MAX5952AEAX+ Maxim Integrated Products, MAX5952AEAX+ Datasheet - Page 20

• Manufacturer Part Number: MAX5952AEAX+
• Description: IC PSE CNTRLR FOR POE 36-SSOP
• Manufacturer: Maxim Integrated Products
• Type: Power Over Ethernet Controller (PoE)r

Specifications of MAX5952AEAX+

• Applications: Remote Peripherals (Industrial Controls, Cameras, Data Access)
• Internal Switch(s): No
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 36-BSOP (0.300", 7.5mm Width)
• Product: Controllers & Switches
• Supply Voltage (max): 5.5 V
• Supply Voltage (min): 1.71 V
• Power Dissipation: 941 mW
• Operating Temperature Range: - 40 C to + 85 C
• Mounting Style: SMD/SMT
• Supply Current: 4.8 mA
• Input Voltage: 60V
• Digital Ic Case Style: SSOP
• No. Of Pins: 36
• Uvlo: 28.5V
• Frequency: 400kHz
• Interface: I2C
• Termination Type: SMD
• Rohs Compliant: Yes
• Filter Terminals: SMD
• Controller Type: Power Over Ethernet PD
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

When CL_DISC (R17h[2]) is set to 0, high-power mode
is configured by setting the ICUT bits to any combina-
tion other than 000, 110, or 111 (note that 000 is the
default value for the IEEE standard limit). See Table 3
and the Register Map and Description section.
During startup and normal operation, an internal circuit
senses the voltage at OUT_ and reduces the current-
limit value when (V
function helps to reduce the power dissipation on the
FET. The current limit eventually reduces to 1/3 of I
when (V
power mode, the foldback starts when (V
10V (see Figure 3b). In high-power mode, the current
limit (I
when (V
Connect the gate of the external n-channel MOSFET to
GATE_. An internal 50µA current source pulls GATE_ to
(V
High-Power, Quad, PSE Controller
for Power-Over-Ethernet
Figure 3a. Foldback Current Characteristics
20
(V
EE
SENSE_
V
SU_LIM
______________________________________________________________________________________
+ 10V) to turn on the MOSFET. An internal 40µA
V
LIM
SU_LIM
- V
OUT
OUT
EE
/ 3
) is reduced up to 1/8 of its programmed value
)
_ - V
_ - V
EE
EE
) > 48V.
OUT
) > 48V (see Figure 3a). For high-
28V
_ - V
MOSFET Gate Driver
EE
) > 28V. The foldback
Foldback Current
High-Power Mode
48V
OUT
_ - V
(V
OUT_
EE
- V
LIM
EE
) >
)
current source pulls down GATE_ to V
MOSFET.
The pullup and pulldown current controls the maximum
slew rate at the output during turn-on or turn-off. Use
the following equation to set the maximum slew rate:
where C
DRAIN of the external MOSFET. Current limit and the
capacitive load at the drain control the slew rate during
startup. During current-limit regulation, the MAX5952
manipulates the GATE_ voltage to control the voltage at
SENSE_ (V
shoots the limit threshold (V
current increases with the amount of overshoot. The
maximum fast pulldown current is 100mA.
During turn-off, when the GATE voltage reaches a value
lower than 1.2V, a strong pulldown switch is activated
to keep the MOSFET securely off.
Figure 3b. Foldback Current Characteristics for High-Power
Mode
V
(V
SU_LIM
RS
V
SU_LIM
- V
EE
GD
/ 3
)
RS
is the total capacitance between GATE and
). A fast pulldown activates if V
∆
10V
V
∆
OUT
t
=
SU_LIM
I
GATE
C
GD
). The fast pulldown
48V
EE
to turn off the
(V
OUT_
RS
- V
over-
EE
)