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MAX5941ACSE+

P1-P3P4-P6P7-P9P10-P12P13-P15P16-P18P19-P21P22-P24
General Description
The MAX5941A/MAX5941B integrate a complete power
IC for powered devices (PD) in a power-over-ethernet
(PoE) system. The MAX5941A/MAX5941B provide a PD
interface and a compact DC-DC PWM controller suitable
for flyback and forward converters in either isolated or
nonisolated designs.
The MAX5941A/MAX5941B 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 MAX5941A/MAX5941B also integrate all the building
blocks necessary for implementing DC-DC fixed-
frequency isolated power supplies. These devices are 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 fre-
quency is internally trimmed to 275kHz ±10%, thus
reducing magnetics and filter components. The
MAX5941A allows an 85% operating duty cycle and can
be used to implement flyback converters. The MAX5941B
limits the operating duty cycle to less than 50% and can
be used in single-ended forward converters. The
MAX5941A/MAX5941B are designed to work with or with-
out an external diode bridge in front of the PD.
The MAX5941A/MAX5941B are available in 16-pin SO
packages.
Applications
IP Phones
Wireless Access Nodes
Internet Appliances
Computer Telephony
Security Cameras
Power Devices in Power-Over-Ethernet/
Power-Over-MDI
Features
♦ Powered 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
Programmable Undervoltage Lockout
♦ PWM Controller
Wide Input Range: 18V to 67V
Current-Mode Control
Leading-Edge Blanking
Internally Trimmed 275kHz ±10% Oscillator
Soft-Start
MAX5941A/MAX5941B
IEEE 802.3af-Compliant Power-Over-Ethernet
Interface/PWM Controller for Power Devices
________________________________________________________________ Maxim Integrated Products 1
Ordering Information
19-3069; Rev 4; 6/06
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
PART
TEMP RANGE
PIN-
PACKAGE
M A X D U T Y
C YC L E ( % )
MAX5941AESE
-40°C to +85°C 16 SO (S16M-6)
85
MAX5941ACSE
0°C to +70°C 16 SO (S16M-6)
85
MAX5941BESE
-40°C to +85°C 16 SO (S16M-6)
50
MAX5941BCSE
0°C to +70°C 16 SO (S16M-6)
50
Typical Operating Circuit appears at end of data sheet.
16
15
14
13
12
11
10
9
1
2
3
4
5
6
7
8
V+
V
CC
NDRV
V-
CS
GND
PGOOD
PGOOD
OUT
TOP VIEW
MAX5941A
MAX5941B
SO
V
DD
OPTO
RCL
SS_SHDN
ULVO
GATE
V
EE
Pin Configuration
EVALUATION KIT
AVAILABLE
MAX5941A/MAX5941B
IEEE 802.3af-Compliant Power-Over-Ethernet
Interface/PWM Controller for Power Devices
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(V
IN
= (GND - V
EE
) = 48V, GATE = PGOOD = PGOOD = OPEN, V- tied to OUT, V+ tied to GND, UVLO = V
EE
, T
A
= T
MIN
to +T
MAX
,
unless otherwise noted. Typical values are at T
A
= +25°C. All voltages are referenced to V
EE
, unless otherwise noted.) (Note 1)
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 V
EE
, unless otherwise noted.)
GND........................................................................-0.3V to +90V
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 +90V
V
DD
to V-.................................................................-0.3V to +40V
V
CC
to V-..............................................................-0.3V to +12.5V
OPTO, NDRV, SS_SHDN, CS to V-.............-0.3V to (V
CC
+ 0.3V)
Maximum Input/Output Current (Continuous)
OUT to V
EE
...................................................................500mA
GND, RCL to V
EE
............................................................70mA
UVLO, PGOOD, PGOOD to V
EE
.....................................20mA
GATE to V
EE
....................................................................80mA
V
DD
, V
CC
.........................................................................20mA
NDRV Continuous ...........................................................25mA
NDRV (Pulsed for less than 1µs) .......................................±1A
Continuous Power Dissipation (T
A
= +70°C)
16-Pin SO (derate 9.1mW/°C above +70°C)................727mW
Operating Temperature Range
MAX5941_CSE ..................................................0°C to +70°C
MAX5941_ESE ...............................................-40°C to +85°C
Storage Temperature Range .............................-65°C to +150°C
Junction Temperature......................................................+150°C
Lead Temperature (soldering, 10s) ................................+300°C
PARAMETER
CONDITIONS MIN
TYP
MAX
UNITS
PD INTERFACE
DETECTION MODE
Input Offset Current I
OFFSET
V
I N
= 1.4V to 10.1V , G N D = V - = OU T = V +
(Note 2)
10 µA
Effective Differential Input
Resistance
dR
V
I N
= 1.4V up to 10.1V w i th 1V step , OU T =
P GO OD = GN D = O U T = V + ( N ote 3)
550
kΩ
CLASSIFICATION MODE
Classification Current Turn-Off
Threshold
V
TH
CLSS
V
IN
rising (Note 4)
20.8 21.8 22.5
V
Class 0, R
CL
= 10kΩ 02
Class 1, R
CL
= 732Ω
9.17 11.83
Class 2, R
CL
= 392Ω
17.29 19.71
Class 3, R
CL
= 255Ω
26.45 29.55
Classification Current (Notes 5, 6) I
CLASS
V
IN
= 12.6V
to 20V, R
DISC
= 25.5kΩ
Class 4, R
CL
= 178Ω
36.6 41.4
mA
POWER MODE
Operating Supply Voltage V
IN
V
IN
= (GND - V
EE
)67V
Operating Supply Current I
IN
Measure at GND, not including R
DISC
0.4 1
mA
Default Power Turn-On Voltage
V
UVLO
ON
V
IN
increasing, UVLO = V
EE
37.4 38.6 40.1
V
Default Power Turn-Off Voltage
V
UVLO
OFF
V
IN
decreasing, UVLO = V
EE
30 V
Default Power Turn-On/Off
Hysteresis
V
HYST,
UVLO
7.4 V
External UVLO Programming
Range
V
IN,EX
Set UVLO externally (Note 7) 12 67 V
UVLO External Reference Voltage
V
REF
UVLO
V
UVLO
increasing
2.400 2.460 2.522
V
MAX5941A/MAX5941B
IEEE 802.3af-Compliant Power-Over-Ethernet
Interface/PWM Controller for Power Devices
_______________________________________________________________________________________ 3
PARAMETER
SYMBOL
CONDITIONS MIN
TYP MAX
UNITS
UVLO External Reference Voltage
Hysteresis
HYST Ratio to V
REF,UVLO
19.2
20
20.9
%
UVLO Bias Current I
UVLO
UVLO = 2.460V -1.5
+1.5
µA
UVLO Input Ground Sense
Threshold
V
TH
G
UVLO
(Note 8) 50 440
mV
UVLO Input Ground Sense Glitch
Rejection
UVLO = V
EE
7µs
Power Turn-Off Voltage,
Undervoltage Lockout Deglitch
Time
t
OFF_DLY
V
IN
, V
UVLO
falling (Note 9)
0.32
ms
T
A
= +25°C
(Note 11)
0.6 1.1
Isolation Switch N-Channel
MOSFET On-Resistance
R
ON
Output current =
300mA, V
GATE
= 5.6V,
measured between
OUT and V
EE
T
A
= +85°C 0.8 1.5
Ω
Isolation Switch N-Channel
MOSFET Off-Threshold Voltage
V
GSTH
OUT = GND, V
GATE
- V
EE
,
output current
< 1µA
0.5 V
GATE Pulldown Switch Resistance
R
G
Power-off mode, V
IN
= 12V, UVLO = V
EE
38 80 Ω
GATE Charging Current I
G
V
GATE
= 2V 5 10 15 µA
GATE High Voltage V
GATE
I
GATE
= 1µA
5.58 5.76 5.93
V
V
OUT
- V
EE
, |V
OUT
- V
EE
| decreasing,
V
GATE
= 5.75V
1.15 1.23 1.31
V
PGOOD, PGOOD Assertion V
OUT
Threshold
V
OUTEN
Hysteresis 70
mV
(GATE - V
EE
) increasing, OUT = V
EE
4.62 4.76 4.91
V
PGOOD, PGOOD Assertion V
GATE
Threshold
V
GSEN
Hysteresis 80
mV
PGOOD Output Low Voltage I
SINK
= 2mA (Note 10) 0.4 V
PGOOD Output Low Voltage
V
OLDCDC
I
SINK
= 2mA, OUT ≤ (GND - 5V) (Note 10)
0.2 V
PGOOD Leakage Current
G ATE = hi g h, GN D - V
OU T
= 67V ( N ote 10)
1µA
PGOOD Leakage Current
GATE = V
E E
, PGO OD - V
E E
= 67V ( N ote 10)
1µA
ELECTRICAL CHARACTERISTICS (continued)
(V
IN
= (GND - V
EE
) = 48V, GATE = PGOOD = PGOOD = OPEN, V- tied to OUT, V+ tied to GND, UVLO = V
EE
, T
A
= T
MIN
to +T
MAX
,
unless otherwise noted. Typical values are at T
A
= +25°C. All voltages are referenced to V
EE
, unless otherwise noted.) (Note 1)
ELECTRICAL CHARACTERISTICS (PWM Controller)
(All voltages referenced to V-. V
DD
= 13V, a 10µF capacitor connects V
CC
to V-, V
CS
= V-, V+ = 48V, 0.1µF capacitor connected to
SS_SHDN, NDRV = open circuit, OPTO = V-, T
A
= T
MIN
to +T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.) (Note 1)
PARAMETER
SYMBOL
CONDITIONS
MIN TYP MAX
UNITS
SUPPLY CURRENT
I
V+(NS)
V
DD
= 0V, V+ = 67V, driver not switching
0.85
1.3
V+ Supply Current
I
V+(S)
V+ = 67V, V
DD
= 0V, V
OPTO
= 4V, driver
switching
1.4 2.6
mA
V+ Supply Current After Startup V+ = 67V, V
DD
= 13V, V
OPTO
= 4V 11 µA
I
VDD
(
NS
)
V
DD
= 36V, driver not switching 0.9 1.3
V
DD
Supply Current
I
VDD(S)
V
DD
= 36V, driver switching, V
OPTO
= 4V 1.9 2.7
mA
P1-P3P4-P6P7-P9P10-P12P13-P15P16-P18P19-P21P22-P24

MAX5941ACSE+

Mfr. #:
Buy MAX5941ACSE+
Manufacturer:
Maxim Integrated
Description:
Power Switch ICs - POE / LAN IEEE 802.3af POE Int/PWM Controller
Lifecycle:
New from this manufacturer.
Delivery:
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