General DescriptionThe MAX5945 quad network power controller is designedfor use in IEEE 802.3af-compliant power-sourcing equip-ment (PSE). The device
MAX5945Quad Network Power Controllerfor Power-Over-LAN10 ______________________________________________________________________________________DETECTI
MAX5945Quad Network Power Controllerfor Power-Over-LAN______________________________________________________________________________________ 11PIN NAM
MAX5945Detailed DescriptionThe MAX5945 four-port network power controller con-trols -32V to -60V negative supply rail systems. Use theMAX5945, which i
agement where it detects a PD that draws more currentthan the allowable amount for its class. The MAX5945’sextensive programmability enhances system f
MAX5945Setting R19h[PWR_ON_] (Table 21) high immediatelyterminates detection/classification routines and turns onpower to the port(s).R14h[DET_EN_, CL
Table 2 shows the IEEE 802.3af requirement for a PSEclassifying a PD at the power interface (PI).Powered StateWhen the part enters PWR MODE, the tSTAR
MAX5945Overcurrent ProtectionA sense resistor (RS), connected between SENSE_ andVEE, monitors the load current. Under all circum-stances, the voltage
MOSFET Gate DriverConnect the gate of the external n-channel MOSFET toGATE_. An internal 50µA current source pulls GATE_ to(VEE+ 10V) to turn on the M
MAX5945The MAX5945 also features three other undervoltageand overvoltage interrupts: VEEundervoltage interrupt(VEEUV), VDDundervoltage interrupt (VDDU
Start and Stop ConditionsBoth SCL and SDA remain high when the interface isnot busy. A master signals the beginning of a transmis-sion with a START (S
MAX5945Quad Network Power Controllerfor Power-Over-LAN2 _______________________________________________________________________________________ABSOLUT
MAX5945Bit TransferEach clock pulse transfers one data bit (Figure 8). Thedata on SDA must remain stable while SCL is high.AcknowledgeThe acknowledge
Message Format for Writing the MAX5945A write to the MAX5945 comprises of the MAX5945’sslave address transmission with the R/W bit set to 0, fol-lowed
MAX5945Message Format for ReadingThe MAX5945 reads using the MAX5945’s internallystored command byte as an address pointer, the sameway the stored com
MAX5945Quad Network Power Controllerfor Power-Over-LAN______________________________________________________________________________________ 23ADDRESS
MAX5945Quad Network Power Controllerfor Power-Over-LAN24 ______________________________________________________________________________________ADDRESS
If the port remains in current limit or the PGOOD condi-tion is not met at the end of the startup period, the portshuts down and the corresponding STR
MAX5945function. OSC_FAIL generates an interrupt only if atleast one of the ACD_EN (R13h[7:4]) bits is set high.A thermal-shutdown circuit monitors th
Software resets of ports (RESET_P_ bit, Table 22) donot affect the mode register.Setting DCD_EN_ to 1 enables the DC load disconnectdetection feature
MAX5945In MANUAL mode, R14h works like a pushbutton. Setthe bits high to begin the corresponding routine. The bitclears after the routine finishes.Whe
ther extend the programming range of these timers andalso increase the programming resolution.When the MAX5945 shuts down a port due to anextended ove
MAX5945Quad Network Power Controllerfor Power-Over-LAN_______________________________________________________________________________________ 3ELECTRI
MAX5945when the port is already powered and during shut-down. PWR_OFF_ is ignored when the port is alreadyoff and during shutdown. After execution, th
Writing a 1 to CLR_INT (Table 22) clears all the eventregisters and the corresponding interrupt bits in registerR00h. Writing a 1 to RESET_P_ turns of
MAX5945the bits in register R12h to 00. A high in HWMODE_switches the port into auto mode by setting the bits inregister R12h to 11. If WD_INT_EN is s
Use TF_PR[3:0] to set the nominal value for tDISCaccording to the following formula:tDISCnominal = 238ms + 16ms x Nwhere N is the decimal value of the
MAX5945Use the program registers (Table 29) to set the nominalvalue for tFAULTand tSTARTfor all ports according tothe following formula:tFAULTnominal
MAX5945Quad Network Power Controllerfor Power-Over-LAN______________________________________________________________________________________ 35Table 3
MAX5945Quad Network Power Controllerfor Power-Over-LAN36 ______________________________________________________________________________________Table 3
MAX5945Quad Network Power Controllerfor Power-Over-LAN______________________________________________________________________________________ 37Figure
MAX5945Quad Network Power Controllerfor Power-Over-LAN38 ______________________________________________________________________________________Figure
MAX5945Quad Network Power Controllerfor Power-Over-LAN______________________________________________________________________________________ 39Figure
MAX5945Quad Network Power Controllerfor Power-Over-LAN4 _______________________________________________________________________________________ELECTRI
MAX5945Quad Network Power Controllerfor Power-Over-LAN40 ______________________________________________________________________________________Figure
MAX5945Quad Network Power Controllerfor Power-Over-LAN______________________________________________________________________________________ 41DESIGNA
MAX5945Quad Network Power Controllerfor Power-Over-LAN42 ______________________________________________________________________________________MAX5945
MAX5945Quad Network Power Controllerfor Power-Over-LAN______________________________________________________________________________________ 43MAX5945
MAX5945Quad Network Power Controllerfor Power-Over-LANMaxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodi
MAX5945Quad Network Power Controllerfor Power-Over-LAN_______________________________________________________________________________________ 5ELECTRI
MAX5945Quad Network Power Controllerfor Power-Over-LAN6 _______________________________________________________________________________________Note 2:
MAX5945Quad Network Power Controllerfor Power-Over-LAN_______________________________________________________________________________________ 7DIGITAL
MAX5945Quad Network Power Controllerfor Power-Over-LAN8 _______________________________________________________________________________________OVERCUR
MAX5945Quad Network Power Controllerfor Power-Over-LAN_______________________________________________________________________________________ 9OVERCUR
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