage level by a constant current.
42 12SD-
Slot D 12V Negative Current-Sense Input. Connect 12SD- to the negative side of the current-sense
resistor using the Kelvin-sensing technique to ensure accurate current sensing.