MAX5952AUAX+ Maxim Integrated Products, MAX5952AUAX+ Datasheet - Page 19

• Manufacturer Part Number: MAX5952AUAX+
• Description: IC PSE CNTRLR FOR POE 36-SSOP
• Manufacturer: Maxim Integrated Products
• Type: Power Over Ethernet Controller (PoE)r

Specifications of MAX5952AUAX+

• Applications: Remote Peripherals (Industrial Controls, Cameras, Data Access)
• Internal Switch(s): No
• Operating Temperature: 0°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 36-BSOP (0.300", 7.5mm Width)
• Product: PoE / LAN Solutions
• Supply Voltage (max): 60 V
• Supply Voltage (min): 32 V
• Power Dissipation: 941 mW
• Operating Temperature Range: 0 C to + 85 C
• Mounting Style: SMD/SMT
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

A sense resistor R
V
conditions, the voltage across R
the threshold V
internal current-limiting circuit regulates the GATE volt-
age, limiting the current to I
transient conditions, if V
than 1V, a fast pulldown circuit activates to quickly
recover from the current overshoot. During startup, if
the current-limit condition persists, when the startup
timer, t
STRT_FLT_ bit is set. In the normal powered state, the
MAX5952 checks for overcurrent conditions as deter-
mined by V
counter sets the maximum allowed continuous overcur-
rent period. The t
exceeds V
when V
for the t
short-duration overcurrents. When the counter reaches
the t
asserts the IMAX_FLT_ bit. For a continuous overstress,
a fault latches exactly after a period of t
Figure 2. PGOOD Timing
EE
PGOOD
monitors the load current. Under normal operating
FAULT
POK
START
RS
FAULT
drops below V
FLT_LIM
limit, the MAX5952 powers off the port and
FLT_LIM
, times out, the port shuts off, and the
counter allows for detecting repeated
SU_LIM
______________________________________________________________________________________
FAULT
S
and decreases at a slower pace
t
= ~88% of V
PGOOD
connected between SENSE_ and
. If V
RS
counter increases when V
Overcurrent Protection
FLT_LIM
LIM
exceeds V
RS
= V
S
exceeds V
. A slower decrement
(V
High-Power, Quad, PSE Controller
SU_LIM
SU_LIM
RS
) never exceeds
SU_LIM
FAULT
. The t
/ R
SU_LIM
. V
S
by more
. During
SU_LIM
FAULT
, an
RS
for Power-Over-Ethernet
is programmable through the ICUT registers R2Ah[6:4],
R2Ah[2:0], R2Bh[6:4], R2Bh[2:0], and the IVEE bits in
register R29h[1:0]. See the High-Power Mode section
for more information on the ICUT register.
After power-off due to an overcurrent fault, and if the
RSTR_EN bit is set, the t
reset but starts decrementing at the same slower pace.
The MAX5952 allows the port to be powered on only
when the t
automatic duty-cycle protection to the external MOS-
FET avoiding overheating.
The MAX5952 continuously flags when the current
exceeds the maximum current allowed for the class as
indicated in the CLASS status register. When class
overcurrent occurs, the MAX5952 sets the IVC bit in
register R09h.
The ICUT register determines the maximum current lim-
its allowed for each port of the MAX5952. The 3 ICUT
bits (R2Ah[6:4], R2Ah[2:0], R2Bh[6:4], and R2Bh[2:0])
allow programming of the current-limit and overcurrent
thresholds in excess of the IEEE standard limit (see
Tables 34a, 34b, and 34c). The ICUT registers can be
written to directly through the I
CL_DISC (R17h[2]) is set to 0 (see Table 3). In this
case, the current limit of the port is configured regard-
less of the status of the classification.
By setting the CL_DISC bit to 1, the MAX5952 automati-
cally sets the ICUT register based upon the classifica-
tion result of the port. See Table 3 and the Register
Map and Description section.
Table 3. Automatic ICUT Programming
CL_DISC
0
1
1
1
ICUT Register and High-Power Mode
FAULT
CLASSIFICATION
counter is at zero. This feature sets an
RESULT
PORT
Any
0, 3
1
2
FAULT
timer is not immediately
2
C interface when
RESULTING ICUT
User programmed
REGISTER BITS
ICUT = 110
ICUT = 111
ICUT = 000
ICUT Register
19