MAX5935CAX Maxim Integrated Products, MAX5935CAX Datasheet - Page 28

• Manufacturer Part Number: MAX5935CAX
• Description: Hot Swap & Power Distribution
• Manufacturer: Maxim Integrated Products

Specifications of MAX5935CAX

• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

Setting BCKOFF_ to 1 (Table 18) enables cadence
timing on each port, where the port backs off and waits
2.2s after each failed load discovery detection. The IEEE
802.3af standard requires a PSE that delivers power
through the spare pairs (midspan PSE) to have cadence
timing. A reset sets R14h = 0000XXXX, where X is the
logic AND of the MIDSPAN and AUTO input state prior to
a reset. BCKOFF_ can be changed by software at any
time while changes to the MIDSPAN and AUTO input
state during normal operation are ignored.
Quad Network Power Controller
for Power-Over-LAN
Table 15a. Mode Status
Table 16. Load Disconnect Detection Enable Register
Table 17. Detection and Classification Enable Register
28
CLASS_EN4
CLASS_EN3
CLASS_EN4
CLASS_EN3
DET_EN4
DET_EN3
DET_EN2
DET_EN1
DCD_EN4
DCD_EN3
DCD_EN2
DCD_EN1
ACD_EN4
ACD_EN3
ACD_EN2
ACD_EN1
SYMBOL
SYMBOL
______________________________________________________________________________________
ADDRESS = 14h
ADDRESS = 13h
MODE
00
01
10
11
BIT
BIT
7
6
5
4
3
2
1
0
7
6
5
4
3
2
1
0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Enable AC disconnect detection on port 4
Enable AC disconnect detection on port 3
Enable AC disconnect detection on port 2
Enable AC disconnect detection on port 1
Enable DC disconnect detection on port 4
Enable DC disconnect detection on port 3
Enable DC disconnect detection on port 2
Enable DC disconnect detection on port 1
Enable classification on port 4
Enable classification on port 3
Enable classification on port 2
Enable classification on port 1
Enable detection on port 4
Enable detection on port 3
Enable detection on port 2
Enable detection on port 1
DESCRIPTION
Semi AUTO
Shutdown
MANUAL
AUTO
TSTART[1,0] (Table 19) programs the startup timers.
Startup time is the time the port is allowed to be in current
limit during startup. TFAULT_[1,0] programs the fault
time. Fault time is the time allowable for the port to be in
current limit during normal operation. RSTR[1,0] pro-
grams the discharge rate of the TFAULT_ counter and
effectively sets the time the port remains off after an over-
current fault. TDISC[1,0] programs the load disconnect
detection time. The device turns off power to the port if it
fails to provide a minimum power maintenance signal for
longer than the load disconnect detection time (TDISC).
Set the bits in R16h to scale the TSTART, TFAULT, and
TDISC to a multiple of their nominal value specified in
the Electrical Characteristics table. R27h and R28h fur-
ther extend the programming range of these timers and
also increase the programming resolution.
When the MAX5935 shuts down a port due to an
extended overcurrent condition (either during startup or
normal operation), if RSRT_EN is set high, then the part
does not allow the port to power back on before the
restart timer (Table 19a) returns to zero. This effectively
DESCRIPTION
DESCRIPTION