Features: IEEE 802.3af Compliant
Pin and Function Compatible with LTC4259A
Controls Four Independent, -48V-Powered Ethernet Ports in Either Endpoint or Midspan PSE Applications
Wide Digital Power Input, VDIG, Common-Mode Range: VEE to (AGND + 7.7V)
PD Violation of Class Current Protection
PD Detection and Classification
Provides Both DC and AC Load Removal Detections
I2C-Compatible, 3-Wire Serial Interface
Fully Programmable and Configurable Operation Through I2C Interface
Current Foldback and Duty-Cycle- Controlled/Programmable Current Limit
Short-Circuit Protection with Fast Gate Pulldown
Direct Fast Shutdown Control Capability
Programmable Direct Interrupt Output
Watchdog Mode Enable Hardware Graceful Takeover
ApplicationPower-Sourcing Equipment (PSE)
Power-Over-LAN/Power-Over-Ethernet
Switches/Routers
Midspan Power InjectorsPinout
Specifications(Voltages referenced to VEE, unless otherwise noted.)
AGND, DGND, DET_, VDD,RESET, A3, A2, A1, A0,SHD_,
OSC_IN, SCL, SDAIN, OUT_ and AUTO.....................-0.3V to +80V
GATE_ (internally clamped, Note 1)......................-0.3V to +11.4V
SENSE_ ..................................................................-0.3V to +24V
VDD, RESET, A3, A2, A1, A0, SHD_, OSC_IN, SCL, SDAIN and
AUTO to DGND .........................................................-0.3V to +7V
INT and SDAOUT to DGND......................................-0.3V to +12V
Maximum Current into INT, SDAOUT, DET_..........................80mA
Maximum Power Dissipation
36-Pin SSOP (derate 11.4mW/°C above +70°C) .........941mW
Operating Temperature Ranges:
MAX5945EAX ..................................................-40°C to +85°C
MAX5945CAX .....................................................0°C to +70°C
Storage Temperature Range ........................-65°C to +150°C
Junction Temperature...................................................+150°C
Lead Temperature (soldering, 10s) .............................+300°CDescriptionThe MAX5945 quad network power controller is designed for use in IEEE 802.3af-compliant power-sourcing equipment (PSE). The device provides power devices (PD) discovery, classification, current-limit, and both DC and AC load disconnect detections. The MAX5945 can be used in either endpoint PSE (LAN switches/routers) or midspan PSE (power injector) applications. The MAX5945 is pin and function compatible with LTC4259A.
The MAX5945 can operate autonomously or be controlled by software through an I2C*-compatible interface. Separate input and output data lines (SDAIN and SDAOUT) allow usage with optocouplers. The MAX5945 is a slave device. Its four address inputs allow 16 unique MAX5945 addresses. A separate INT output and four independent shutdown inputs (SHD_) allow fast response from a fault to port shutdown. A RESET input allows hardware reset of the device. A special watchdog feature allows the hardware to gracefully take over control if the software crashes. A cadence timing feature allows the MAX5945 to be used in midspan systems.
The MAX5945 is fully software configurable and programmable. A class-overcurrent detection function enables system power management to detect if a PD draws more current than the allowable amount for its class. Other features are input under/overvoltage lockout, overtemperature protection, output-voltage slew-rate limit during startup, power-good, and fault status. The MAX5945's programmability includes gate-charging current, currentlimit threshold, tartup timeout, overcurrent timeout, autorestart duty cycle, PD disconnect AC detection threshold, and PD disconnect detection timeout.
The MAX5945 is available in a 36-pin SSOP package and is rated for both extended (-40°C to +85°C) and commercial (0°C to +70°C) temperature ranges.
MAX5945 Data Sheet
