MAX5942AESE-MAX5942BESE Fast Delivery |IC PHOENIX CO.,LIMITED

MAX5942AESE ,IEEE 802.3af power-over-ethernet interface/PWM controller for power deviceFeaturesThe MAX5942A/MAX5942B integrate a complete power Powered Device InterfaceIC for powered d ..
MAX5942BCSE ,IEEE 802.3af Power-Over-Ethernet Interface/PWM Controller for Power DevicesFeaturesThe MAX5942A/MAX5942B integrate a complete power Powered Device InterfaceIC for powered d ..
MAX5942BCSE+ ,IEEE 802.3af Power-Over-Ethernet Interface/PWM Controller for Power DevicesFeaturesThe MAX5942A/MAX5942B integrate a complete power ♦ Powered Device InterfaceIC for powered d ..
MAX5942BESE ,IEEE 802.3af power-over-ethernet interface/PWM controller for power deviceApplications MAX5942BCSE 0°C to +70°C 16 SO 50*Future product—contact factory for availability.I ..
MAX5943AEEE ,FireWire Current Limiter and Low-Drop ORing Switch ControllerApplicationsMAX5943BEEE -40°C to +85°C 16 QSOPFireWire Desktop/Notebook PortMAX5943CEEE -40°C to +8 ..
MAX5943AEEE+ ,FireWire Current Limiter and Low-Drop ORing Switch ControllerApplicationsMAX5943DEEE -40°C to +85°C 16 QSOPFireWire Desktop/Notebook PortMAX5943EEEE -40°C to +8 ..
MAZ8130-L ,Silicon planar typeElectrical Characteristics T = 25°CaParameter Symbol Conditions Min Typ Max UnitForward voltage V ..
MAZ8130-M ,Silicon planar typeElectrical characteristics within part numbers T = 25°CaTemperaturecoefficient ofZener voltage Rev ..
MAZ8150G ,Silicon planar typeFeatures Package Extremely low noise voltage caused from the diode (2.4 V to Code 39V, 1/3 to 1 ..
MAZ8150-H ,Silicon planar typeZener DiodesMAZ8000 SeriesSilicon planar typeUnit : mmFor stabilization of power supplyKA
MAZ8150-L ,Silicon planar typeFeatures•Extremely low noise voltage caused from the diode (2.4V to 39V,1/3 to 1/10 of our conventi ..
MAZ8150-M ,Silicon planar typeAbsolute Maximum Ratings T = 25°CaMarking SymbolParameter Symbol Rating UnitRefer to the list of t ..

MAX5942AESE-MAX5942BESE
IEEE 802.3af power-over-ethernet interface/PWM controller for power device
General Description
The MAX5942A/MAX5942B integrate a complete power
IC for powered devices (PD) in a power-over-ethernet
(PoE) system. The MAX5942A/MAX5942B provide a PD
interface and a compact DC-DC PWM controller suitable
for flyback and forward converters in either isolated or
nonisolated designs.
The MAX5942A/MAX5942B PD interface complies with
the IEEE 802.3af standard, providing the PD with a detec-
tion signature, a classification signature, and an integrat-
ed isolation switch with programmable inrush current
control. These devices also feature power-mode under-
voltage lockout (UVLO) with wide hysteresis and power-
good status outputs.
The MAX5942A/MAX5942B also integrate all the build-
ing blocks necessary for implementing DC-DC fixed-
frequency isolated power supplies. This device is a
current-mode controller with an integrated high startup
circuit suitable for isolated telecom/industrial voltage
range power supplies. A high-voltage startup circuit
allows the PWM controller to draw power directly from the
18V to 67V input supply during startup. The switching
frequency is internally trimmed to 275kHz ±10%, thus
reducing magnetics and filter components. The
MAX59412A allows an 85% operating duty cycle and can
be used to implement flyback converters. The MAX5942B
limits the operating duty cycle to less than 50% and can
be used in single-ended forward converters. The
MAX5942A/MAX5942B are designed to work with or with-
out an external diode bridge in front of the PD.
The MAX5942A/MAX5942B are available in 16-pin SO
packages.
ApplicationsPhones
Wireless Access Nodes
Internet Appliances
Computer Telephony
Security Cameras
Power Devices in Power-Over-Ethernet/
Power-Over-MDI
FeaturesPowered Device Interface
Fully Integrated IEEE 802.3af-Compliant PD
Interface
PD Detection and Programmable Classification
Signatures
Less than 10µA Leakage Current Offset During
Detection
Integrated MOSFET for Isolation and Inrush
Current Limiting
Gate Output Allows External Control of the
Internal Isolation FET
Programmable Inrush Current Control/ULVO
PGOOD/PGOODOutputs Enable PWM
ControllerPWM Controller
Wide Input Range: 18V to 67V
Isolated (Without Optocoupler) or Nonisolated
Power Supply
Current-Mode Control
Leading-Edge Blanking
Internally Trimmed 275kHz ±10% Oscillator
Soft-Start
MAX5942A/MAX5942B
IEEE 802.3af Power-Over-Ethernet
Interface/PWM Controller for Power Devices
Ordering Information
19-3024; Rev 0; 10/03
Typical Operating Circuit appears at end of data sheet.
*Future product—contact factory for availability.
Pin Configuration
MAX5942A/MAX5942B
IEEE 802.3af Power-Over-Ethernet
Interface/PWM Controller for Power Devices
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(VIN= (GND - VEE) = 48V, GATE = PGOOD= PGOOD = OPEN, V- tied to OUT, V+ tied to GND, UVLO = VEE, TA= TMINto TMAX,
Stresses 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 are referenced to VEE, unless otherwise noted.)
GND........................................................................-0.3V to +80V
OUT, PGOOD...........................................-0.3V to (GND + 0.3V)
RCL, GATE.............................................................-0.3V to +12V
UVLO........................................................................-0.3V to +8V
PGOOD to OUT.........................................-0.3V to (GND + 0.3V)
V+ to V-...................................................................-0.3V to +80V
VDDto V-.................................................................-0.3V to +40V
VCCto V-..............................................................-0.3V to +12.5V
FB, NDRV, SS_SHDN, CS to V-..................-0.3V to (VCC+ 0.3V)
Maximum Input/Output Current (continuous)
OUT to VEE...................................................................500mA
GND, RCL to VEE............................................................70mA
UVLO, PGOOD, PGOOD to VEE.....................................20mA
GATE to VEE....................................................................80mA
VDD, VCC.........................................................................20mA
NDRV Continuous...........................................................25mA
NDRV (pulsed for less than 1µs).......................................±1A
Continuous Power Dissipation (TA= +70°C)
16-Pin SO (derate 9.1mW/°C above +70°C)................727mW
Operating Temperature Ranges
MAX5942_CSE...................................................0°C to +70°C
MAX5942_ESE................................................-40°C to +85°C
Storage Temperature Range.............................-65°C to +150°C
Junction Temperature......................................................+150°C
Lead Temperature (soldering, 10s) ................................+300°C
MAX5942A/MAX5942B
IEEE 802.3af Power-Over-Ethernet
Interface/PWM Controller for Power Devices
ELECTRICAL CHARACTERISTICS (continued)
(VIN= (GND - VEE) = 48V, GATE = PGOOD= PGOOD = OPEN, V- tied to OUT, V+ tied to GND, UVLO = VEE, TA= TMINto TMAX,
unless otherwise noted. Typical values are at TA= +25°C. All voltages are referenced to VEE, unless otherwise noted.) (Note 1)
ELECTRICAL CHARACTERISTICS (PWMController)
(All voltages referenced to V-. VDD= 13V, a 10µF capacitor connects VCCto V-, VCS= V-, V+ = 48V, 0.1µF capacitor connected to
SS_SHDN, NDRV = open circuit, VFB= 3V, TA= TMINto TMAX, unless otherwise noted. Typical values are at TA= +25°C.) (Note 1)
MAX5942A/MAX5942B
IEEE 802.3af Power-Over-Ethernet
Interface/PWM Controller for Power Devices
ELECTRICAL CHARACTERISTICS (PWMController) (continued)
(All voltages referenced to V-. VDD= 13V, a 10µF capacitor connects VCCto V-, VCS= V-, V+ = 48V, 0.1µF capacitor connected to
MAX5942A/MAX5942B
IEEE 802.3af Power-Over-Ethernet
Interface/PWM Controller for Power Devices
ELECTRICAL CHARACTERISTICS (PWMController) (continued)
(All voltages referenced to V-. VDD= 13V, a 10µF capacitor connects VCCto V-, VCS= V-, V+ = 48V, 0.1µF capacitor connected to
SS_SHDN, NDRV = open circuit, VFB= 3V, TA= TMINto TMAX, unless otherwise noted. Typical values are at TA= +25°C.) (Note 1)
Note 1:All min/max limits for the PD interface are production tested at +85°C (extended grade)/+70°C (commercial grade). Limits
at +25°C and -40°C are guaranteed by design. All PWM controller min/max limits are 100% production tested at +25°C
and +85°C (extended grade)/+70°C (commercial grade). Limits at -40°C are guaranteed by design, unless otherwise
noted.
Note 2:The input offset current is illustrated in Figure 1.
Note 3:Effective differential input resistance is defined as the differential resistance between GND and VEEwithout any external
resistance.
Note 4: Classification current is turned off whenever the IC is in power mode.
Note 5:See Table 2 in the PD Classification Modesection. RDISCand RCLmust be 100ppm or better.
Note 6:See Thermal Dissipation sectionfor details.
Note 7:When UVLO is connected to the midpoint of an external resistor-divider with a series resistance of 25.5kΩ(±1%), the turn-
on threshold set point for the power mode is defined by the external resistor-divider. Make sure the voltage on the UVLO
pin does not exceed its maximum rating of 8V when VINis at the maximum voltage.
Note 8:When the VUVLOis below VTH, G, UVLO,the MAX5942_ sets the turn-on voltage threshold internally (VUVLO,ON).
Note 9:An input voltage or VUVLOglitch below their respective thresholds shorter than or equal to tOFF_DLYwill not cause the
MAX5942A/MAX5942B to exit power-on mode (as long as the input voltage remains above an operable voltage level of 12V).
Note 10:PGOOD references to OUT while PGOODreferences to VEE.
Note 11:Guaranteed by design.
MAX5942A/MAX5942B
IEEE 802.3af Power-Over-Ethernet
Interface/PWM Controller for Power Devices
DETECTION CURRENT vs.
INPUT VOLTAGE
MAX5942A/B toc01
INPUT VOLTAGE (V)
DETECTION CURRENT (mA)642
CLASSIFICATION CURRENT
vs. INPUT VOLTAGE
MAX5942A/B toc02
INPUT VOLTAGE (V)
CLASSIFICATION CURRENT (mA)201530
EFFECTIVE DIFFERENTIAL INPUT
RESISTANCE vs. INPUT VOLTAGE
MAX5942A/B toc03
INPUT VOLTAGE (V)
EFFECTIVE DIFFERENTIAL INPUT RESISTANCE (M105
OFFSET CURRENT
vs. INPUT VOLTAGE
MAX5942A/B toc04
INPUT VOLTAGE (V)
OFFSET CURRENT (642910753
NORMALIZED UVLO
vs. TEMPERATURE
MAX5942A/B toc05
TEMPERATURE (°C)
NORMALIZED UVLO3510-15
PGOOD OUTPUT LOW VOLTAGE
vs. CURRENT
MAX5942A/B toc06
ISINK (mA)
PGOOD
(mV)1248
PGOOD OUTPUT LOW VOLTAGE
vs. CURRENT
MAX5942A/B toc07
ISINK (mA)
PGOOD
(mV)1284
OUT LEAKAGE CURRENT
vs. TEMPERATURE
MAX5942A/B toc08
OUT LEAKAGE CURRENT (nA)3510-15
INRUSH CURRENT CONTROL
(VIN = 12V)
MAX5942A/B toc09
VGATE
5V/div
IINRUSH
100mA/div
VOUT
10V/div
PGOOD
10V/div
1ms/divypical Operating Characteristics
(VIN= (GND - VEE) = 48V, GATE = PGOOD = PGOOD = OUT = OPEN, UVLO = VEE, VDD= 13V, NDRV floating, TA= TMINto TMAX.
Typical values are at TA= +25°C. All voltages are referenced to VEE(for graphs 1–11 in the Typical Operating Characteristics); all
voltages are referenced to V- (for graphs 12–30 in the Typical Operating Characteristics), unless otherwise noted.
MAX5942A/MAX5942B
IEEE 802.3af Power-Over-Ethernet
Interface/PWM Controller for Power Devices
INRUSH CURRENT CONTROL
(VIN = 48V)
MAX5942A/B toc10
VGATE
5V/div
IINRUSH
100mA/div
VOUT
50V/div
PGOOD
50V/div
2ms/div
INRUSH CURRENT CONTROL
(VIN = 67V)
MAX5942A/B toc11VGATE
5V/div
IINRUSH
100mA/div
VOUT
50V/div
PGOOD
50V/div
2ms/div
VSS_SHDN vs. TEMPERATURE
(AT THE END OF SOFT-START)
MAX5942 toc12
TEMPERATURE (°C)
SS_SHDN
(V) (NORMALIZED TO V
REF
= 2.4V)
MAX5942A
MAXIMUM DUTY CYCLE vs. TEMPERATURE
MAX5942 toc14
TEMPERATURE (°C)
MAX5942B
MAXIMUM DUTY CYCLE vs. TEMPERATURE
MAX5942 toc15
TEMPERATURE (°C)
MAXIMUM DUTY CYCLE (%)
V+ SUPPLY CURRENT
vs. TEMPERATURE
MAX5942 toc16
V+ SUPPLY CURRENT (mA)
SOFT-START SOURCE CURRENT
vs. TEMPERATURE
MAX5942 toc17
TEMPERATURE (°C)
SOFT-START SOURCE CURRENT (ypical Operating Characteristics (continued)
(VIN= (GND - VEE) = 48V, GATE = PGOOD = PGOOD = OUT = OPEN, UVLO = VEE, VDD= 13V, NDRV floating, TA= TMINto TMAX.
Typical values are at TA= +25°C. All voltages are referenced to VEE(for graphs 1–11 in the Typical Operating Characteristics); all
voltages are referenced to V- (for graphs 12–30 in the Typical Operating Characteristics), unless otherwise noted.
MAX5942A/MAX5942B
IEEE 802.3af Power-Over-Ethernet
Interface/PWM Controller for Power Devices
CS THRESHOLD VOLTAGE
vs. TEMPERATURE
MAX5942 toc20
TEMPERATURE (°C)
CS THRESHOLD VOLTAGE (V)
NDRV RESISTANCE
vs. TEMPERATURE
MAX5942 toc21
NDRV RESISTANCE (
TEMPERATURE (°C)
CURRENT-LIMIT DELAY
vs. TEMPERATURE
MAX5942 toc22
TEMPERATURE (°C)
CURRENT-LIMIT DELAY (ns)
VSS_SHDN vs. VDD
MAX5942 toc23
VDD (V)
SS_SHDN
(V)
NDRV FREQUENCY vs. VDD
MAX5942 toc24
VDD (V)
NDRV FREQUENCY (kHz)ypical Operating Characteristics (continued)
(VIN= (GND - VEE) = 48V, GATE = PGOOD = PGOOD = OUT = OPEN, UVLO = VEE, VDD= 13V, NDRV floating, TA= TMINto TMAX.
Typical values are at TA= +25°C. All voltages are referenced to VEE(for graphs 1–11 in the Typical Operating Characteristics); all
voltages are referenced to V- (for graphs 12–30 in the Typical Operating Characteristics), unless otherwise noted.
MAX5942A/MAX5942B
IEEE 802.3af Power-Over-Ethernet
Interface/PWM Controller for Power Devices
(AFTER STARTUP)
MAX5942 toc28
V+ VOLTAGE (V)
V+ LEAKAGE CURRENT (
V+ SUPPLY CURRENT vs.
V+ VOLTAGE
MAX5942 toc27
V+ VOLTAGE (V)
V+ SUPPLY CURRENT (mA)
VCC VOLTAGE vs. VCC CURRENT
MAX5942 toc29
VCC CURRENT (mA)
VOLTAGE (V)5101520
VCC VOLTAGE vs. VCC CURRENT
MAX5942 toc30
VCC CURRENT (mA)
VOLTAGE (V)ypical Operating Characteristics (continued)
(VIN= (GND - VEE) = 48V, GATE = PGOOD = PGOOD = OUT = OPEN, UVLO = VEE, VDD= 13V, NDRV floating, TA= TMINto TMAX.
Typical values are at TA= +25°C. All voltages are referenced to VEE(for graphs 1–11 in the Typical Operating Characteristics); all
voltages are referenced to V- (for graphs 12–30 in the Typical Operating Characteristics), unless otherwise noted.
MAX5942A/MAX5942B
IEEE 802.3af Power-Over-Ethernet
Interface/PWM Controller for Power Devices
MAX5942A/MAX5942B
Pin Description
MAX5942A/MAX5942B
IEEE 802.3af Power-Over-Ethernet
Interface/PWM Controller for Power Devices
MAX5942A/MAX5942B
Detailed Description
The MAX5942A/MAX5942B integrate a complete power
IC for powered devices (PD) in a power-over-ethernet
(PoE) system. The MAX5942A/MAX5942B provide PD
Interface and a compact DC-DC PWM controller suitable
for flyback and forward converters in either isolated or
nonisolated designs.
The MAX5942A/MAX5942B PD interface complies with
the IEEE 802.3af standard, providing the PD with a
detection signature, a classification signature, and an
integrated isolation switch with programmable inrush
current control. These devices also feature power-mode
undervoltage lockout (UVLO) with wide hysteresis, and
power-good status outputs.
An integrated MOSFET provides PD isolation during
detection and classification. The MAX5942A/MAX5942B
guarantee a leakage current offset of less than 10µA dur-
ing the detection phase. A programmable current limit
prevents high inrush current during power-on. The
devices feature power-mode UVLO with wide hysteresis
and long deglitch time to compensate for twisted-pair
cable resistive drop and to ensure glitch-free transition
between detection, classification, and power-on/off
phases. The MAX5942A/MAX5942B provide both active-
high (PGOOD) and active-low (PGOOD) outputs. Both
devices offer an adjustable UVLO threshold with a
default value compliant to the IEEE 802.3af standard.
The MAX5942A/MAX5942B are designed to work with or
without an external diode bridge in front of the PD.
Use the MAX5942A/MAX5942B PWM current-mode con-
trollers to design flyback- or forward-mode power sup-
plies. Current-mode operation simplifies control-loop
design while enhancing loop stability. An internal high-
voltage startup regulator allows the device to connect
directly to the input supply without an external startup
resistor. Current from the internal regulator starts the con-
troller. Once the tertiary winding voltage is established,
the internal regulator is switched off and bias current
for running the PWM controller is derived from the
tertiary winding. The internal oscillator is set to 275kHz
and trimmed to ±10%. This permits the use of small
magnetic components to minimize board space. Both the
MAX5942A and MAX5942B can be used in power sup-
plies providing multiple output voltages. A functional dia-
gram of the PWM controller is shown in Figure 4. Typical
application circuits for forward and flyback topologies are
shown in Figure 5 and Figure 6, respectively.
Powered Device Interface
Operating Modes
The PD front-end section of the MAX5942A/MAX5942B
operates in three different modes: PD detection signa-
ture, PD classification, and PD power, depending on its
input voltage (VIN= GND - VEE). All voltage thresholds
are designed to operate with or without the optional
diode bridge while still complying with the IEEE 802.3af
standard (see Application Circuit 1).
Detection Mode (1.4V ≤VIN≤10.1V)
In detection mode, the power source equipment (PSE)
applies two voltages on VINin the range of 1.4V to
10.1V (1V step minimum), and then records the current
measurements at the two points. The PSE then com-
putes ∆V/∆I to ensure the presence of the 25.5kΩsig-
nature resistor. In this mode, most of the
MAX5942A/MAX5942B internal circuitry is off and the
offset current is less than 10µA.
If the voltage applied to the PD is reversed, install pro-
tection diodes on the input terminal to prevent internal
damage to the MAX5942A/MAX5942B (see Figures 8
and 9). Since the PSE uses a slope technique (∆V/∆I) to
calculate the signature resistance, the DC offset due to
the protection diodes is subtracted and does not affect
the detection process.
Classification Mode (12.6V ≤VIN≤20V)
In the classification mode, the PSE classifies the PD
based on the power consumption required by the PD.
This allows the PSE to efficiently manage power distribu-
tion. The IEEE 802.3af standard defines five different
classes as shown in Table 1. An external resistor (RCL)
connected from RCL to VEEsets the classification current.
MAX5942A/MAX5942B
IEEE 802.3af Power-Over-Ethernet
Interface/PWM Controller for Power Devices
MAX5942A/MAX5942B

Partno	Mfg	Dc	Qty	Available	Descript
MAX5942AESE	MAXIM	N/a	883	avai	IEEE 802.3af power-over-ethernet interface/PWM controller for power device
MAX5942BESE	MAXIM	N/a	857	avai	IEEE 802.3af power-over-ethernet interface/PWM controller for power device