MAX5952 MAXIM [Maxim Integrated Products], MAX5952 Datasheet - Page 21
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MAX5952
Manufacturer Part Number
MAX5952
Description
High-Power, Quad, PSE Controller for Power-Over-Ethernet
Manufacturer
MAXIM [Maxim Integrated Products]
Datasheet
1.MAX5952.pdf
(50 pages)
Available stocks
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Part Number
Manufacturer
Quantity
Price
Company:
Part Number:
MAX5952AUAX+
Manufacturer:
PANASONIC
Quantity:
10 000
V
ranges from +3.0V to +5.5V and determines the logic
thresholds for the CMOS connections (SDAIN,
SDAOUT, SCL, AUTO, SHD_, A_). This voltage range
enables the MAX5952 to interface with a nonisolated
low-voltage microcontroller. The MAX5952 checks the
digital supply for compatibility with the internal logic.
The MAX5952 also features a V
(V
MAX5952 in reset and the ports shut off. Bit 0 in the
supply event register shows the status of V
(Table 12) after V
outputs reference to DGND. DGND and AGND must be
connected together externally. Connect DGND to
AGND at a single point in the system as close as possi-
ble to the MAX5952.
SHD_ shuts down the respective ports without using
the serial interface. Hardware shutdown offers an emer-
gency turn-off feature that allows a fast disconnect of
the power supply from the port. Pull SHD_ low to
remove power. SHD_ also resets the corresponding
events and status register bits.
The MAX5952 contains an open-drain logic output (INT)
that goes low when an interrupt condition exists. R00h
and R01h (Tables 6 and 7) contain the definitions of the
interrupt registers. The mask register R01h determines
events that trigger an interrupt. As a response to an inter-
rupt, the controller reads the status of the event register
to determine the cause of the interrupt and takes subse-
quent actions. Each interrupt event register also contains
a Clear on Read (CoR) register. Reading through the
CoR register address clears the interrupt. INT remains
low when reading the interrupt through the read-only
addresses. For example, to clear a startup fault on the
port 4 read address 09h (see Table 11). Use the global
pushbutton bit in register 1Ah (bit 7, Table 23) to clear
interrupts, or use a software or hardware reset.
The MAX5952 contains several undervoltage and over-
voltage protection features. Table 12 in the Register
Map and Description section shows a detailed list of
the undervoltage and overvoltage protection features.
An internal V
keeps the MOSFET off and the MAX5952 in reset until
V
nal V
ports when (V
DD
AGND
DDUVLO
supplies power for the internal logic circuitry. V
EE
- V
overvoltage (V
) of +2.0V. A V
EE
EE
exceeds 29V for more than 3ms. An inter-
AGND
undervoltage lockout (V
DD
______________________________________________________________________________________
has recovered. All logic inputs and
- V
EE_OV
EE
Overvoltage Protection
DDUVLO
) exceeds 60V. The digital
Hardware Shutdown
) circuit shuts down the
DD
Undervoltage and
undervoltage lockout
High-Power, Quad, PSE Controller
condition keeps the
Digital Logic
EEUVLO
Interrupt
DDUVLO
) circuit
DD
for Power-Over-Ethernet
supply also contains an undervoltage lockout
(V
undervoltage and overvoltage interrupts: V
age interrupt (V
(V
fault latches into the supply events register (Table 12),
but the MAX5952 does not shut down the ports with
V
Setting R13h[DCD_EN_] bits high enable DC load moni-
toring during a normal powered state. If V
across R
V
and asserts the LD_DISC_ bit of the corresponding port.
The MAX5952 features AC load disconnect monitoring.
Connect an external sine wave to OSC. The oscillator
requirements are:
1) Frequency x V
2) Positive peak voltage > +2V
3) Frequency > 60Hz
A 100Hz ±10%, 2V
+2.2V typical) is recommended.
The MAX5952 buffers and amplifies 3x the external
oscillator signal and sends the signal to DET_, where
the sine wave is AC-coupled to the output. The
MAX5952 senses the presence of the load by monitor-
ing the amplitude of the AC current returned to DET_
(see the Functional Diagram).
Setting R13h[ACD_EN_] bits high enable AC load dis-
connect monitoring during a normal powered state. If
the AC current peak at the DET_ input falls below I
for more than t
asserts the LD_DISC_ bit of the corresponding port.
I
An internal comparator checks for a proper amplitude
of the oscillator input. If the positive peak of the input
sinusoid falls below a safety value of 2V, OSC_FAIL
sets and the port shuts down. Power cannot be applied
to the ports when ACD_EN is set high and OSC_FAIL is
set high. Leave OSC unconnected or connect it to
DGND when not using AC-disconnect detection.
If the MAX5952 die temperature reaches +150°C, an
overtemperature fault generates and the MAX5952
shuts down. The MOSFETs turn off. The die tempera-
ture of the MAX5952 must cool down below 130°C to
remove the overtemperature fault condition. After a
thermal shutdown, the part is reset.
ACTH
EEUV
DCTH
DDUVLO
DDUV
, V
is programmable using R23h[0-3].
, for more than t
), and V
S
DDUV
) falls below the DC load disconnect threshold,
). The MAX5952 also features three other
, or V
DISC
DD
EEUV
P-P
P-P
DDOV
overvoltage interrupt (V
, the device turns off power and
= 200V
DC Disconnect Monitoring
AC Disconnect Monitoring
±5%, with +1.2V offset (V
), V
DISC
.
DD
, the device turns off power
P-P
undervoltage interrupt
Thermal Shutdown
x Hz ±15%
RS
EE
(the voltage
undervolt-
DDOV
PEAK
ACTH
). A
21
=