19-5142; Rev 1; 9/10
TION KIT
EVALUA BLE
AVAILA
Single-Port, 40W, IEEE 802.3af/at PSE
Controller with Integrated MOSFET
Features
S
IEEE 802.3af/at Compliant
S
Up to 40W for Single-Port PSE Applications
S
Integrated 0.5I Power MOSFET and Sense
General Description
The MAX5971A is a single-port, power-sourcing equip-
ment (PSE) power controller designed for use in IEEE
®
802.3af/at-compliant PSE. This device provides powered
device (PD) discovery, classification, current limit, and
DC and AC load-disconnect detections. The MAX5971A
operates automatically without the need for any software
programming and features an integrated power MOSFET
and sense resistor. The device also supports new Class 5
and 2-event classification for detection and classification
of high-power PDs. The MAX5971A provides up to 40W
to a single port (Class 5 enabled) and still provides high-
capacitance detection for legacy PDs.
The MAX5971A provides input undervoltage lockout
(UVLO), input overvoltage lockout, overtemperature
detection, output voltage slew-rate limit during startup,
and LED status indication.
The MAX5971A is available in a space-saving, 28-pin
TQFN (5mm x 5mm) power package, and is rated for the
extended (-40NC to +85NC) temperature range.
MAX5971A
Resistor
S
PD Detection and Classification
S
Programmable Current Limit for Class 5 PDs
S
High-Capacitance Detection for Legacy Devices
S
Supports Both DC and AC Load Removal
Detections
S
Current Foldback and Duty Cycle-Controlled
Current Limit
S
LED Indicator for Port Status
S
Direct Fast-Shutdown Control Capability
S
Space-Saving, 28-Pin TQFN (5mm x 5mm)
Package
Ordering Information
PART
MAX5971AETI+
TEMP RANGE
-40NC to +85NC
PIN-PACKAGE
28 TQFN-EP*
Applications
Single-Port PSE End-Point Applications
Single-Port PSE Power Injectors (Midspan
Applications)
Switches/Routers
Industrial Automation Equipment
Wireless LAN Access Point/WiMAX™ Base
Station
+Denotes
a lead(Pb)-free/RoHS-compliant package.
*EP = Exposed pad.
Typical Operating Circuit
PSE OUTPUT
AGND
OUT
OUTP
-54V
V
EE
V
EE_DIG
LED
PWMEN
LEGACY
MIDSPAN
OSC
EN
MAX5971A
DET
ILIM1
ILIM2
IEEE is a registered service mark of the Institute of Electrical
and Electronics Engineers, Inc.
WiMAX is a trademark of WiMAX Forum.
_______________________________________________________________
Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
Single-Port, 40W, IEEE 802.3af/802.3at PSE
Controller with Integrated MOSFET
MAX5971A
ABSOLUTE MAXIMUM RATINGS
(Voltages referenced to V
EE
, unless otherwise noted.)
AGND, DET, LED ..................................................-0.3V to +80V
OUT ......................................................-0.3V to (V
AGND
+ 0.3V)
OUTP .......................................................-6V to (V
AGND
+ 0.3V)
VEE_DIG ...............................................................-0.3V to +0.3V
OSC .........................................................................-0.3V to +6V
EN, PWMEN, MIDSPAN, LEGACY, ILIM1, ILIM2 ....-0.3V to +4V
Maximum Current Into LED ................................................40mA
Maximum Current Into OUT ......................... Internally regulated
Continuous Power Dissipation (T
A
= +70NC)
28-Pin TQFN (derate 34.5mW/NC above +70NC) ......2758mW
Package Thermal Resistance (Note 1)
B
JA ...............................................................................29NC/W
B
JC ................................................................................2NC/W
Operating Temperature Range .......................... -40NC to +85NC
Storage Temperature Range............................ -65NC to +150NC
Junction Temperature .....................................................+150NC
Lead Temperature (soldering, 10s) ................................+300NC
Soldering Temperature (reflow) ......................................+260NC
Note 1:
Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-
layer board. For detailed information on package thermal considerations, refer to
www.maxim-ic.com/thermal-tutorial.
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.
ELECTRICAL CHARACTERISTICS
(V
AGND
- V
EE
= 32V to 60V, T
A
= -40NC to +85NC, all voltages are referenced to V
EE
, unless otherwise noted. Typical values are at
V
AGND
- V
EE
= +54V, T
A
= +25NC. Currents are positive when entering the pin and negative otherwise.) (Note 2)
PARAMETER
POWER SUPPLIES
Operating Voltage Range
Supply Current
CURRENT LIMIT
Maximum
I
LOAD
allowed
during
current-limit
conditions,
V
OUT
= 0V
(Note 3)
Class 0, 1, 2, 3
Class 4
Class 5 if ILIM1 = V
EE
, ILIM2
= unconnected
Class 5 if ILIM1 = uncon-
nected, ILIM2 = V
EE
Class 5 if ILIM1 = V
EE
, ILIM2
= V
EE
400
684
807
855
902
420
720
850
900
950
27
10
166
441
756
893
mA
945
998
V
V
mA
V
AGND
I
EE
V
AGND
- V
EE
V
OUT
= V
EE
, all logic inputs unconnected,
measured at AGND in power mode
32
2.5
60
4
V
mA
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Current Limit
I
LIM
Foldback Initial OUT Voltage
Foldback Final OUT Voltage
Minimum Foldback Current Limit
Threshold
V
FLBK_ST
V
FLBK_END
I
TH_FB
V
AGND
- V
OUT
below which the current
limit starts folding back
V
AGND
- V
OUT
below which the current
limit reaches I
TH_FB
V
OUT
= V
AGND
2
______________________________________________________________________________________
Single-Port, 40W, IEEE 802.3af/802.3at PSE
Controller with Integrated MOSFET
ELECTRICAL CHARACTERISTICS (continued)
(V
AGND
- V
EE
= 32V to 60V, T
A
= -40NC to +85NC, all voltages are referenced to V
EE
, unless otherwise noted. Typical values are at
V
AGND
- V
EE
= +54V, T
A
= +25NC. Currents are positive when entering the pin and negative otherwise.) (Note 2)
PARAMETER
OVERCURRENT
Class 0, 1, 2, 3
Overcurrent
threshold
allowed for
t
P
t
FAULT
,
V
OUT
= 0V
(Note 3)
Class 4
Class 5 if ILIM1 = V
EE
,
ILIM2 = unconnected
Class 5 if ILIM1 =
unconnected, ILIM2 = V
EE
Class 5 if ILIM1 = V
EE
,
ILIM2 = V
EE
351
602
710
752
794
370
634
748
792
836
389
666
785
mA
832
878
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
MAX5971A
Overcurrent Threshold
I
CUT
INTERNAL POWER
Measured
from OUT to
V
EE
, I
OUT
=
100mA
T
A
= +25NC
T
A
= +85NC
0.5
0.6
0.9
I
1.3
10
28.5
3
62.5
1
Port is shutdown and device resets if the
junction temperature exceeds this limit,
temperature increasing
Temperature decreasing
V
OUT
= V
AGND
, probing phases
OUTP discharge current, detection and
classification off, port shutdown,
V
OUTP
= V
AGND
- 2.8V
V
OUT
- V
EE,
V
OUT
decreasing, enabled
during detection
200
FA
V
V
V
V
DMOS On-Resistance
R
DS(ON)
Power-Off OUT Leakage Current I
OUT_LEAK
SUPPLY MONITORS
V
EE
Undervoltage Lockout
V
EE
Undervoltage Lockout
Hysteresis
V
EE
Overvoltage Lockout
V
EE
Overvoltage Lockout
Hysteresis
Thermal Shutdown Threshold
Thermal Shutdown Hysteresis
OUTPUT MONITOR
OUT Input Current
Idle Pullup Current at OUT
Short to V
EE
Detection
Threshold
Short to V
EE
Detection
Threshold Hysteresis
LOAD DISCONNECT
DC Load-Disconnect Threshold
I
DCTH
I
BOUT
I
DIS
V
EE_UVLO
V
EE_UVLOH
V
EE_OV
V
EE_OVH
V
EN
= V
EE
, V
OUT
= V
AGND
V
AGND
- V
EE
, V
AGND
increasing
Port is shutdown if: V
AGND
- V
EE
< V
EE_
UVLO
- V
EE_UVLOH
V
AGND
- V
EE
> V
EE_OV
, V
AGND
increasing
T
SHD
T
SHDH
150
20
6
265
NC
NC
FA
FA
DCN
TH
DCN
HY
1.5
2.0
220
2.5
V
mV
Minimum load current allowed before dis-
connect (DC disconnect active),
V
OUT
= 0V
Current into DET, for I
DET
< I
ACTH
the
port powers off (AC disconnect active)
5
7.5
10
mA
AC Load-Disconnect Threshold
I
ACTH
115
130
145
FA
_______________________________________________________________________________________
3
Single-Port, 40W, IEEE 802.3af/802.3at PSE
Controller with Integrated MOSFET
MAX5971A
ELECTRICAL CHARACTERISTICS (continued)
(V
AGND
- V
EE
= 32V to 60V, T
A
= -40NC to +85NC, all voltages are referenced to V
EE
, unless otherwise noted. Typical values are at
V
AGND
- V
EE
= +54V, T
A
= +25NC. Currents are positive when entering the pin and negative otherwise.) (Note 2)
PARAMETER
Triangular Wave Peak-to-Peak
Voltage Amplitude
OSC Pullup/Pulldown Currents
ACD_EN Threshold
SYMBOL
AMP
TRW
I
OSC
V
ACD_EN
CONDITIONS
Measured at DET, referred to AGND
Measured at OSC
V
OSC
- V
EE
> V
ACD_EN
to activate AC
disconnect
Time from I
RSENSE
< I
DCTH
(DC discon-
nect active) or I
DET
< I
ACTH
(AC discon-
nect active) to gate shutdown
V
AGND
- V
DET
during the first detection
phase
V
AGND
- V
DET
during the second detec-
tion phase
V
DET
= V
AGND
during detection, measure
current through DET
If V
AGND
- V
OUT
< V
DCP
after the first
detection phase a short circuit to AGND
is detected.
First point measurement current threshold
for open condition
(Note 4)
Detection rejects lower values
Detection rejects higher values
V
AGND
- V
DET
during classification
V
DET
= V
AGND
, during classification mea-
sure current through DET
Classification
current
thresholds
between
classes
Class 0, Class 1
Class 1, Class 2
Class 2, Class 3
Class 3, Class 4
Class 4 upper limit (Note 5)
32
16
65
5.5
13.0
21
31
45
8
55
6.5
14.5
23
33
48
20
80
7.5
16.0
25
35
51
10
80
V
mA
mA
19
MIN
3.85
26
270
TYP
4
32
330
MAX
4.2
39
380
UNITS
V
FA
mV
Load Disconnect Timer
DETECTION
Detection Probe Voltage
(First Phase)
Detection Probe Voltage
(Second Phase)
Current-Limit Protection
t
DISC
300
400
ms
V
DPH1
V
DPH2
I
DLIM
3.8
9
1.50
4
9.3
1.75
4.2
9.6
2.00
V
V
mA
Short-Circuit Threshold
V
DCP
1
V
Open-Circuit Threshold
Resistor Detection Window
Resistor Rejection Window
CLASSIFICATION
Classification Probe Voltage
Current-Limit Protection
I
D_OPEN
R
DOK
R
DBAD
20
26.5
15.5
FA
kI
kI
V
CL
I
ClLIM
V
mA
Classification Current
Thresholds
I
CL
Mark Event Voltage
Mark Event Current Limit
V
MARK
I
MARK_LIM
V
AGND
- V
DET
during mark event
V
DET
= V
AGND
, during mark event mea-
sure current through DET
4
______________________________________________________________________________________
Single-Port, 40W, IEEE 802.3af/802.3at PSE
Controller with Integrated MOSFET
ELECTRICAL CHARACTERISTICS (continued)
(V
AGND
- V
EE
= 32V to 60V, T
A
= -40NC to +85NC, all voltages are referenced to V
EE
, unless otherwise noted. Typical values are at
V
AGND
- V
EE
= +54V, T
A
= +25NC. Currents are positive when entering the pin and negative otherwise.) (Note 2)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
0.8
2.4
Pullup current to internal digital supply to
set default values
I
LED
= 10mA, PWM disabled, port power-on
PWM disabled, shutdown mode,
V
LED
= 60V
25
6.25
Time during which a current limit set to
420mA is allowed, starts when power is
turned on
Maximum allowed time for an overcurrent
condition set by I
CUT
after startup
Time allowed for the port voltage to reset
before detection starts
Maximum time allowed before detection is
completed
2
Time allowed for classification
Time allowed for mark event
t
DLY
t
RESTART
Time V
AGND
must be above the V
EEUVLO
thresholds before the device operates
Time the device waits before turning on
after an overcurrent fault
7
2.2
19
9
5.2
16 x
t
FAULT
3
5
7
0.8
10
UNITS
V
V
FA
V
FA
kHz
%
DIGITAL INPUTS/OUTPUTS (Voltages referenced to V
EE
)
Digital Input Low
V
IL
Digital Input High
Internal Input Pullup Current
LED Output Low Voltage
LED Output Leakage
PWM Frequency
PWM Duty Cycle
TIMING
Startup Time
t
START
50
60
70
ms
V
IH
I
PU
V
LED_LOW
I
LED_LEAK
MAX5971A
Fault Time
Detection Reset Time
Detection Time
Midspan Mode Detection Delay
Classification Time
Mark Event Time
V
EEUVLO
Turn-On Delay
Restart Timer
t
FAULT
t
ME
t
DET
t
DMID
t
CLASS
50
60
80
70
90
330
2.4
23
11
ms
ms
ms
s
ms
ms
ms
ms
Note 2:
This device is production tested at T
A
= +25NC. Limits at T
A
= -40NC and +85NC are guaranteed by design.
Note 3:
If ILIM1 and ILIM2 are both unconnected, Class 5 detection is disabled. See the
Class 5 PD Classification
section and Table 3 for
details and settings.
Note 4:
R
DOK
= (V
OUT2
- V
OUT1
)/(I
DET2
- I
DET1
). V
OUT1
, V
OUT2
, I
DET2
, and I
DET1
represent the voltage at OUT and the current at
DET during phase 1 and 2 of the detection, respectively.
Note 5:
If Class 5 is enabled, this is the classification current thresholds from Class 4 to Class 5.
_______________________________________________________________________________________
5
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