MAX5935CAX Maxim Integrated Products, MAX5935CAX Datasheet - Page 13

• 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

over-current detection function enables system power
management where it detects a PD that draws more
current than the allowable amount for its class. The
MAX5935’s extensive programmability enhances sys-
tem flexibility and allows for uses in other applications.
The MAX5935 has four different operating modes: auto
mode, semi-auto mode, manual mode, and shutdown
mode (see the Operation Modes section). A special
Watchdog feature allows the hardware to gracefully
take over control if the software/firmware crashes. A
cadence timing feature allows the MAX5935 to be used
in midspan systems.
The MAX5935 provides input undervoltage lockout,
input undervoltage detection, input overvoltage lockout,
overtemperature protection, output voltage slew-rate
limit during startup, power-good status, and fault sta-
tus. The MAX5935’s programmability includes gate-
charging current, current-limit threshold, startup
timeout, overcurrent timeout, autorestart duty cycle,
PD-disconnect AC-detection threshold, and PD-discon-
nect detection timeout.
The MAX5935 communicates with the system micro-
controller through an I
MAX5935 features separate input and output data lines
(SDAIN and SDAOUT) for use with optocoupler isola-
tion. The MAX5935 is a slave device. Its four address
inputs allow 16 unique MAX5935 addresses. A sepa-
rate INT output and four independent shutdown inputs
(SHD_) allow fast interrupt signals between the
MAX5935 and the microcontroller. A RESET input
allows hardware reset of the device.
Reset is a condition the MAX5935 enters following any
of the following conditions:
•
•
•
•
During a reset, the MAX5935 resets its register map to
the Reset state as shown in Table 30 and latches in the
state of AUTO (pin 35) and MIDSPAN (pin 2). During
normal operation, changes at the AUTO and MIDSPAN
inputs are ignored. While the condition that caused the
reset persists (i.e., high temperature, RESET input low
or UVLO conditions), the MAX5935 will not acknowl-
edge any addressing from the serial interface.
After power-up (V
thresholds)
Hardware reset. The RESET input is driven low and
up high again any time after power-up.
Software reset. Writing a 1 into R1Ah[4] any time
after power-up.
Thermal shutdown
______________________________________________________________________________________
EE
2
and V
C-compatible interface. The
DD
rise above their UVLO
Quad Network Power Controller
Reset
Set high anytime during normal operation to turn off
power and clear the events and status registers of the
corresponding port. Port reset only resets the events
and status registers.
The MAX5935 contains four independent but identical
state machines to provide reliable and real-time control
of the four network ports. Each state machine has four
different operating modes: auto, semi-auto, manual,
and shutdown. Auto mode allows the device to operate
automatically without any software supervision. Semi-
auto mode, upon request, continuously detects and
classifies a device connected to a port but does not
power up that port until instructed by software. Manual
mode allows total software control of the device and is
useful in system diagnostic. Shutdown mode terminates
all activities and securely turns off power to the ports.
Switching between AUTO, SEMI, or MANUAL mode
does not take effect until the part finishes its current
task. When the port is set into SHUTDOWN mode, all
the port operations are immediately stopped and the
port remains idle until SHUTDOWN is exited.
Enter automatic (AUTO) mode by forcing the AUTO
input high prior to a reset, or by setting R12h[P_
M1,P_M0] to [1,1] during normal operation (see Tables
15 and 15a). In AUTO mode, the MAX5935 performs
detection and classification, and powers up the port
automatically once a valid power device (PD) is detect-
ed at the port. If a valid PD is not connected at the port,
the MAX5935 repeats the detection routine continuous-
ly until a valid PD is connected.
Going into AUTO mode, the DET_EN and CLASS_EN
bits are set to high and stay high unless changed by
software. Using software to set DET_EN and/or
CLASS_EN low causes the MAX5935 to skip detection
and/or classification. As a protection, disabling the
Detection routine in AUTO mode will not allow the cor-
responding port to power up, unless the DET_BYP
(R23H[4]) is set to 1.
The AUTO status is latched into the register only during
a reset. Any changes to the AUTO input after reset is
ignored.
Enter semi-automatic (SEMI) mode by setting
R12h[P_M1,P_M0] to [1,0] during normal operation
(see Tables 15 and 15a). In SEMI mode, the MAX5935,
upon request, performs detection and/or classification
repeatedly but does not power up the port(s), regard-
less of the status of the port connection.
for Power-Over-LAN
Semi-Automatic (SEMI) Mode
Port Reset (R1Ah[3:0])
Automatic (AUTO) Mode
Operation Modes
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