MAX5922AEUI+T ,+48V, Single-Port Network Power Switch For Power-Over-LANELECTRICAL CHARACTERISTICS(V = 48V, V = 3.3V, AGND_S = AGND = DGND = 0V, R = 0.5Ω ±1%, UVLO = open, ..
MAX5922BEUI ,+48V, Single-Port Network Power Switch For Power-Over-LANELECTRICAL CHARACTERISTICS(V = 48V, V = 3.3V, AGND_S = AGND = DGND = 0V, R = 0.5Ω ±1%, UVLO = open, ..
MAX5922CEUI ,+48V, Single-Port Network Power Switch For Power-Over-LANapplications and is fully compliant to the IEEE Power Device (PD) Detection and Classification802. ..
MAX5922CEUI+ ,+48V, Single-Port Network Power Switch For Power-Over-LANFeaturesThe MAX5922A/B/C is a single-port network power con-♦ IEEE 802.3af Complianttroller with an ..
MAX5924AEUB+ ,1V to 13.2V, n-Channel Hot-Swap Controllers Require No Sense ResistorFeaturesThe MAX5924/MAX5925/MAX5926 1V to 13.2V hot-swap ● Hot Swap 1V to 13.2V with V ≥ 2.25VCCcon ..
MAX5924AEUB+ ,1V to 13.2V, n-Channel Hot-Swap Controllers Require No Sense ResistorElectrical Characteristics(V , EN (MAX5924/MAX5925), EN1 (MAX5926) = +2.7V to +13.2V; EN2 (MAX5926) ..
MAZ8100-H ,Silicon planar typeZener DiodesMAZ8000 SeriesSilicon planar typeUnit : mmFor stabilization of power supplyKA
MAZ8100-L ,Silicon planar typeElectrical characteristics within part numbers T = 25°CaTemperaturecoefficient ofZener voltage Rev ..
MAZ8100M ,Silicon planar typeAbsolute Maximum Ratings T = 25°CaMarking SymbolParameter Symbol Rating UnitRefer to the list of t ..
MAZ8100-M ,Silicon planar typeElectrical Characteristics T = 25°CaParameter Symbol Conditions Min Typ Max UnitForward voltage V ..
MAZ8100-M ,Silicon planar typeelectrical characteristicsZ Zwithin part numbersReverse current I V ··············· Specified value ..
MAZ8110G ,Silicon planar typeElectrical Characteristics within Part Numbers T = 25°C±3°CaTemperatureZener Zener riseReversecoef ..
MAX5922AEUI+-MAX5922AEUI+T-MAX5922CEUI+
+48V, Single-Port Network Power Switch For Power-Over-LAN
General DescriptionThe MAX5922A/B/C is a single-port network power con-
troller with an integrated power MOSFET, operating from
a +32V to +60V supply rail. The device is specifically
designed for power-sourcing equipment (PSE) in power-
over-LAN applications and is fully compliant to the IEEE
802.3af standard. The MAX5922 provides power devices
(PD) discovery, classification, current limit, and other nec-
essary functions for an IEEE 802.3af compliant PSE.
The MAX5922 is suitable for PSE function in both
switch/router systems where the power is delivered to the
load through the signal pairs, and in midspan systems
where the power is delivered to the load through the
spare pairs. In midspan mode, a detection collision
avoidance circuit (MAX5922A/C only) provides the nec-
essary back-off timing to prevent fault detections that
happen when two different PSEs try to detect and
power the same PD. The MAX5922B/C have a detec-
tion disable input that can be connected high to disable
the detection/classification functions or connected low
to enable them.
The MAX5922 features a programmable undervoltage
lockout (UVLO) that keeps the device in shutdown until
the input voltage exceeds a certain threshold, set to 38V
(MAX5922A) or 28V (MAX5922B/C) internally. After suc-
cessfully discovering and classifying a PD, the MAX5922
enters startup mode. During startup, the MAX5922 limits
the output voltage and current slew rate to minimize EMI
(electromagnetic interference). The MAX5922 has an inte-
grated 0.45ΩN-channel power MOSFET that provides
efficient operation and simplified system design. The
MAX5922 monitors and provides current-limit protection
to the load at all times. The current limit is programmable
using an external current-sensing resistor. The MAX5922
features current-limit foldback and duty-cycle limit to
ensure robust operation during load-fault and short-circuit
conditions. Fault management allows the part to either
latch-off or autorestart after a fault.
The MAX5922 provides POK, ZC,and FAULTstatus sig-
nals to indicate output power is good, zero-current fault,
and other faults (overcurrent, overtemperature), respec-
tively. The MAX5922 is available in a 28-pin TSSOP pack-
age and is rated over the extended -40°C to +85°C
temperature range.
FeaturesIEEE 802.3af Compliant+32V to +60V Wide Operating Input Range 0.45ΩIntegrated Power SwitchPower Device (PD) Detection and Classification100µA PD Leakage Detection TolerantProgrammable Current LimitZero-Current Detection with Status OutputDetection Collision Avoidance Option for Midspan
ApplicationInput Logic Signals Compatible with 1.8V to 5V
CMOS LogicSeparate Analog and Digital Grounds with Up to
±4V OffsetPower-Good Status OutputOvercurrent and Overtemperature Protection with
Status OutputsCurrent-Limit Foldback with Timeout and Duty-
Cycle ControlLatch or Autorestart Fault Management
Applications
MAX5922
+48V, Single-Port Network Power Switch
For Power-Over-LAN19-2708; Rev 0; 4/03
PARTTEMP RANGEPIN-PACKAGEMAX5922AEUI-40°C to +85°C28 TSSOP
MAX5922BEUI-40°C to +85°C28 TSSOP
MAX5922CEUI-40°C to +85°C28 TSSOP
Ordering Information
Typical Application Circuits, Selector Guide, and Pin
Configuration appear at end of data sheet.Power-Sourcing Equipment (PSE)
Power-Over-LAN/Power-Over-MDI
(Media-Dependent Interface)
Computer Telephony
Single-Port Power Injector/Adapter
Midspan Power Injector
Switches/Routers with In-Line Power
MAX5922
+48V, Single-Port Network Power Switch
For Power-Over-LAN
ABSOLUTE MAXIMUM RATINGSStresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
(All voltages with respect to AGND_S, unless otherwise noted.)
IN............................................................................-0.3V to +76V
UVLO........................................................................-0.3V to +6V
VDIGto DGND..........................................................-0.3V to +6V
OUT.......................................................-0.3V to (VDRAIN+ 0.3V)
DRAIN..........................................................-0.3V to (VIN+ 0.3V)
RDT.........................................................................-0.3V to +12V
RCL to IN................................................................-10V to +0.3V
EN, DET_DIS, DCA, CLASS, ZC_EN,
and LATCH to DGND...........................................-0.3V to +6V
POK, ZC, CL0, CL1, CL2, and FAULTto DGND......-0.3V to +6V
DGND..........................................................................-5V to +5V
Maximum Current into Drain.................................................0.8A
Maximum Current into POK, ZC, CL0, CL1, CL2, FAULT...20mA
Continuous Power Dissipation (TA= +70°C)
28-Pin TSSOP (Derate 12.8mW/°C above +70°C).....1026mW
Operating Temperature Range...........................-40°C to +85°C
Junction Temperature......................................................+150°C
Storage Temperature Range.............................-65°C to +160°C
Lead Temperature (soldering, 10s).................................+300°C
ELECTRICAL CHARACTERISTICS(VIN= 48V, VDIG= 3.3V, AGND_S = AGND = DGND = 0V, RSENSE= 0.5Ω±1%, UVLO = open, EN = VDIG, RRCL= 150Ω±1%, RRDT
= 18.2kΩ±1%, TA= -40°C to +85°C, unless otherwise noted. Typical values are at TA= +25°C.) (Note 1)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITSAnalog Input Voltage RangeVIN3260V
Analog Input Supply CurrentIINVIN = 60V, measured at AGND after OUT
has stopped slewing11.6mA
Digital Input Voltage RangeVDIG1.655.50V
Digital Input Supply CurrentIDIGVDIG = 5V0.050.1mA
DGND to AGND Operating
Voltage Range-4+4V
Current-Limit Response TimeOUT shorted to AGND (Note 2)1µs
OUT Current-Limit Foldback
VoltageVFBSTOP(Note 3)18V
Maximum voltage across RSENSE at VOUT >
VFBSTOP198212223Current-Limit Sense Voltage
(VIN - VDRS) (Note 4)VILIM
0°C to +70°C203212221
Current-Limit Sense Foldback
Voltage (VIN - VDRS)VILIM_fbVOUT = 0V647076mV
Overcurrent TimeouttOCOUT shorted to AGND (Note 5)506075ms
TA = +25°C0.45DMOS On-ResistanceRDSONIOUT = 100mATA = +85°C0.75Ω
Power-Off OUT Sink CurrentEN = DGND, VOUT = 48V15µA
Maximum Output Voltage Slew
RatedVOUT/dtVOUT rising, no load100V/ms
Maximum Output Current Slew
RatedIOUT/dtVOUT rising, CLOAD = 100µF35A/ms
VOUT rising, POK from low to high650750850mVPower-OK Threshold (VIN - VOUT)VTHPOKHysteresis10%
POK Output Low VoltageVPOK_LOWIPOK = 3mA0.4V
POK Output Leakage CurrentVPOK = 3.3V0.051µA
MAX5922
+48V, Single-Port Network Power Switch
For Power-Over-LAN
ELECTRICAL CHARACTERISTICS (continued)(VIN= 48V, VDIG= 3.3V, AGND_S = AGND = DGND = 0V, RSENSE= 0.5Ω±1%, UVLO = open, EN = VDIG, RRCL= 150Ω±1%, RRDT
= 18.2kΩ±1%, TA= -40°C to +85°C, unless otherwise noted. Typical values are at TA= +25°C.) (Note 1)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITStPOK_LOWPOK from high to low, VOUT falling1.01.41.8POK Output Delay (Note 6)tPOK_HIGHPOK from low to high, VOUT rising7488102ms
Zero-Current Detection Threshold
Voltage (VIN - VDRS)VZCTH(Note 4)2.73.754.8mV
ZC Output Low VoltageV ZC_LOWI ZC = 3mA0.4V
ZC Output Leakage CurrentV ZC = 3.3V0.051µA
Zero-Current Detection DelaytZCDELZC from high to low, IOUT falling (Note 7)300350400ms
Zero-Current Deglitch TimetZC_DEGIOUT rising10ms
Temperature rising150°CThermal ShutdownHysteresis30°C
Shutdown Autorestart TimetRESTARTLATCH = low (Note 8)1.601.922.24s
UNDERVOLTAGE LOCKOUTMAX5922A363840
UVLO floating, VIN risingMAX5922B/
MAX5922C262830
MAX5922A4.4
Default VIN UVLOUVLOTH
HysteresisMAX5922B/C2.5
MAX5922A1.361.381.41
Referenced to AGND_S,
VUVLO risingMAX5922B/
MAX5922C1.311.331.36V
MAX5922A160UVLO Comparator ThresholdVREF
HysteresisMAX5922B/
MAX5922C120mV
UVLO Input Resistance50kΩ
LOGIC SIGNALSEN, LATCH, DCA, DET_DIS
CLASS, and ZC_EN Input High
Voltage
VIH1.65V < VDIG < 5.5V0.7 ×
VDIGV
1.65V < VDIG < 2.0V0.3 ×
VDIG
EN, LATCH, DCA, DET_DIS
CLASS, and ZC_EN Input Low
Voltage
VIL
2.0V < VDIG < 5.5V0.8
EN, LATCH, DCA, DET_DIS
CLASS, and ZC_EN Input Current-1+1µA
EN Low Pulse Width3µs
FAULT, CL0, CL1 and CL2,
Output Low VoltageVOLISINK = 3mA0.4V
FAULT, CL0, CL1 and CL2,
Output Leakage Current
VFAULT = VCL0 = VCL1 = VCL2 = 3.3V,
CLASS = 0V0.051µA
MAX5922
+48V, Single-Port Network Power Switch
For Power-Over-LAN
ELECTRICAL CHARACTERISTICS (continued)(VIN= 48V, VDIG= 3.3V, AGND_S = AGND = DGND = 0V, RSENSE= 0.5Ω±1%, UVLO = open, EN = VDIG, RRCL= 150Ω±1%, RRDT
= 18.2kΩ±1%, TA= -40°C to +85°C, unless otherwise noted. Typical values are at TA= +25°C.) (Note 1)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITS
PD DETECTION (See Figure 3, PD Detection Section)Detection Probe Voltage Phase IVPBIRPD = 19kΩ to 26.5kΩ3.644.4V
Detection Probe Voltage Phase IIVPBIIRPD = 19kΩ to 26.5kΩ7.288.8V
Detection Short-Circuit CurrentISC_DETOUT shorted to AGND0.681.50mA
Valid PD Detected Lower-Limit
ThresholdRPDL(Note 9)1519kΩ
Valid PD Detected Upper-Limit
ThresholdRPDH(Note 9)26.533.0kΩ
Total Detection Timetdet170196ms
Reject Capacitance During
DetectionCPDHRPD = 19kΩ to 26.5kΩ6µF
Allowable Capacitance During
DetectionCPDLRPD = 19kΩ to 26.5kΩ0.6µF
PD CLASSIFICATION (See PD Classification Mode Section)IOUT = 0.5mA to 45mA1520Classification Probe VoltageVCLASSNo load28V
Classification Short-Circuit
CurrentISC_CLASSShorted to AGND4865mA
Classification Time DurationtCLASSFrom detection completion1521.326ms
Total Detection and Classification
Delay TimetTOTFrom channel-enabled to power delivered
at the OUT pin191230ms
Class 0 to Class 1 ThresholdICLASS_1L5.56.57.5mA
Class 1 to Class 2 ThresholdICLASS_1-21314.516mA
Class 2 to Class 3 ThresholdICLASS_2-3212325mA
Class 3 to Class 4 ThresholdICLASS_3-4313335mA
Default To Class 0 High-Current
Lower-Limit ThresholdICLASS_4-04346.5mA
Collision Detection Delay Time
(MAX5922A/MAX5922C Only)tDCADCA = high, RPD = 15kΩ2.382.83.22s
Note 1:All specifications are 100% production tested at TA= +25°C, unless otherwise noted. All temperature limits are guaranteed by
design.
Note 2:This is the time from an output overcurrent or short-circuit condition until the output goes into regulated current limit.
Note 3:OUT voltage above which the output current limit is at its full value (see Figure 8).
Note 4:To be consistent with the IEEE 802.3af standard, choose RSENSE= 0.5Ω±1%.
Note 5:This is the time the part stays in current-limit mode during overload condition. After tOC elapses (or when the junction temperature
hits +150°C) the part shuts down.
Note 6:See the Typical Operating Characteristicsand Figure 6.
Note 7:This is the delay from IOUTfalling below the zero-current threshold until ZCgoes low and the IC shuts down (see the Zero-Current
Detectionsection).
Note 8:See the Fault Managementsection.
Note 9:PD is detected by the procedures specified by the IEEE 802.3af standard. A probe voltage VPBI(+4V typically) is forced at OUT
and the current IS1is measured after tDET/2. A second probe voltage VPBII(+8V typically) is then forced and IS2 measured after
tDET / 2 again. The voltage increment is then divided by the difference of the two currents (IS2- IS1). This is the PD resistance value.
MAX5922
+48V, Single-Port Network Power Switch
For Power-Over-LAN
VIN SUPPLY CURRENT
vs. INPUT VOLTAGEMAX5922 toc01
INPUT VOLTAGE (V)
SUPPLY CURRENT (mA)5752474237
TA = +85°C
TA = +25°C
TA = -40°C
MEASURED AT AGND
VIN SUPPLY CURRENT
vs. TEMPERATUREMAX5922 toc02
TEMPERATURE (°C)
SUPPLY CURRENT (mA)5035205-10-25
VIN = 60V
VIN = 48V
VIN = 32V
MEASURED AT
AGND
IDIG
DIGITAL SUPPLY CURRENT
vs. TEMPERATURE
MAX5922 toc03
TEMPERATURE (°C)5035205-10-25-4080
DEFAULT V
UVLO (V)
VIN UNDERVOLTAGE LOCKOUT
vs. TEMPERATURE
MAX5922 toc04
TEMPERATURE (°C)5035205-10-25-4080
VIN RISING
VIN FALLING
ON-RESISTANCE (
MOSFET RDSON
vs. TEMPERATURE
MAX5922 toc05
TEMPERATURE (°C)5035205-10-25-4080
IOUT = 100mA
SENSE TRIP VOLTAGE
vs. TEMPERATUREMAX5922 toc06
TEMPERATURE (°C)
SENSE TRIP VOLTAGE (V)653550-10520-25
VIN = 60VVIN = 48V
VIN = 32V
FOLDBACK-CURRENT LIMIT
(ILIM vs. VOUT)MAX5922 toc07
OUTPUT VOLTAGE (V)
ILIM (A)403035101520255
ZERO-CURRENT THRESHOLD VOLTAGE (mV)3.52
ZERO-CURRENT DETECTION THRESHOLD
VOLTAGE vs. TEMPERATURE
MAX5922 toc08
TEMPERATURE (°C)5035205-10-25-4080
VIN = 60V
VIN = 32V
VIN = 48V
ON-RESISTANCE vs. VDRAINMAX5922 toc09
INPUT VOLTAGE (V)
ON-RESISTANCE (524844403632
IOUT = 100mA
TA = +85°C
TA = +25°C
TA = -40°C
Typical Operating Characteristics(MAX5922A, VIN= 48V, VDIG, EN, LATCH, CLASS, and ZC_EN = 3.3V, DCA, AGND_S = AGND = DGND = 0V, RSENSE= 0.5Ω±1%,
UVLO floating, RRCL= 150kΩ, RRDT= 18.2kΩ, TA= +25°C, unless otherwise noted.)
MAX5922
+48V, Single-Port Network Power Switch
For Power-Over-LAN
Typical Operating Characteristics (continued)(MAX5922A, VIN= 48V, VDIG, EN, LATCH, CLASS, and ZC_EN = 3.3V, DCA, AGND_S = AGND = DGND = 0V, RSENSE= 0.5Ω±1%,
UVLO floating, RRCL= 150kΩ, RRDT= 18.2kΩ, TA= +25°C, unless otherwise noted.)
DIGITAL SUPPLY CURRENT vs. VDIGVDIG (V)
IDIG
MAX5922toc10
OVERCURRENT TIMEOUT
(RLOAD FROM 240Ω TO 75Ω)
MAX5922 toc11
20ms/div
5V/div
200mA/div
5V/div
VOUT
POK
IOUT
20V/div
FAULT
SHORT-CIRCUIT RESPONSE TIMEMAX5922 toc12
20ms/div
5V/div
200mA/div5V/div
VOUT
POK
IOUT
20V/div
FAULT
POK LOW-TO-HIGH DELAY TIMEMAX5922 toc13
100ms/div
20V/div
5V/div
VOUT
POK
POK HIGH-TO-LOW DELAY TIMEMAX5922 toc14
1ms/div
20V/div
5V/div
VOUT
POK
ZC TO OUT DELAYMAX5922 toc15
400μs/div
20V/div5V/div5V/div
1.25mA/div
VOUT
POK
IOUT
MAX5922
+48V, Single-Port Network Power Switch
For Power-Over-LAN
OVERCURRENT RESTART DELAYMAX5922 toc19
400ms/div
20V/div
5V/div
500mA/div
5V/div
VOUT
POK
IOUT
FAULT
tRESTART
STARTUP WITH VALID
PD (25kΩ AND 0.1μF)MAX5922 toc20
40ms/div
20V/div
5V/div
5V/div
200mA/div
VOUT
POK
IOUT
STARTUP WITH INVALID
PD (25kΩ AND 10μF)MAX5922 toc21
100ms/div
5V/div
250μA/div
2V/div
VOUT
POK
IOUT
Typical Operating Characteristics (continued)(MAX5922A, VIN= 48V, VDIG, EN, LATCH, CLASS, and ZC_EN = 3.3V, DCA, AGND_S = AGND = DGND = 0V, RSENSE= 0.5Ω±1%,
UVLO floating, RRCL= 150kΩ, RRDT= 18.2kΩ, TA= +25°C, unless otherwise noted.)
ZERO-CURRENT HIGH-TO-LOW
DETECTION TIMEMAX5922 toc16
100ms/div
20V/div
5V/div
5V/div
1.25mA/div
VOUT
POK
IOUT
tZCDEL
ZERO-CURRENT (IIms GLITCH)
DEGLITCH TIMEMAX5922 toc17
100ms/div
20V/div
5V/div
5V/div
200mA/div
VOUT
POK
IOUTtZCDEL
GLITCH > tZC_DEG
ZERO-CURRENT
DEGLITCH TIME (10ms GLITCH)MAX5922 toc18
100ms/div
20V/div
5V/div
5V/div
200mA/div
VOUT
POK
IOUT
tZCDEL
GLITCH > tZC_DEG
MAX5922
+48V, Single-Port Network Power Switch
For Power-Over-LAN
STARTUP WITH INVALID
PD (15kΩ)MAX5922 toc22
100ms/div
5V/div
250μA/div
2V/div
VOUT
POK
STARTUP WITH INVALID
PD (33kΩ)MAX5922 toc23
40ms/div
5V/div
250μA/div
2V/div
VOUT
IOUT
POK
STARTUP WITH OUTPUT
SHORTED TO AGNDMAX5922 toc24
100ms/div
5V/div
5V/div
500μA/div
2V/div
VOUT
IOUT
POK
STARTUP WITH MIDSPAN MODE
(DCA = VDIG, VALID PD (25kΩ AND 0.1μF))MAX5922 toc25
100ms/div
5V/div
5V/div
500μA/div
20V/divVOUT
IOUT
POK
STARTUP WITH MIDSPAN MODE
(DCA = VDIG, INVALID PD (15kΩ))MAX5922 toc26
400ms/div
5V/div
250μA/div
2V/div
VOUT
IOUT
POK
STARTUP WITH MIDSPAN MODE
(DCA = VDIG, INVALID PD (33kΩ))MAX5922 toc27
400ms/div
5V/div
250μA/div
2V/div
VOUT
IOUT
POK
Typical Operating Characteristics (continued)(MAX5922A, VIN= 48V, VDIG, EN, LATCH, CLASS, and ZC_EN = 3.3V, DCA, AGND_S = AGND = DGND = 0V, RSENSE= 0.5Ω±1%,
UVLO floating, RRCL= 150kΩ, RRDT= 18.2kΩ, TA= +25°C, unless otherwise noted.)
MAX5922
+48V, Single-Port Network Power Switch
For Power-Over-LAN
STARTUP WITH VALID PD
(25kΩ, ZC_EN = LOW)MAX5922 toc28
100ms/div
5V/div
20V/div
1.25mA/div
VOUT
IOUT
POK
STARTUP WITH
DIFFERENT PD CLASSESMAX5922 toc29
40ms/div
5V/div
5V/div
20mA/div
VOUT
IOUT
POK
SHORT TO AGND
CLASS 4
CLASS 3
CLASS 2CLASS 1
CLASS 0
OVERCURRENT TIMEOUT
(RLOAD FROM 240Ω to 75Ω)MAX5922 toc30
2ms/div
5V/div
20V/div
200mA/div
VOUT
IOUT
POK
OUTPUT SHORT-CIRCUIT RESPONSEMAX5922 toc31
200μs/div
200mA/div
20V/div
VOUT
IOUT
Typical Operating Characteristics (continued)(MAX5922A, VIN= 48V, VDIG, EN, LATCH, CLASS, and ZC_EN = 3.3V, DCA, AGND_S = AGND = DGND = 0V, RSENSE= 0.5Ω±1%,
UVLO floating, RRCL= 150kΩ, RRDT= 18.2kΩ, TA= +25°C, unless otherwise noted.)
OUTPUT SHORT-CIRCUIT RESPONSEMAX5922 toc32
4μs/div
10A/div
20V/div
VOUT
IOUT
MAX5922
+48V, Single-Port Network Power Switch
For Power-Over-LAN
PINNAMEFUNCTION*AGNDAnalog Ground. This is the return of analog power input. AGND can vary ±4V from DGND. AGND and
DGND must be connected together at a single point in the system.
1, 2DRAIN
Drain connection for the integrated MOSFET. Connect a sense resistor, RSENSE, from DRAIN to IN.
These pins are also the current-sense resistor negative terminal. RSENSE sets the overcurrent-limit
and open-circuit detection threshold. These two pins must be connected together.
3, 6, 26N.C.No Connection. Not internally connected. Leave pins 6 and 26 open. Pins 6 and 26 are left
unconnected to provide additional spacing between the high-voltage pins and other pins.
4IN
Input Voltage. Connect to a positive voltage source between +32V to +60V from IN to AGND. This is
the current-sense resistor positive terminal. Bypass to AGND with a 47µF, 100V electrolytic capacitor
and a 0.1µF, 100V ceramic capacitor. Place the ceramic capacitor close to this pin.RCLClassification Sense Resistor. Connect a 150Ω ±1% resistor from RCL to IN for sensing the
classification current. Leave RCL floating when the PD classification function is not used.AGND_SAnalog Ground Sense. Connect a 1Ω resistor from AGND_S to AGND. This resistor protects the IC
during an output short-circuit condition.UVLOUndervoltage Lockout Adjustment Input. Referenced to AGND. Connect to the center point of a
resistive-divider from IN to AGND to adjust the UVLO threshold. Leave open for default value.RDT
Detection Sense Resistor. Connect an 18.2kΩ ±1% resistor from RDT to AGND for sensing the PD
detection current. Add a 680nF capacitor in parallel to this resistor to filter out the power-line noise.
Connect RDT to AGND when the PD detection function is not used.FAULT
Fault Signal Open-Drain Logic Output. Reference to DGND. FAULT is latched low when:An overtemperature condition occurs and/or,An overcurrent condition that has lasted for more than tOC.POK
Power-OK, Open-Drain Logic Output. Reference to DGND. POK goes open drain a time tPOK_HIGH
after VOUT raises to within VTHPOK from VIN. POK goes low a time tPOK_LOW after VOUT falls out of the
VTHPOK from VIN.ZC
Zero-Current Fault Signal. Open-drain logic output. Reference to DGND. ZC is latched low when there
is a zero-current condition lasting longer than tZCDEL. ZC is open-drain otherwise. The zero-current
detection circuit is enabled immediately after the POK signal goes high. The ZC is unlatched after a
valid PD has been detected and eventually classified.TP1Must be Left Open or Connected to AGNDTP2Must be Left Open or Connected to AGNDTP3Must be Left Open or Connected to AGNDCL2Classification Report Logic Output Bit 2. See the PD Classification section (Table 2).CL1Classification Report Logic Output Bit 1. See the PD Classification section (Table 2).CL0Classification Report Logic Output Bit 0. See the PD Classification section (Table 2).DGNDDigital Ground. DGND can vary ±4V from AGND. DGND and AGND must to be connected together at
a single point in the system.LATCH
Fault Management Selection Digital Input. Referenced to DGND. Connect to a logic high to latch off
after a fault condition. Connect to a logic low for automatic restart after a fault condition (see the Fault
Management section).
Pin Description*This is not a device pin.
MAX5922
+48V, Single-Port Network Power Switch
For Power-Over-LAN
PINNAMEFUNCTIONZC_ENZero-Current-Detection Enable Logic Input. Referenced to DGND. Connect ZC_EN to a logic high to
enable the zero-current detection circuitry. Connect ZC_EN to a logic low to disable this function.ENON/OFF Control-Logic Input. Referenced to DGND. Connect to a logic high to enable the device.
Connect to a logic low to disable the device and reset a latched-off condition.VDIG
Digital Supply Voltage. VDIG is the supply voltage for the internal digital logic circuity. EN, LATCH,
CLASS, DET_DIS, DCA, and ZC_EN input logic thresholds are automatically scaled to the voltage on
VDIG. See the Typical Application Circuit for proper filtering.CLASSClassification Enable Digital Input. Connect to DGND to disable the classification function. Connect to
VDIG to enable the classification function.
DET_DIS
PD Detection Disable Logic Input. When DET_DIS is connected to a logic high, the part skips the
detection and classification (regardless of the status of CLASS) phases and powers on immediately
after EN = high (MAX5922B/MAX5922C only).
DCA
Detection Collision Avoidance Logic Input. Connect to a logic high to activate the detection collision
avoidance circuitry for midspan system. Connect to DGND to disable this function. (MAX5922A only).
See the Detection Collision Avoidance section.
27, 28OUTOutput Voltage
Pin Description (continued)CLASS
POK
VDIG
LATCH
ZC_EN
DCA
CL2
CL1
CL0
DGND
FAULT
LOGIC-
LEVEL
TRANSLATOR
LOGIC
CONTROL
ANALOG
CONTROL
VOLTAGE
REGULATOR
OSC
DETECTION
AND
CLASSIFICATION
CIRCUITRY
CHARGE
PUMP
CSP
DRAIN
OUT
UVLO
RCL
RDT
AGND
MAX5922
Figure 1. MAX5922 Block Diagram
