MAXIM MAX5965BUAX+

19-4593; Rev 1; 1/10
High-Power, Quad, Monolithic, PSE Controllers
for Power over Ethernet
The MAX5965A/MAX5965B are quad, monolithic, -48V
power controllers designed for use in IEEE® 802.3af-compliant/pre-IEEE 802.3at-compatible power-sourcing equipment (PSE). These devices provide powered device (PD)
discovery, classification, current limit, DC and AC load disconnect detections in compliance with the IEEE 802.3af
standard. The MAX5965A/MAX5965B are pin compatible
with the MAX5952/MAX5945/LTC4258/LTC4259A PSE
controllers and provide additional features.
The MAX5965A/MAX5965B feature a high-power mode
that provides up to 45W per port. The MAX5965A/
MAX5965B provide new Class 5 and 2-event classification (Class 6) for detection and classification of highpower PDs. The MAX5965A/MAX5965B provide
instantaneous readout of each port current through the
I2C interface. The MAX5965A/MAX5965B also provide
high-capacitance detection for legacy PDs.
These devices feature an I2C-compatible, 3-wire serial interface, and are fully software configurable and programmable.
The class-overcurrent detection function enables system
power management to detect if a PD draws more than the
allowable current. The MAX5965A/MAX5965B’s extensive
programmability enhances system flexibility, enables field
diagnosis, and allows for uses in other applications.
The MAX5965A/MAX5965B provide four operating modes
to suit different system requirements. Auto mode allows
the devices to operate automatically without any software
supervision. Semi-automatic mode automatically detects
and classifies a device connected to a port after initial
software activation, but does not power up that port until
instructed to by software. Manual mode allows total software control of the device and is useful for system diagnostics. Shutdown mode terminates all activities and
securely turns off power to the ports.
The MAX5965A/MAX5965B provide input undervoltage
lockout (UVLO), input undervoltage detection, a loadstability safety check during detection, input overvoltage lockout, overtemperature detection, output voltage
slew-rate limit during startup, power-good status, and
fault status. The MAX5965A/MAX5965B’s programmability includes startup timeout, overcurrent timeout, and
load-disconnect detection timeout.
Features
o IEEE 802.3af Compliant/Pre-IEEE 802.3at
Compatible
o Instantaneous Readout of Port Current Through
I2C Interface
o High-Power Mode Enables Up to 45W Per Port
o High-Capacitance Detection for Legacy Devices
o Pin Compatible with MAX5952/MAX5945/
LTC4258/LTC4259A
o Four Independent Power-Switch Controllers
o PD Detection and Classification (Including 2Event Classification)
o Selectable Load-Stability Safety Check During
Detection
o Supports Both DC and AC Load Removal
Detections
o I2C-Compatible, 3-Wire Serial Interface
o Current Foldback and Duty-Cycle-Controlled
Current Limit
o Open-Drain INT Signal
o Direct Fast Shutdown Control Capability
o Special Class 5 Classification
Ordering Information
TEMP RANGE
PIN-PACKAGE
MAX5965AEAX+
PART
-40°C to +85°C
36 SSOP
MAX5965AUAX+*
0°C to +85°C
36 SSOP
MAX5965BEAX+
-40°C to +85°C
36 SSOP
MAX5965BUAX+*
0°C to +85°C
36 SSOP
+Denotes a lead(Pb)-free/RoHS-compliant package.
*Future product—contact factory for availability.
Selector Guide
PART
PIN-PACKAGE
AC DISCONNECT
FEATURE
The MAX5965A/MAX5965B are available in a 36-pin SSOP
package and are rated for both extended (-40°C to +85°C)
and upper commercial (0°C to +85°C) temperature ranges.
MAX5965AEAX+
36 SSOP
MAX5965AUAX+
36 SSOP
No
Applications
MAX5965BEAX+
36 SSOP
Yes
MAX5965BUAX+
36 SSOP
Yes
Power-Sourcing Equipment (PSE)
Switches/Routers
Midspan Power Injectors
No
Pin Configuration appears at end of data sheet.
IEEE is a registered service mark of the Institute of Electrical and Electronics Engineers, Inc.
________________________________________________________________ Maxim Integrated Products
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.
1
MAX5965A/MAX5965B
General Description
MAX5965A/MAX5965B
High-Power, Quad, Monolithic, PSE Controllers
for Power over Ethernet
ABSOLUTE MAXIMUM RATINGS
(Voltages referenced to VEE, unless otherwise noted.)
AGND, DGND, DET_, VDD, RESET, A3–A0, SHD_, OSC,
SCL, SDAIN, AUTO .............................................-0.3V to +80V
OUT_........................................................-12V to (AGND + 0.3V)
GATE_ (internally clamped) (Note 1) ..................-0.3V to +11.4V
SENSE_ ..................................................................-0.3V to +24V
VDD, RESET, MIDSPAN, A3–A0, SHD_, OSC, SCL,
SDAIN and AUTO to DGND ..................................-0.3V to +7V
INT and SDAOUT to DGND....................................-0.3V to +12V
Maximum Current into INT, SDAOUT, DET_ .......................80mA
Maximum Power Dissipation (TA = +70°C)
36-Pin SSOP (derate 17.4mW/°C above +70°C) .....1388.9mW
Operating Temperature Ranges:
MAX5965A/MAX5965B_EAX ...…………………-40°C to +85°C
MAX5965A/MAX5965B_UAX ...............................0°C to +85°C
Storage Temperature Range .............................-65°C to +150°C
Junction Temperature ......................................................+150°C
Lead Temperature (soldering, 10s) .................................+300°C
Note 1: GATE_ is internally clamped to 11.4V above VEE. Driving GATE_ higher than 11.4V above VEE may damage the device.
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
(VAGND = 32V to 60V, VEE = 0V, VDD to VDGND = +3.3V, all voltages are referenced to VEE, unless otherwise noted. Typical values are at
VAGND = +48V, VDGND = +48V, VDD = (VDGND + 3.3V), TA = +25°C. Currents are positive when entering the pin and negative otherwise.) (Note 2)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
POWER SUPPLIES
VAGND
Operating Voltage Range
VDD
Supply Currents
VAGND - VEE
32
60
0
60
VDD to VDGND, VDGND = VAGND
2.4
3.6
VDD to VDGND, VDGND = VEE
3.0
3.6
VDGND
IEE
VOUT_ = VEE, VSENSE_ = VEE, DET_ = AGND,
all logic inputs open, SCL = SDAIN = VDD.
INT and SDAOUT unconnected. Measured at
AGND in power mode after GATE_ pullup
4.8
6.8
IDIG
All logic inputs high, measured at VDD
0.2
0.4
IPU
Power mode, gate drive on, VGATE_ = VEE
(Note 3)
-50
-65
V
mA
GATE DRIVER AND CLAMPING
GATE_ Pullup Current
-40
µA
Weak GATE_ Pulldown Current
IPDW
SHD_ = DGND, VGATE_ = VEE + 10V
42
µA
Maximum Pulldown Current
IPDS
VSENSE_ = 600mV, VGATE_ = VEE + 2V
100
mA
External Gate Drive
VGS
VGATE_ - VEE, power mode, gate drive on,
IPU = 1µA
2
9
10
_______________________________________________________________________________________
11.5
V
High-Power, Quad, Monolithic, PSE Controllers
for Power over Ethernet
(VAGND = 32V to 60V, VEE = 0V, VDD to VDGND = +3.3V, all voltages are referenced to VEE, unless otherwise noted. Typical values are at
VAGND = +48V, VDGND = +48V, VDD = (VDGND + 3.3V), TA = +25°C. Currents are positive when entering the pin and negative otherwise.) (Note 2)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
IVEE = 00
202
212
220
IVEE = 01
192
202
212
IVEE = 10
186
190
200
IVEE = 11
170
180
190
ICUT = 000
(Class 0/3)
177
186
196
ICUT =110
(Class 1)
47
55
64
ICUT = 111
(Class 2)
86
94
101
ICUT = 001
265
280
295
ICUT = 010
310
327
345
ICUT = 011
355
374
395
ICUT = 100
398
419
440
ICUT =101
443
466
488
UNITS
CURRENT LIMIT
Current-Limit Clamp Voltage
Overcurrent Threshold After
Startup
Foldback Initial OUT_ Voltage
Foldback Final OUT_ Voltage
Minimum Foldback
Current-Limit Threshold
SENSE_ Input Bias Current
VSU_LIM
VFLT_LIM
VFLBK_ST
Maximum VSENSE_ allowed
during current limit, VOUT_ = 0V
(ICUT = 000) (Note 4)
Overcurrent VSENSE_ threshold
allowed for t ≤ tFAULT after
startup; VOUT_ = 0V,
(IVEE = 00)
VOUT_ - VEE, above which the
current-limit trip voltage starts
folding back, IVEE = 00
mV
mV
ICUT = 000,
ICUT = 110,
ICUT = 111
32
ICUT =
001…101
13
V
IVEE = 00, ICUT = 000, VOUT_ - VEE above
VFLBK_END which the current-limit trip voltage reaches
VTH_FB
VTH_FB
VOUT_ = AGND = 60V, IVEE = 00, ICUT = 000
VSENSE_ = VEE
-5
50
V
64
mV
+5
µA
_______________________________________________________________________________________
3
MAX5965A/MAX5965B
ELECTRICAL CHARACTERISTICS (continued)
MAX5965A/MAX5965B
High-Power, Quad, Monolithic, PSE Controllers
for Power over Ethernet
ELECTRICAL CHARACTERISTICS (continued)
(VAGND = 32V to 60V, VEE = 0V, VDD to VDGND = +3.3V, all voltages are referenced to VEE, unless otherwise noted. Typical values are at
VAGND = +48V, VDGND = +48V, VDD = (VDGND + 3.3V), TA = +25°C. Currents are positive when entering the pin and negative otherwise.) (Note 2)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
SUPPLY MONITORS
VEE Undervoltage Lockout
VEE Undervoltage Lockout
Hysteresis
VEEUVLO
VEEUVLOH
VEE Overvoltage Lockout
VEE_OV
VEE Overvoltage Lockout
Hysteresis
VOVH
AGND - VEE, AGND - VEE increasing
Ports shut down if AGND - VEE < VUVLO VEEUVLOH
VEE_OV event bit sets and ports shut down if
AGND - VEE > VEE_OV, AGND increasing
28.5
V
3
V
62.5
V
1
V
40
V
VEE Undervoltage
VEE_UV
VEE_UV event bit is set if AGND - VEE < VEE_UV,
VEE increasing
VDD Overvoltage
VDD_OV
VDD_OV event bit is set if VDD - VDGND >
VDD_OV; VDD increasing
3.82
V
VDD Undervoltage
VDD_UV
VDD_UV is set if VDD - VDGND > VDD_UV, VDD
decreasing
2.7
V
2
V
120
mV
+150
°C
20
°C
VDD Undervoltage Lockout
VDDUVLO
VDD Undervoltage Lockout
Hysteresis
VDDHYS
Device operates when VDD - DGND >
VDDUVLO, VDD increasing
Ports shut down and device resets if its
junction temperature exceeds this limit,
temperature increasing (Note 5)
Thermal Shutdown Threshold
TSHD
Thermal Shutdown Hysteresis
TSHDH
Thermal hysteresis, temperature decreasing
(Note 5)
IBOUT
VOUT_ = AGND, all modes
OUTPUT MONITOR
OUT_ Input Current
Idle Pullup Current at OUT_
IDIS
PGOOD High Threshold
PGTH
PGOOD Hysteresis
PGHYS
PGOOD Low-to-High Glitch
Filter
4
tPGOOD
OUT_ discharge current, detection and
classification off, port shutdown, VOUT_ =
AGND - 2.8V
200
VOUT_ - VEE, OUT_ decreasing
1.5
Minimum time PGOOD has to be high to set
bit in register 10h
2.0
2
µA
265
µA
2.5
V
220
mV
3
ms
_______________________________________________________________________________________
High-Power, Quad, Monolithic, PSE Controllers
for Power over Ethernet
(VAGND = 32V to 60V, VEE = 0V, VDD to VDGND = +3.3V, all voltages are referenced to VEE, unless otherwise noted. Typical values are at
VAGND = +48V, VDGND = +48V, VDD = (VDGND + 3.3V), TA = +25°C. Currents are positive when entering the pin and negative otherwise.) (Note 2)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
DC Load Disconnect
Threshold
VDCTH
Minimum VSENSE_ allowed before disconnect
(DC disconnect active), VOUT_ = 0V
2.5
3.75
5.0
mV
AC Load Disconnect
Threshold
IACTH
Current into DET_, for I < IACTH the port
powers off, ACD_EN_ bit = H; VOSC = 2.2V,
MAX5965B (Note 6)
285
320
360
µA
Oscillator Buffer Gain
AOSC
VDET_/VOSC, ACD_EN_ bit = H, MAX5965B
2.9
3.0
3.1
V/V
VOSC_FAIL
Port does not power on if VOSC < VOSC_FAIL
and ACD_EN_ bit is high, MAX5965B (Note 7)
1.8
2.2
V
OSC Input Impedance
ZOSC
OSC input impedance when all the ACD_EN_
are active, MAX5965B
100
Load Disconnect Timer
tDISC
Time from VSENSE_ < VDCTH to gate shutdown
(Note 8)
300
Detection Probe Voltage
(First Phase)
VDPH1
AGND - VDET_ during the first detection
phase
3.8
Detection Probe Voltage
(Second Phase)
VDPH2
AGND - VDET_ during the second detection
phase
Current-Limit Protection
IDLIM
VDET_ = AGND, during detection, measure
current through DET_
Short-Circuit Threshold
VDCP
If AGND - VOUT_ < VDCP after the first
detection phase a short circuit to AGND is
detected
Open-Circuit Threshold
ID_OPEN
LOAD DISCONNECT
OSC Fail Threshold
kΩ
400
ms
4
4.2
V
9.0
9.3
9.6
V
1.5
1.8
2.2
mA
DETECTION
Resistor Detection Window
Resistor Rejection Window
RDOK
RDBAD
First point measurement current threshold for
open condition
(Note 9)
1
V
12.5
µA
19.0
26.5
Detection rejects lower values
Detection rejects higher values
15.2
32
kΩ
kΩ
CLASSIFICATION
Classification Probe Voltage
Current-Limit Protection
Classification Current
Thresholds
VCL
VAGND - VDET_ during classification
16
20
V
ICILIM
DET_ = AGND, during classification
68
80
mA
ICL
Classification current
thresholds between
classes
Class 0, Class 1
5.5
6.5
7.5
Class 1, Class 2
13
14.5
16
Class 2, Class 3
21
23
25
Class 3, Class 4
31
33
35
Class 4, Class 5
45
48
51
mA
_______________________________________________________________________________________
5
MAX5965A/MAX5965B
ELECTRICAL CHARACTERISTICS (continued)
MAX5965A/MAX5965B
High-Power, Quad, Monolithic, PSE Controllers
for Power over Ethernet
ELECTRICAL CHARACTERISTICS (continued)
(VAGND = 32V to 60V, VEE = 0V, VDD to VDGND = +3.3V, all voltages are referenced to VEE, unless otherwise noted. Typical values are at
VAGND = +48V, VDGND = +48V, VDD = (VDGND + 3.3V), TA = +25°C. Currents are positive when entering the pin and negative otherwise.) (Note 2)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
0.9
V
DIGITAL INPUTS/OUTPUTS (Referred to DGND)
Digital Input Low
VIL
Digital Input High
VIH
2.4
V
Internal Input Pullup/Pulldown
Resistor
RDIN
Pullup (pulldown) resistor to VDD (DGND) to
set default level
Open-Drain Output Low Voltage
VOL
ISINK = 15mA
0.4
V
Digital Input Leakage
IDL
Input connected to the pull voltage
2
µA
Open-Drain Leakage
IOL
Open-drain high impedance, VOUT_ = 3.3V
2
µA
25
50
75
kΩ
TIMING
Startup Time
tSTART
Time during which a current limit set by
VSU_LIM is allowed, starts when the GATE_ is
turned on (Note 9)
50
60
70
ms
Fault Time
tFAULT
Maximum allowed time for an overcurrent
condition set by VFLT_LIM after startup
(Note 9)
50
60
70
ms
Port Turn-Off Time
tOFF
Detection Reset Time
Detection Time
tDET
Midspan Mode Detection Delay
tDMID
Classification Time
tCLASS
VEEUVLO Turn-On Delay
Restart Timer
tDLY
tRESTART
Minimum delay between any port turning off,
does not apply in case of a reset
0.5
Time allowed for the port voltage to reset
before detection starts
80
Maximum time allowed before detection is
completed
2.0
Time allowed for classification
Time VAGND must be above the VEEUVLO
thresholds before the device operates
Time a port has to wait
before turning on after an
overcurrent fault during
normal operation,
RSTR_EN_ bits = high
tWD
2
RSTR bits = 00
16 x
tFAULT
RSTR bits = 01
32 x
tFAULT
RSTR bits = 10
RSTR bits = 11
Watchdog Clock Period
19
Rate of decrement of the watchdog timer
ms
90
ms
330
ms
2.4
s
23
ms
4
ms
ms
64 x
tFAULT
0
164
ms
9
Bits
0.51
V
ADC PERFORMANCE
Resolution
Range
LSB Step Size
Integral Nonlinearity (Relative)
6
1
INL
0.2
_______________________________________________________________________________________
mV
1.5
LSB
High-Power, Quad, Monolithic, PSE Controllers
for Power over Ethernet
(VAGND = 32V to 60V, VEE = 0V, VDD to VDGND = +3.3V, all voltages are referenced to VEE, unless otherwise noted. Typical values are at
VAGND = +48V, VDGND = +48V, VDD = (VDGND + 3.3V), TA = +25°C. Currents are positive when entering the pin and negative otherwise.) (Note 2)
PARAMETER
Differential Nonlinearity
SYMBOL
CONDITIONS
MIN
DNL
TYP
MAX
UNITS
0.2
1.5
LSB
3
%
305
LSB
400
kHz
Gain Error
ADC Absolute Accuracy
VSENSE_ = 300mV
295
300
TIMING CHARACTERISTICS (For 2-Wire Fast Mode)
Serial-Clock Frequency
fSCL
Bus Free Time Between a
STOP and START Condition
tBUF
1.2
µs
tHD, STA
0.6
µs
Low Period of the SCL Clock
tLOW
1.2
µs
High Period of the SCL Clock
Hold Time for a START
Condition
tHIGH
0.6
µs
Setup Time for a Repeated
START Condition (Sr)
tSU, STA
0.6
µs
Data Hold Time
tHD, DAT
100
Data in Setup Time
tSU, DAT
100
Rise Time of Both SDA and
SCL Signals, Receiving
tR
20 +
0.1CB
300
ns
Fall Time of SDA Transmitting
tF
20 +
0.1CB
300
ns
Setup Time for STOP Condition
tSU, STO
0.6
Capacitive Load for Each Bus
Line
CB
400
pF
Pulse Width of Spike
Suppressed
tSP
50
ns
300
ns
ns
µs
Limits to TA = -40°C are guaranteed by design.
Default values. The charge/discharge currents are programmable through the serial interface (see the Register Map and
Description section).
Note 4: Default values. The current-limit thresholds are programmed through the I2C-compatible serial interface (see the Register
Map and Description section).
Note 5: Functional test is performed over thermal shutdown entering test mode.
Note 6: This is the default value. Threshold can be programmed through serial interface R23h[2:0].
Note 7: AC disconnect works only if (VDD - VDGND) ≥ 3V and DGND is connected to AGND.
Note 8: tDISC can also be programmed through the serial interface (R16h) (see the Register Map and Description section).
Note 9: RD = (VOUT_2 - VOUT_1)/(IDET_2 - IDET_1). VOUT_1, VOUT_2, IDET_2, and IDET_1 represent the voltage at OUT_ and the current at DET_ during phase 1 and 2 of the detection.
Note 10: Default values. The startup and fault times can also be programmed through the I2C serial interface (see the Register Map
and Description section).
Note 2:
Note 3:
_______________________________________________________________________________________
7
MAX5965A/MAX5965B
ELECTRICAL CHARACTERISTICS (continued)
Typical Operating Characteristics
(VEE = -48V, VDD = +3.3V, VAUTO = VAGND = VDGND = 0V, RESET = SHD_ = unconnected, RSENSE = 0.5Ω, IVEE = 00, ICUT = 000,
TA = +25°C, all registers = default setting, unless otherwise noted.)
5.1
5.0
4.9
4.8
5.2
5.1
4.8
4.6
4.5
4.5
36
40
44
48
52
56
60
VEE = -48V
4.9
4.7
MEASURED AT VDD
125
VDD = 3.6V
120
115
VDD = 3.3V
110
105
VDD = 2.4V
VEE = -32V
100
-40
-15
10
35
60
85
-40
-15
10
35
TEMPERATURE (NC)
TEMPERATURE (NC)
DIGITAL SUPPLY CURRENT
vs. DIGITAL SUPPLY VOLTAGE
VEE UNDERVOLTAGE LOCKOUT
vs. TEMPERATURE
GATE OVERDRIVE
vs. INPUT VOLTAGE
120
115
110
29.0
28.5
28.0
27.5
100
27.0
MAX5965A toc06
29.5
105
10.10
10.08
10.06
GATE OVERDRIVE (V)
125
30.0
MAX5965A toc05
MEASURED AT VDD
85
60
VAGND - VEE (V)
MAX5965A toc04
32
VEE = -60V
5.0
4.6
130
SUPPLY CURRENT (FA)
5.3
4.7
130
SUPPLY CURRENT (FA)
5.2
5.4
UNDERVOLTAGE LOCKOUT (V)
SUPPLY CURRENT (mA)
5.3
5.5
MAX5965A toc02
MEASURED AT AGND
5.4
SUPPLY CURRENT (mA)
MAX5965A toc01
5.5
DIGITAL SUPPLY CURRENT
vs. TEMPERATURE
ANALOG SUPPLY CURRENT
vs. TEMPERATURE
MAX5965A toc03
ANALOG SUPPLY CURRENT
vs. INPUT VOLTAGE
10.04
10.02
10.00
9.98
9.96
9.94
9.92
2.8
3.0
3.2
3.4
3.6
-40
-15
10
35
60
36
40
10.10
10.05
10.00
9.95
9.90
48
52
56
60
56
60
SENSE TRIP VOLTAGE
vs. INPUT VOLTAGE
MAX5965A toc08
196
SENSE TRIP VOLTAGE (mV)
MAX5965A toc07
10.15
44
VAGND - VEE (V)
SENSE TRIP VOLTAGE
vs. TEMPERATURE
10.20
192
188
184
189.0
188.5
188.0
187.5
187.0
186.5
186.0
185.5
9.85
-40
-15
10
35
TEMPERATURE (NC)
8
32
TEMPERATURE (NC)
GATE OVERDRIVE
vs. TEMPERATURE
9.80
9.90
85
MAX5965A toc09
2.6
SENSE TRIP VOLTAGE (mV)
2.4
SUPPLY VOLTAGE (V)
GATE OVERDRIVE (V)
MAX5965A/MAX5965B
High-Power, Quad, Monolithic, PSE Controllers
for Power over Ethernet
60
85
180
-40
-15
10
35
TEMPERATURE (NC)
60
85
185.0
32
36
40
44
48
VAGND - VEE (V)
_______________________________________________________________________________________
52
High-Power, Quad, Monolithic, PSE Controllers
for Power over Ethernet
FOLDBACK CURRENT-LIMIT THRESHOLD
vs. OUTPUT VOLTAGE
200
150
100
ICUT = 001
400
350
300
250
200
ICUT = 001
150
100
50
50
0
0
10
20
30
40
0
50
0
10
VOUT - VEE (V)
20
30
40
50
6
MAX5965A toc11
MAX5965A toc10A
450
VSENSE - VEE (mV)
250
VSENSE - VEE (mV)
500
MAX5965A toc10
300
DC LOAD DISCONNECT THRESHOLD
vs. TEMPERATURE
DC LOAD DISCONNECT THRESHOLD (mV)
FOLDBACK CURRENT-LIMIT THRESHOLD
vs. OUTPUT VOLTAGE
5
4
3
2
-40
VOUT - VEE (V)
10
35
60
85
TEMPERATURE (NC)
OVERCURRENT TIMEOUT
(RLOAD = 240Ω TO 57Ω)
MAX5965A toc12
-15
OVERCURRENT RESPONSE WAVEFORM
(MAX5965AUAX) (RLOAD = 240Ω TO 57Ω)
MAX5965A toc13
(AGND - VOUT)
50V/div
0V
IOUT
200mA/div
(AGND - VOUT)
50V/div
0V
IOUT
200mA/div
0A
0V
VGATE_
10V/div
0A
VEE
VEE
INT
5V/div
0V
20ms/div
VGATE_
10V/div
INT
2V/div
400μs/div
SHORT-CIRCUIT RESPONSE TIME
SHORT-CIRCUIT RESPONSE TIME
MAX5965A toc15
MAX5965A toc14
(AGND - VOUT)
20V/div
(AGND - VOUT)
20V/div
0V
0V
IOUT
10A/div
IOUT
200mA/div
0A
130mA
VGATE_
10V/div
VGATE_
10V/div
VEE
20ms/div
VEE
4μs/div
_______________________________________________________________________________________
9
MAX5965A/MAX5965B
Typical Operating Characteristics (continued)
(VEE = -48V, VDD = +3.3V, VAUTO = VAGND = VDGND = 0V, RESET = SHD_ = unconnected, RSENSE = 0.5Ω, IVEE = 00, ICUT = 000,
TA = +25°C, all registers = default setting, unless otherwise noted.)
MAX5965A/MAX5965B
High-Power, Quad, Monolithic, PSE Controllers
for Power over Ethernet
Typical Operating Characteristics (continued)
(VEE = -48V, VDD = +3.3V, VAUTO = VAGND = VDGND = 0V, RESET = SHD_ = unconnected, RSENSE = 0.5Ω, IVEE = 00, ICUT = 000,
TA = +25°C, all registers = default setting, unless otherwise noted.)
RESET TO OUT TURN-OFF DELAY
ZERO-CURRENT DETECTION WAVEFORM
MAX5965A toc17
MAX5965A toc16
RESET
2V/div
(AGND - VOUT)
20V/div
0V
0V
IOUT
200mA/div
0A
VGATE_
10V/div
VEE
IOUT
200mA/div
0A
VGATE_
5V/div
INT
2V/div
VEE
0V
100ms/div
STARTUP WITH VALID PD
(25kI AND 0.1µF)
OVERCURRENT RESTART DELAY
MAX5965A toc19
MAX5965A toc18
VAGND - VOUT
20V/div
(AGND - VOUT)
20V/div
0V
0V
IOUT
100mA/div
IOUT
200mA/div
0A
0A
VGATE_
10V/div
VEE
VGATE_
5V/div
VEE
400ms/div
DETECTION WITH INVALID PD
(25kI AND 10µF)
DETECTION WITH INVALID PD (15kΩ)
MAX5965A toc21
MAX5965A toc20
VAGND - VOUT
20V/div
(AGND - VOUT)
5V/div
0V
0V
IOUT
1mA/div
0A
VGATE_
10V/div
VEE
IOUT
1mA/div
0A
100ms/div
10
______________________________________________________________________________________
High-Power, Quad, Monolithic, PSE Controllers
for Power over Ethernet
STARTUP IN MIDSPAN MODE
WITH VALID PD (25kI AND 0.1µF)
DETECTION WITH INVALID PD (33kΩ)
MAX5965A toc22
MAX5965A toc23
VAGND - VOUT
20V/div
(AGND - VOUT)
5V/div
0V
0V
IOUT
100mA/div
IOUT
1mA/div
0A
0A
VGATE_
5V/div
VEE
100ms/div
DETECTION WITH MIDSPAN MODE
WITH INVALID PD (33kΩ)
DETECTION WITH MIDSPAN MODE
WITH INVALID PD (15kΩ)
MAX5965A toc25
MAX5965A toc24
(AGND - VOUT)
5V/div
(AGND - VOUT)
5V/div
0V
0V
0A
IOUT
1mA/div
0A
IOUT
1mA/div
VEE
VGATE_
10V/div
VEE
VGATE_
10V/div
0V
400ms/div
400ms/div
OUTPUT SHORTED
DETECTION WITH INVALID PD (OPEN CIRCUIT,
USING TYPICAL OPERATING CIRCUIT 1)
MAX5965A toc26
MAX5965A toc27
VAGND - VOUT
5V/div
IOUT
1mA/div
(AGND - VOUT)
5V/div
0V
0A
IOUT
1mA/div
VEE
VGATE_
10V/div
0A
VEE
VGATE_
10V/div
40ms/div
______________________________________________________________________________________
11
MAX5965A/MAX5965B
Typical Operating Characteristics (continued)
(VEE = -48V, VDD = +3.3V, VAUTO = VAGND = VDGND = 0V, RESET = SHD_ = unconnected, RSENSE = 0.5Ω, IVEE = 00, ICUT = 000,
TA = +25°C, all registers = default setting, unless otherwise noted.)
MAX5965A/MAX5965B
High-Power, Quad, Monolithic, PSE Controllers
for Power over Ethernet
Typical Operating Characteristics (continued)
(VEE = -48V, VDD = +3.3V, VAUTO = VAGND = VDGND = 0V, RESET = SHD_ = unconnected, RSENSE = 0.5Ω, IVEE = 00, ICUT = 000,
TA = +25°C, all registers = default setting, unless otherwise noted.)
STARTUP WITH DIFFERENT
PD CLASSES
DETECTION WITH INVALID PD (OPEN CIRCUIT,
USING TYPICAL OPERATING CIRCUIT 2)
MAX5965A toc28
MAX5965A toc29
0V
(AGND - VOUT)
5V/div
0A
IOUT
1mA/div
VAGND - VOUT
5V/div
0V
CLASS 5
CLASS 4
CLASS 3
CLASS 2
CLASS 1
VGATE_
10V/div
VEE
IOUT
20mA/div
0A
40ms/div
2-EVENT CLASSIFICATION
WITH A CLASS 4 PD
MAX5965A toc30
VAGND - VOUT
5V/div
0V
IOUT
0A
VEE
20mA/div
VGATE_
10V/div
Pin Description
12
PIN
NAME
FUNCTION
1
RESET
2
MIDSPAN
3
INT
Open-Drain Interrupt Output. INT goes low whenever a fault condition exists. Reset the fault condition
using software or by pulling RESET low (see the Interrupt section for more information about interrupt
management).
4
SCL
Serial Interface Clock Line Input
5
SDAOUT
Hardware Reset. Pull RESET low for at least 300µs to reset the device. All internal registers reset to their
default value. The address (A0–A3), and AUTO and MIDSPAN input-logic levels latch on during low-tohigh transition of RESET. RESET is internally pulled up to VDD with a 50kΩ resistor.
Midspan Mode Input. An internal 50kΩ pulldown resistor to DGND sets the default mode to endpoint PSE
operation (power-over-signal pairs). Pull MIDSPAN to VDIG to set midspan operation. The MIDSPAN value
latches after the device is powered up or reset (see the PD Detection section).
Serial Output Data Line. Connect the data line optocoupler input to SDAOUT (see the Typical Operating
Circuits). Connect SDAOUT to SDAIN if using a 2-wire, I2C-compatible system.
______________________________________________________________________________________
High-Power, Quad, Monolithic, PSE Controllers
for Power over Ethernet
PIN
NAME
FUNCTION
6
SDAIN
Serial Interface Input Data Line. Connect the data line optocoupler output to SDAIN (see the Typical
Operating Circuits). Connect SDAIN to SDAOUT if using a 2-wire, I2C-compatible system.
7–10
A3–A0
Address Bits. A3–A0 form the lower part of the device’s address. Address inputs default high with an
internal 50kΩ pullup resistor to VDD. The address values latch when VDD or VEE ramps up and exceeds
its UVLO threshold or after a reset. The 3 MSBs of the address are set to 010.
11–14
DET1–DET4
15
DGND
16
VDD
17– 20
SHD1–SHD4
21
AGND
22, 25,
29, 32
SENSE4,
SENSE3,
SENSE2,
SENSE1
MOSFET Source Current-Sense Negative Inputs. Connect to the source of the power MOSFET and
connect a current-sense resistor between SENSE_ and VEE (see the Typical Operating Circuits).
23, 26,
30, 33
GATE4,
GATE3,
GATE2,
GATE1
Port_ MOSFET Gate Drivers. Connect GATE_ to the gate of the external MOSFET (see the Typical
Operating Circuits).
24, 27,
31, 34
28
35
36
Detection/Classification Voltage Outputs. Use DET1 to set the detection and classification probe voltages
on port 1. Use DET1 for the AC voltage sensing of port 1 when using the AC disconnect scheme (see the
Typical Operating Circuits).
Digital Ground. Connect to digital ground.
Positive Digital Supply. Connect to a digital power supply (reference to DGND).
Port Shutdown Inputs. Pull SHD_ low to turn off the external FET on port_. Internally pulled up to VDD with
a 50kΩ resistor.
Analog Ground. Connect to the high-side analog supply.
MOSFET Drain-Output Voltage Senses. Connect OUT_ to the power MOSFET drain through a resistor
OUT4, OUT3,
(100Ω to 100kΩ). The low leakage at OUT_ limits the drop across the resistor to less than 100mV (see the
OUT2, OUT1
Typical Operating Circuits).
Low-Side Analog Supply Input. Connect the low-side analog supply to VEE (-48V). Bypass with a 1µF
capacitor between AGND and VEE.
VEE
AUTO
Auto or Shutdown Mode Input. Force AUTO high to enter auto mode after a reset or power-up. Drive low
to put the MAX5965A/MAX5965B into shutdown mode. In shutdown mode, software controls the
operational modes of the MAX5965A/MAX5965B. A 50kΩ internal pulldown resistor defaults to AUTO low.
AUTO latches when VDD or VEE ramps up and exceeds its UVLO threshold or when the device resets.
Software commands can take the MAX5965A/MAX5965B out of AUTO while AUTO is high.
OSC
Oscillator Input. AC-disconnect detection function uses OSC. Connect a 100Hz ±10%, 2VP-P ±5%, +1.3V
offset sine wave to OSC. If the oscillator positive peak falls below the OSC_FAIL threshold of 2V, the ports
that have the AC function enabled shut down and are not allowed to power-up. When not using the ACdisconnect detection function, leave OSC unconnected.
______________________________________________________________________________________
13
MAX5965A/MAX5965B
Pin Description (continued)
MAX5965A/MAX5965B
High-Power, Quad, Monolithic, PSE Controllers
for Power over Ethernet
Functional Diagram
VDD
SCL
SHD_
SDAIN SDAOUT
OSC
DGND
CURRENT SENSING
VOLTAGE PROBING
AND
CURRENT-LIMIT
CONTROL
OSCILLATOR
MONITOR
THREE-WIRE
SERIAL
PORT
INTERFACE
DET_
A0
DETECTION/
CLASSIFICATION
SM
A1
9-BIT ADC
CONVERTER
VOLTAGE
SENSING
OUT_
10V
ACD_ENABLE
PORT
STATE
MACHINE
(SM)
A2
REGISTER FILE
A3
50μA
A=3
GATE_
AUTO
PWR_EN
MIDSPAN
CENTRAL LOGIC UNIT
(CLU)
AC DISCONNECT
SIGNAL
(ACD)
RESET
REGISTER
FILE
INT
DGND
FAST
DISCHARGE
CONTROL
100mA 90μA
MAX
ACD
REFERENCE
CURRENT
CURRENT
MEASUREMENT
VDD
AGND
13V CLAMP
AC
DETECTION*
ANALOG
BIAS/
SUPPLY
MONITOR
+10V ANALOG
SENSE_
9-BIT
ADC
CURRENT
LIMIT (ILIM)
+5V DIG
CURRENT-LIMIT
DETECTOR
VOLTAGE
REFERENCES
VEE
CURRENT
REFERENCES
OPEN CIRCUIT
(OC)
OVERCURRENT
(OVC)
FOLDBACK
CONTROL
MAX5965A/MAX5965B
4mV
182mV
212mV
*AC DETECTION ONLY FOR THE MAX5965B.
14
______________________________________________________________________________________
High-Power, Quad, Monolithic, PSE Controllers
for Power over Ethernet
The MAX5965A/MAX5965B are quad -48V power controllers designed for use in IEEE 802.3af-compliant/preIEEE 802.3at-compatible PSE. The devices provide PD
discovery, classification, current limit, DC and AC load
disconnect detections in compliance with the IEEE 802.3af
standard. The MAX5965A/MAX5965B are pin compatible
with the MAX5952/MAX5945/LTC4258/LTC4259A PSE
controllers and provides additional features.
The MAX5965A/MAX5965B feature a high-power mode,
which provides up to 45W per port. The devices allow
the user to program the current-limit and overcurrent
thresholds up to 2.5 times the default thresholds. The
MAX5965A/MAX5965B can also be programmed to
decrease the current-limit and overcurrent threshold by
15% for high operating voltage conditions to keep the
output power constant.
The MAX5965A/MAX5965B provide new Class 5 and 2event classification (Class 6) for detection and classification of high-power PDs. The MAX5965A/MAX5965B
provide instantaneous readout of each port current
through the I2C interface. The MAX5965A/MAX5965B
also provide high-capacitance detection for legacy PDs.
The MAX5965A/MAX5965B are fully software configurable and programmable through an I2C-compatible,
3-wire serial interface with 49 registers. The class-overcurrent detection function enables system power management to detect if a PD draws more than the
allowable current. The MAX5965A/MAX5965B’s extensive programmability enhances system flexibility,
enables field diagnosis, and allows for uses in other
applications.
The MAX5965A/MAX5965B provide four operating
modes to suit different system requirements. Auto mode
allows the device to operate automatically without any
software supervision. Semi-auto mode automatically
detects and classifies a device connected to a port
after initial software activation but does not power up
that port until instructed to by software. Manual mode
allows total software control of the device and is useful
for system diagnostics. Shutdown mode terminates all
activities and securely turns off power to the ports.
The MAX5965A/MAX5965B provide input undervoltage
lockout, input undervoltage detection, a load-stability
safety check during detection, input overvoltage lockout,
overtemperature detection, output voltage slew-rate limit
during startup, power-good, and fault status. The
MAX5965A/MAX5965B’s programmability includes startup timeout, overcurrent timeout, and load-disconnect
detection timeout.
The MAX5965A/MAX5965B communicate with the system microcontroller through an I2C-compatible interface. The MAX5965A/MAX5965B feature separate input
and output data lines (SDAIN and SDAOUT) for use
with optocoupler isolation. As slave devices, the
MAX5965A/MAX5965B include four address inputs
allowing 16 unique addresses. A separate INT output
and four independent shutdown inputs (SHD_) provide
fast response from a fault to port shutdown between
the MAX5965A/MAX5965B and the microcontroller. A
RESET input allows hardware reset of the device.
Reset
Reset is a condition the MAX5965A/MAX5965B enter
after any of the following conditions:
1) After power-up (V EE and V DD rise above their
UVLO thresholds).
2) Hardware reset. The RESET input is driven low and
back high again any time after power-up.
3) Software reset. Writing a 1 into R1Ah[4] any time
after power-up.
4) Thermal shutdown.
During a reset, the MAX5965A/MAX5965B reset their
register map to the reset state as shown in Table 37
and latch in the state of AUTO (pin 35) and MIDSPAN
(pin 2). During normal operation, change at the AUTO
and MIDSPAN input is ignored. While the condition that
caused the reset persists (i.e. high temperature, RESET
input low, or UVLO conditions) the MAX5965A/
MAX5965B do not acknowledge any addressing from
the serial interface.
Port Reset (R1Ah[3:0])
Set high anytime during normal operation to turn off
power and clear the events and status registers of the
corresponding port. Port reset only resets the events
and status registers.
Midspan Mode
In midspan mode, the device adopts cadence timing
during the detection phase. When cadence timing is
enabled and a failed detection occurs, the port waits
between 2s and 2.4s before attempting to detect again.
Midspan mode is activated by setting R11h[1] high.
The status of the MIDSPAN pin is written to R11h[1]
during power-up or after a reset. MIDSPAN is internally
pulled low by a 50kΩ resistor.
______________________________________________________________________________________
15
MAX5965A/MAX5965B
Detailed Description
MAX5965A/MAX5965B
High-Power, Quad, Monolithic, PSE Controllers
for Power over Ethernet
Operation Modes
The MAX5965A/MAX5965B contain four independent,
but identical state machines to provide reliable and realtime control of the four network ports. Each state
machine has four operating modes: auto mode, semiauto mode, manual, and shutdown. Auto mode allows
the device to operate automatically without any software
supervision. Semi-auto mode, upon request, continuously detects and classifies a device connected to a port
but does not power up that port until instructed by software. Manual mode allows total software control of the
device and is useful in system diagnostics. Shutdown
mode terminates all activities and securely turns off
power to the ports.
Switching between auto, semi, or manual mode does
not interfere with the operation of the port. When the
port is set into shutdown mode, all the port operations
are immediately stopped and the port remains idle until
shutdown is exited.
Automatic (Auto) Mode
Enter automatic (auto) mode by forcing the AUTO input
high prior to a reset, or by setting R12h[P_M1,P_M0] to
[1,1] during normal operation (see Tables 16a and
16b). In auto mode, the MAX5965A/MAX5965B performs detection, classification, and power up the port
automatically once a valid PD is detected at the port. If
a valid PD is not connected at the port, the
MAX5965A/MAX5965B repeat the detection routine
continuously until a valid PD is connected.
Going into auto mode, the DET_EN_ and CLASS_EN_
bits are set to high and stay high unless changed by
software. Using software to set DET_EN_ and/or
CLASS_EN_ low causes the MAX5965A/MAX5965B to
skip detection and/or classification. As a protection, disabling the detection routine in auto mode does not allow
the corresponding port to power up, unless the DET_BY
(R23h[4]) is set to 1.
The AUTO status is latched into the register only during a reset. Any changes to the AUTO input after reset
are ignored.
Semi-Automatic (Semi-Auto) Mode
Enter semi-auto mode by setting R12h[P_M1,P_M0] to
[1,0] during normal operation (see Tables 16a and
16b). In semi-auto mode, the MAX5965A/MAX5965B,
upon request, perform detection and/or classification
repeatedly but do not power up the port(s), regardless
of the status of the port connection.
Setting R19h[PWR_ON_] (Table 22) high immediately
terminates detection/classification routines and turns on
power to the port(s).
16
R14h[DET_EN_, CLASS_EN_] default to low in semi-auto
mode. Use software to set R14h[DET_EN_, CLASS_EN_]
to high to start the detection and/or classification routines. R14h[DET_EN_, CLASS_EN_] are reset every time
the software commands a power off of the port (either
through reset or PWR_OFF_). In any other case, the status of the bits is left unchanged (including when the state
machine turns off the power because a load disconnect
or a fault condition is encountered).
Manual Mode
Enter manual mode by setting R12h[P_M1,P_M0] to [0,1]
during normal operation (see Tables 16a and 16b).
Manual mode allows the software to dictate any
sequence of operation. Write a 1 to both R14h[DET_EN_]
and R14h[CLASS_EN_] to start detection and classification operations, respectively, and in that priority order.
After execution, the command is cleared from the register(s). PWR_ON_ has highest priority. Setting PWR_ON_
high at any time causes the device to immediately enter
the powered mode. Setting DET_EN_ and CLASS_EN_
high at the same time causes detection to be performed
first. Once in the powered state, the device ignores
DET_EN_ or CLASS_EN_ commands.
When switching to manual mode from another mode,
DET_EN_, CLASS_EN_ default to low. These bits
become pushbutton rather than configuration bits (i.e.,
writing ones to these bits while in manual mode commands the device to execute one cycle of detection
and/or classification. The bits are reset back to zeros at
the end of the execution).
Shutdown Mode
Enter shutdown mode by forcing the AUTO input low
prior to a reset, or by setting R12h[P_M1,P_M0] to [0,0]
during normal operation (see Tables 16a and 16b).
Putting the MAX5965A/MAX5965B into shutdown mode
immediately turns off power and halts all operations to
the corresponding port. The event and status bits of the
affected port(s) are also cleared. In shutdown mode, the
DET_EN_, CLASS_EN_, and PWR_ON_ commands are
ignored.
In shutdown mode, the serial interface operates normally.
PD Detection
When PD detection is activated, the MAX5965A/
MAX5965B probe the output for a valid PD. After each
detection cycle, the device sets the DET_END_ bit
R04h/05h[3:0] high and reports the detection results in
the status registers R0Ch[2:0], R0Dh[2:0], R0Eh[2:0],
and R0Fh[2:0]. The DET_END_ bit is reset to low when
read through R05h or after a port reset.
______________________________________________________________________________________
High-Power, Quad, Monolithic, PSE Controllers
for Power over Ethernet
An external diode, in series with the DET_ input, restricts
PD detection to the first quadrant as specified by the
IEEE 802.3af/at standard. To prevent damage to non-PD
devices, and to protect themselves from an output short
circuit, the MAX5965A/MAX5965B limit the current into
DET_ to less than 2mA maximum during PD detection.
In midspan mode, the MAX5965A/MAX5965B wait 2.2s
before attempting another detection cycle after every
failed detection. The first detection, however, happens
immediately after issuing the detection command.
High-Capacitance Detection
The CLC_EN bit in register R23h[5] enables the large
capacitor detection feature for legacy PD devices.
When CLC_EN = 1, the high-capacitance detection limit
is extended up to 150µF. CLC_EN = 0 is the default
condition for the normal capacitor size detection. See
Table 1 and the Register Map and Description section.
Table 1. PSE PI Detection Modes Electrical Requirement
(Table 33-2 of the IEEE 802.3af Standard)
PARAMETER
Open-Circuit Voltage
Short-Circuit Current
SYMBOL
MIN
MAX
UNITS
VOC
—
30
V
In detection mode only
In detection mode only
ISC
—
5
mA
Valid Test Voltage
VVALID
2.8
10
V
Voltage Difference
Between Test Points
ΔVTEST
1
—
V
tBP
2
—
ms
0.1
V/µs
Time Between Any Two
Test Points
Slew Rate
VSLEW
Accept Signature
Resistance
RGOOD
19
26.5
kΩ
Reject Signature
Resistance
RBAD
< 15
> 33
kΩ
Open-Circuit Resistance
ROPEN
500
—
kΩ
Accept Signature
Capacitance
CGOOD
—
150
nF
Reject Signature
Capacitance
CBAD
10
—
µF
Signature Offset Voltage
Tolerance
VOS
0
2.0
V
Signature Offset Current
Tolerance
IOS
0
12
µA
ADDITIONAL INFORMATION
This timing implies a 500Hz maximum probing
frequency
______________________________________________________________________________________
17
MAX5965A/MAX5965B
A valid PD has a 25kΩ discovery signature characteristic
as specified in the IEEE 802.3af/at standard. Table 1
shows the IEEE 802.3af/at specification for a PSE detecting a valid PD signature. See the Typical Operating
Circuits and Figure 1a (Detection, Classification, and
Power-Up Port Sequence). The MAX5965A/MAX5965B
can probe and categorize different types of devices connected to the port such as: a valid PD, an open circuit, a
low resistive load, a high resistive load, a high capacitive
load, a positive DC supply, or a negative DC supply.
During detection, the MAX5965A/MAX5965B keep the
external MOSFET off and force two probe voltages
through the DET_ input. The current through the DET_
input is measured as well as the voltage at OUT_. A
two-point slope measurement is used as specified by
the IEEE 802.3af standard to verify the device connected to the port. The MAX5965A/MAX5965B implement
appropriate settling times and a 100ms digital integration to reject 50Hz/60Hz power-line noise coupling.
MAX5965A/MAX5965B
High-Power, Quad, Monolithic, PSE Controllers
for Power over Ethernet
Powered Device Classification
(PD Classification)
During the PD classification mode, the MAX5965A/
MAX5965B force a probe voltage (-18V) at DET_ and
measure the current into DET_. The measured current
determines the class of the PD.
After each classification cycle, the device sets the
CL_END_ bit (R04h/05h[7:4]) high and reports the classification results in the status registers R0Ch[6:4],
R0Dh[6:4], R0Eh[6:4], and R0Fh[6:4]. The CL_END_ bit
is reset to low when read through register R05h or after
a port reset. Both event registers, R04h, and R05h are
cleared after the port powers down. Table 2 shows the
IEEE 802.3af requirement for a PSE classifying a PD at
the power interface (PI).
The MAX5965A/MAX5965B support high power beyond
the IEEE 802.3af standard by providing additional classifications (Class 5 and 2-event classification).
Class 5 PD Classification
During classification, if the MAX5965A/MAX5965B
detect currents in excess of ICLASS > 48mA, then the
PD will be classified as a Class 5 powered device.
Status registers R0Ch[6:4] or R0Dh[6:4] or R0Eh[6:4] or
R0Fh[6:4] will report the Class 5 classification result.
2-Event (Class 6) PD Classification
When 2-event classification is activated, the classification cycle is repeated three times with 8ms wait time
between each cycle (see Figure 1b). Between each
classification cycle, the MAX5965A/MAX5965B do not
reset the port voltage completely but keeps the output
voltage at -9V. The EN_CL6 bits in R1Ch[7:4] enable 2event classification on a per port basis.
Powered State
When the MAX5965A/MAX5965B enter a powered
state, the tSTART and tDISC timers are reset. Before
turning on the port power, the MAX5965A/MAX5965B
check if any other port is not turning on and if the
tFAULT timer is zero. Another check is performed if the
ACD_EN_ bit is set, in this case the OSC_FAIL bit must
be low (oscillator is okay) for the port to be powered.
If these conditions are met, the MAX5965A/MAX5965B
enter startup where it turns on power to the port. An
internal signal, POK_, asserts high when VOUT_ is within
2V from VEE. PGOOD_ status bits are set high if POK_
stays high longer than tPGOOD. PGOOD_ immediately
resets when POK_ goes low (see Figure 2).
The PG_CHG_ bit sets when a port powers up or down.
PWR_EN_ sets when a port powers up and resets when
a port shuts down. The port shutdown timer lasts 0.5ms
and prevents other ports from turning off during that period, except in the case of emergency shutdowns (RESET
= L, RESET_IC = H, VEEUVLO, VDDUVLO, and TSHD).
The MAX5965A/MAX5965B always check the status of
all ports before turning off. A priority logic system determines the order to prevent the simultaneous turn-on or
turn-off of the ports. The port with the lesser ordinal
number gets priority over the others (i.e., port 1 turns on
first, port 2 second, port 3 third, and port 4 fourth).
Setting PWR_OFF_ high turns off power to the corresponding port.
Table 2. PSE Classification of a PD (Table 33-4 of the IEEE 802.3af)
MEASURED ICLASS (mA)
0 to 5
> 5 and < 8
8 to 13
> 13 and < 16
16 to 21
> 21 and < 25
25 to 31
> 31 and < 35
35 to 45
> 45 and < 51
51 to 68
18
CLASSIFICATION
Class 0
May be Class 0 and 1
Class 1
May be Class 1 or 2
Class 2
May be Class 2 or 3
Class 3
May be Class 3 or 4
Class 4
May be Class 4 or 5
Class 5
______________________________________________________________________________________
High-Power, Quad, Monolithic, PSE Controllers
for Power over Ethernet
150ms
150ms
21.3ms
tDETI
tDETII
tCLASS
MAX5965A/MAX5965B
80ms
0V
t
0V
-4V
-9V
OUT_
-18V
-48V
Figure 1a. Detection, Classification, and Power-Up Port Sequence
80ms
0
150ms
tDETI
150ms
tDETII
21.3ms
21.3ms
21.3ms
tCLASSI
tCLASSII
tCLASSIII
8ms
t
8ms
0V
-4V
-9V
OUT_
-18V
-48V
Figure 1b. Detection, 2-Event Classification, and Power-Up Port Sequence
______________________________________________________________________________________
19
MAX5965A/MAX5965B
High-Power, Quad, Monolithic, PSE Controllers
for Power over Ethernet
POK_
After power-off due to an overcurrent fault, and if the
RSTR_EN bit is set, the tFAULT timer is not immediately
reset but starts decrementing at the same slower pace.
The MAX5965A/MAX5965B allow the port to be powered on only when the tFAULT counter is at zero. This
feature sets an automatic duty-cycle protection to the
external MOSFET avoiding overheating.
The MAX5965A/MAX5965B continuously flag when the
current exceeds the maximum current allowed for the
class as indicated in the CLASS status register. When
class overcurrent occurs, the MAX5965A/MAX5965B
set the IVC_ bit in register R09h.
tPGOOD
PGOOD_
ICUT Register and High-Power Mode
Figure 2. PGOOD_ Timing
Overcurrent Protection
A sense resistor RS connected between SENSE_ and
VEE monitors the load current. Under normal operating
conditions, the voltage across RS (VRS) never exceeds
the threshold V SU_LIM . If V RS exceeds V SU_LIM , an
internal current-limiting circuit regulates the GATE_ voltage, limiting the current to ILIM = VSU_LIM/RS. During
transient conditions, if VRS exceeds VSU_LIM by more
than 1V, a fast pulldown circuit activates to quickly
recover from the current overshoot. During startup, if
the current-limit condition persists, when the startup
timer, t START, times out, the port shuts off, and the
STRT_FLT_ bit is set. In the normal powered state, the
MAX5965A/MAX5965B check for overcurrent conditions as determined by VFLT_LIM = ~88% of VSU_LIM.
The tFAULT counter sets the maximum allowed continuous overcurrent period. The tFAULT counter increases
when VRS exceeds VFLT_LIM and decreases at a slower
pace when VRS drops below VFLT_LIM. A slower decrement for the tFAULT counter allows for detecting repeated short-duration overcurrents. When the counter
reaches the t FAULT limit, the MAX5965A/MAX5965B
power off the port and assert the IMAX_FLT_ bit. For a
continuous overstress, a fault latches exactly after a
period of tFAULT. VSU_LIM is programmable through the
ICUT registers R2Ah[6:4], R2Ah[2:0], R2Bh[6:4],
R2Bh[2:0], and the IVEE bits in register R29h[1:0]. See
the High-Power Mode section for more information on
the ICUT register.
20
ICUT Register
The ICUT register determines the maximum current limits allowed for each port of the MAX5965A/MAX5965B.
The 3 ICUT bits (R2Ah[6:4], R2Ah[2:0], R2Bh[6:4], and
R2Bh[2:0]) allow programming of the current-limit and
overcurrent thresholds in excess of the IEEE standard
limit (see Tables 34a, 34b, and 34c). The ICUT registers can be written to directly through the I2C interface
when CL_DISC (R17h[2]) is set to 0 (see Table 3). In
this case, the current limit of the port is configured
regardless of the status of the classification.
By setting the CL_DISC bit to 1, the MAX5965A/
MAX5965B automatically set the ICUT register based
upon the classification result of the port. See Table 3
and the Register Map and Description section.
High-Power Mode
When CL_DISC (R17h[2]) is set to 0, high-power mode
is configured by setting the ICUT bits to any combination other than 000, 110, or 111 (note that 000 is the
default value for the IEEE standard limit). See Table 3
and the Register Map and Description section.
Foldback Current
During startup and normal operation, an internal circuit
senses the voltage at OUT_ and reduces the currentlimit value when (VOUT_ - VEE) > 28V. The foldback
function helps to reduce the power dissipation on the
FET. The current limit eventually reduces down to 1/3 of
ILIM when (VOUT_ - VEE ) > 48V (see Figure 3a). For
high-power mode, the foldback starts when (VOUT_ VEE ) > 10V (see Figure 3b). In high-power mode, the
current limit (ILIM) is reduced down to minimum foldback current (VTH_FB/RS) when (VOUT_ - VEE ) > 48V.
______________________________________________________________________________________
High-Power, Quad, Monolithic, PSE Controllers
for Power over Ethernet
CL_DISC
PORT
CLASSIFICATION ENx_CL6 EN_HP_ALL EN_HP_CL6 EN_HP_CL5
RESULT
RESULTING ICUT
REGISTER BITS
EN_HP_CL4
0
Any
X
X
X
X
X
User programmed
1
1
X
X
X
X
X
ICUT = 110
1
2
X
X
X
X
X
ICUT = 111
1
0, 3
X
X
X
X
X
ICUT = 000
1
4, 5
X
0
X
X
X
ICUT = 000
1
5
X
1
X
1
X
ICUT = R24h[6:4]
1
5
X
1
X
0
X
ICUT = 000
1
4
X
1
X
x
1
ICUT = R24h[6:4]
1
4
X
1
X
X
0
ICUT = 000
1
6 or Illegal
0
X
X
X
X
—
1
6 or Illegal
1
1
1
X
X
(See Table 35a)
1
6 or Illegal
1
1
0
X
X
ICUT = 000
1
6 or Illegal
1
0
X
X
X
ICUT = 000
MOSFET Gate Driver
Connect the gate of the external n-channel MOSFET to
GATE_. An internal 50µA current source pulls GATE_ to
(VEE + 10V) to turn on the MOSFET. An internal 40µA
current source pulls down GATE_ to VEE to turn off the
MOSFET.
The pullup and pulldown current controls the maximum
slew rate at the output during turn-on or turn-off. Use
the following equation to set the maximum slew rate:
ΔVOUT IGATE
=
Δt
CGD
where CGD is the total capacitance between GATE and
DRAIN of the external MOSFET. Current limit and the
capacitive load at the drain control the slew rate during
startup. During current-limit regulation, the
MAX5965A/MAX5965B manipulate the GATE_ voltage
to control the voltage at SENSE_ (VRS). A fast pulldown
activates if V RS overshoots the limit threshold
(VSU_LIM). The fast pulldown current increases with the
amount of overshoot. The maximum fast pulldown current is 100mA.
During turn-off, when the GATE_ voltage reaches a
value lower than 1.2V, a strong pulldown switch is activated to keep the MOSFET securely off.
(VRS - VEE)
(VRS - VEE)
VSU_LIM
VSU_LIM
VSU_LIM / 3
VTH_FB
28V
Figure 3a. Foldback Current Characteristics
48V
(VOUT_ - VEE)
MAX5965A/MAX5965B
Table 3. Automatic ICUT Programming
10V
48V
(VOUT_ - VEE)
Figure 3b. Foldback Current Characteristics for High-Power Mode
______________________________________________________________________________________
21
MAX5965A/MAX5965B
High-Power, Quad, Monolithic, PSE Controllers
for Power over Ethernet
Digital Logic
VDD supplies power for the internal logic circuitry. VDD
ranges from +3.0V to +5.5V and determines the logic
thresholds for the CMOS connections (SDAIN, SDAOUT,
SCL, AUTO, SHD_, A_). This voltage range enables the
MAX5965A/MAX5965B to interface with a nonisolated
low-voltage microcontroller. The MAX5965A/MAX5965B
check the digital supply for compatibility with the internal
logic. The MAX5965A/MAX5965B also feature a VDD
undervoltage lockout (VDDUVLO) of +2.0V. A VDDUVLO
condition keeps the MAX5965A/MAX5965B in reset and
the ports shut off. Bit 0 in the supply event register shows
the status of VDDUVLO (Table 12) after VDD has recovered. All logic inputs and outputs reference to DGND.
For AC-disconnected detection, DGND and AGND must
be connected together externally. Connect DGND to
AGND at a single point in the system as close as possible to the MAX5965A/MAX5965B.
Hardware Shutdown
SHD_ shuts down the respective ports without using the
serial interface. Hardware shutdown offers an emergency turn-off feature that allows a fast disconnect of
the power supply from the port. Pull SHD_ low to
remove power. SHD_ also resets the corresponding
events and status register bits.
Interrupt
The MAX5965A/MAX5965B contain an open-drain logic
output (INT) that goes low when an interrupt condition
exists. R00h and R01h (Tables 6 and 7) contain the definitions of the interrupt registers. The mask register R01h
determines events that trigger an interrupt. As a response
to an interrupt, the controller reads the status of the event
register to determine the cause of the interrupt and takes
subsequent actions. Each interrupt event register also
contains a Clear on Read (CoR) register. Reading
through the CoR register address clears the interrupt. INT
remains low when reading the interrupt through the readonly addresses. For example, to clear a startup fault on
the port 4 read address 09h (see Table 11). Use the global pushbutton bit in register 1Ah (bit 7, Table 23) to clear
interrupts, or use a software or hardware reset.
Undervoltage and
Overvoltage Protection
The MAX5965A/MAX5965B contain several undervoltage
and overvoltage protection features. Table 12 in the
Register Map and Description section shows a detailed
list of the undervoltage and overvoltage protection features. An internal VEE undervoltage lockout (VEEUVLO) circuit keeps the MOSFET off and the MAX5965A/
MAX5965B in reset until VAGND - VEE exceeds 29V for
more than 3ms. An internal VEE overvoltage (VEE_OV) circuit shuts down the ports when (VAGND - VEE) exceeds
22
60V. The digital supply also contains an undervoltage
lockout (VDDUVLO). The MAX5965A/MAX5965B also feature three other undervoltage and overvoltage interrupts:
VEE undervoltage interrupt (VEEUV), VDD undervoltage
interrupt (V DDUV ), and V DD overvoltage interrupt
(VDDOV). A fault latches into the supply events register
(Table 12), but the MAX5965A/MAX5965B does not shut
down the ports with VEEUV, VDDUV, or VDDOV.
DC Disconnect Monitoring
Setting R13h[DCD_EN_] bits high enables DC load monitoring during a normal powered state. If VRS (the voltage
across RS) falls below the DC load disconnect threshold,
VDCTH, for more than tDISC, the device turns off power
and asserts the LD_DISC_ bit of the corresponding port.
AC Disconnect Monitoring
(MAX5965A/MAX5965B)
The MAX5965A/MAX5965B feature AC load disconnect
monitoring. Connect an external sine wave to OSC. The
oscillator requirements are:
1) VP-P x Frequency = 200VP-P x Hz ±15%
2) Positive peak voltage > +2.2V
3) Frequency > 60Hz
A 100Hz ±10%, 2VP-P ±5%, with +1.3V offset (VPEAK =
+2.3V typical) is recommended.
The MAX5965A/MAX5965B buffer and amplify three
times the external oscillator signal and sends the signal
to DET_, where the sine wave is AC-coupled to the output. The MAX5965A/MAX5965B sense the presence of
the load by monitoring the amplitude of the AC current
returned to DET_ (see the Functional Diagram).
Setting R13h[ACD_EN_] bits high enable AC load disconnect monitoring during a normal powered state. If
the AC current peak at the DET_ input falls below IACTH
for more than tDISC, the device turns off power and
asserts the LD_DISC_ bit of the corresponding port.
IACTH is programmable using R23h[2:0].
An internal comparator checks for a proper amplitude of
the oscillator input. If the positive peak of the input sinusoid falls below a safety value of 2V (typ), OSC_FAIL
sets and the port shuts down. Power cannot be applied
to the ports when ACD_EN_ is set high and OSC_FAIL
is set high. Leave OSC unconnected or connect it to
DGND when not using AC-disconnect detection.
Thermal Shutdown
If the MAX5965A/MAX5965B die temperature reaches
+150°C, an overtemperature fault generates and the
MAX5965A/MAX5965B shut down. The MOSFETs turn off.
The die temperature of the MAX5965A/MAX5965B must
cool down below +130°C to remove the overtemperature
fault condition. After a thermal shutdown, the part is reset.
______________________________________________________________________________________
High-Power, Quad, Monolithic, PSE Controllers
for Power over Ethernet
I2C-Compatible Serial Interface
The MAX5965A/MAX5965B operate as a slave that
sends and receives data through an I2C-compatible, 2wire or 3-wire interface. The interface uses a serial-data
input line (SDAIN), a serial-data output line (SDAOUT),
and a serial-clock line (SCL) to achieve bidirectional
communication between master(s) and slave(s). A master (typically a microcontroller) initiates all data transfers
to and from the MAX5965A/MAX5965B, and generates
the SCL clock that synchronizes the data transfer. In
most applications, connect the SDAIN and the SDAOUT
lines together to form the serial-data line (SDA).
Using the separate input and output data lines allows
optocoupling with the controller bus when an isolated
supply powers the microcontroller.
Address Inputs
A3, A2, A1, and A0 represent the 4 LSBs of the chip
address. The complete chip address is 7 bits (see
Table 4).
The 4 LSBs latch on the low-to-high transition of RESET or
after a power-supply start (either on VDD or VEE). Address
inputs default high through an internal 50kΩ pullup resistor
to VDD. The MAX5965A/MAX5965B also respond to the
call through a global address 30h (see the Global
Addressing and Alert Response Protocol section).
The MAX5965A/MAX5965B SDAIN line operates as an
input. The MAX5965A/MAX5965B SDAOUT operates as
an open-drain output. A pullup resistor, typically 4.7kΩ,
is required on SDAOUT. The MAX5965A/MAX5965B SCL
line operates only as an input. A pullup resistor, typically
4.7kΩ, is required on SCL if there are multiple masters,
or if the master in a single-master system has an opendrain SCL output.
Table 4. MAX5965A/MAX5965B Address
0
1
0
A3
A2
A1
A0
R/W
SDAIN
tBUF
tSU, DAT
tLOW
tSU, STA
tHD, DAT
tHD, STA
tSU, STO
SCL
tHIGH
tHD, STA
tR
tF
START CONDITION
REPEATED START CONDITION
STOP
CONDITION
START
CONDITION
Figure 4. 2-Wire, Serial-Interface Timing Details
SDAIN/SDA
tBUF
tSU, DAT
tLOW
tSU, STA
tHD, DAT
tHD, STA
tSU, STO
SCL
tHIGH
tHD, STA
tR
tF
START CONDITION
REPEATED START CONDITION
STOP
CONDITION
START
CONDITION
Figure 5. 3-Wire, Serial-Interface Timing Details
______________________________________________________________________________________
23
MAX5965A/MAX5965B
Watchdog
The R1Eh and R1Fh registers control the watchdog
operation. The watchdog function, when enabled, allows
the MAX5965A/MAX5965B to gracefully take over control or securely shuts down the power to the ports in
case of software/firmware crashes. Contact the factory
for more details.
MAX5965A/MAX5965B
High-Power, Quad, Monolithic, PSE Controllers
for Power over Ethernet
Serial Addressing
Each transmission consists of a START condition (Figure
6) sent by a master, followed by the MAX5965A/
MAX5965B 7-bit slave address plus R/W bit, a register
address byte, one or more data bytes, and finally a
STOP condition.
Bit Transfer
Each clock pulse transfers one data bit (Figure 7). The
data on SDA must remain stable while SCL is high.
Acknowledge
The acknowledge bit is a clocked 9th bit (Figure 8) that
the recipient uses to handshake receipt of each byte of
data. Thus each byte effectively transferred requires 9
bits. The master generates the 9th clock pulse, and the
recipient pulls down SDA (or the SDAOUT in the 3-wire
interface) during the acknowledge clock pulse, so that
the SDA line is stable low during the high period of the
clock pulse. When the master transmits to the
MAX5965A/MAX5965B, the MAX5965A/MAX5965B
generate the acknowledge bit. When the MAX5965A/
MAX5965B transmit to the master, the master generates the acknowledge bit.
START and STOP Conditions
Both SCL and SDA remain high when the interface is
not busy. A master signals the beginning of a transmission with a START (S) condition by transitioning SDA
from high to low while SCL is high. When the master finishes communicating with the slave, the master issues
a STOP (P) condition by transitioning SDA from low to
high while SCL is high. The STOP condition frees the
bus for another transmission.
SDA
SDA/
SDAIN
SCL
SCL
S
START
P
STOP
.
DATA LINE STABLE; CHANGE OF
DATA VALID
DATA ALLOWED
Figure 7. Bit Transfer
Figure 6. START and STOP Conditions
CLOCK PULSE FOR ACKNOWLEDGEMENT
START CONDITION
1
SCL
2
8
9
SDA
BY TRANSMITTER
S
SDA
BY RECEIVER
Figure 8. Acknowledge
24
______________________________________________________________________________________
High-Power, Quad, Monolithic, PSE Controllers
for Power over Ethernet
is delivering. If it is not, it then backs off and frees the
data line. This litigation protocol always allows the part
with the lowest address to complete the transmission.
The microcontroller can then respond to the interrupt
and take proper actions. The MAX5965A/MAX5965B do
not reset their own interrupt at the end of the alert
response protocol. The microcontroller has to do it by
clearing the event register through their CoR adresses
or activating the CLR_INT pushbutton.
Message Format for Writing to the
MAX5965A/MAX5965B
A write to the MAX5965A/MAX5965B comprises of the
MAX5965A/MAX5965B’s slave address transmission
with the R/W bit set to 0, followed by at least 1 byte of
information. The first byte of information is the command byte (Figure 10). The command byte determines
which register of the MAX5965A/MAX5965B is written to
by the next byte, if received. If the MAX5965A/
MAX5965B detect a STOP condition after receiving the
command byte, the MAX5965A/MAX5965B take no further action beyond storing the command byte. Any
bytes received after the command byte are data bytes.
The first data byte goes into the internal register of the
MAX5965A/MAX5965B selected by the command byte.
If the MAX5965A/MAX5965B transmit multiple data
bytes before the MAX5965A/MAX5965B detect a STOP
condition, these bytes store in subsequent MAX5965A/
MAX5965B internal registers because the control byte
address autoincrements.
Global Addressing and Alert Response Protocol
The global address call is used in writing mode to write
the same register to multiple devices (address 0x60). In
read mode (address 0x61), the global address call is
used as the alert response address. When responding
to a global call, the MAX5965A/MAX5965B put their
own address out on the data line whenever the interrupt
is active. Every other device connected to the SDAOUT
line that has an active interrupt also does this. After
every bit transmitted, the MAX5965A/MAX5965B check
that the data line effectively corresponds to the data it
MSB
SDAIN/SDA
0
LSB
1
0
A3
A2
A1
A0
R/W
ACK
SCL
Figure 9. Slave Address
CONTROL BYTE IS STORED ON RECEIPT OF STOP CONDITION
ACKNOWLEDGE FROM THE MAX5965A/MAX5965B
S
SLAVE ADDRESS
0
R/W
D15
A
D14
D13
D12
D11
D10
D9
D8
CONTROL BYTE
A
P
ACKNOWLEDGE FROM THE MAX5965A/MAX5965B
Figure 10. Control Byte Received
______________________________________________________________________________________
25
MAX5965A/MAX5965B
Slave Address
The MAX5965A/MAX5965B have a 7-bit long slave
address (Figure 9). The bit following the 7-bit slave
address (bit eight) is the R/W bit, which is low for a
write command and high for a read command.
010 always represents the first 3 bits (MSBs) of the
MAX5965A/MAX5965B slave address. Slave address
bits A3, A2, A1, and A0 represent the states of the
MAX5965A/MAX5965B’s A3, A2, A1, and A0 inputs,
allowing up to sixteen MAX5965A/MAX5965B devices
to share the bus. The states of the A3, A2, A1, and A0
latch in upon the reset of the MAX5965A/MAX5965B
into register R11h. The MAX5965A/MAX5965B monitor
the bus continuously, waiting for a START condition followed by the MAX5965A/MAX5965B’s slave address.
When a MAX5965A/MAX5965B recognizes its slave
address, the MAX5965A/MAX5965B acknowledge and
are then ready for continued communication.
MAX5965A/MAX5965B
High-Power, Quad, Monolithic, PSE Controllers
for Power over Ethernet
Message Format for Reading
The MAX5965A/MAX5965B read using the MAX5965A/
MAX5965B’s internally stored command byte as an
address pointer, the same way the stored command
byte is used as an address pointer for a write. The pointer autoincrements after reading each data byte using the
same rules as for a write. Thus, a read is initiated by first
configuring the MAX5965A/MAX5965B’s command byte
by performing a write. The master now reads ‘n’ consecutive bytes from the MAX5965A/MAX5965B, with the first
data byte read from the register addressed by the initialized command byte. When performing read-after-write
verification, remember to reset the command byte’s
address because the stored control byte address autoincrements after the write.
Operation with Multiple Masters
When the MAX5965A/MAX5965B operate on a 2-wire
interface with multiple masters, a master reading the
MAX5965A/MAX5965B should use repeated starts
between the write which sets the MAX5965A/
MAX5965B’s address pointer, and the read(s) that take
the data from the location(s). It is possible for master 2 to
take over the bus after master 1 has set up the
MAX5965A/MAX5965B’s address pointer but before master 1 has read the data. If master 2 subsequently resets
the MAX5965A/MAX5965B’s address pointer then master
1’s read may be from an unexpected location.
Command Address Autoincrementing
Address autoincrementing allows the MAX5965A/
MAX5965B to be configured with fewer transmissions
by minimizing the number of times the command
address needs to be sent. The command address
stored in the MAX5965A/MAX5965B generally increments after each data byte is written or read (Table 5).
The MAX5965A/MAX5965B are designed to prevent
overwrites on unavailable register addresses and unintentional wrap-around of addresses.
Table 5. Autoincrement Rules
COMMAND BYTE
ADDRESS RANGE
0x00 to 0x26
Command address autoincrements
after byte read or written
0x26
Command address remains at 0x26
after byte written or read
ACKNOWLEDGE FROM THE MAX5965A/MAX5965B
HOW CONTROL BYTE AND DATA BYTE MAP
INTO THE REGISTER
ACKNOWLEDGE FROM THE MAX5965A/MAX5965B
S
SLAVE ADDRESS
0
D15 D14 D13 D12 D11 D10
A
AUTOINCREMENT BEHAVIOR
D9
ACKNOWLEDGE FROM THE MAX5965A/MAX5965B
D8
CONTROL BYTE
D7
D6
D5
A
D4
D3
D2
D1
D0
DATA BYTE
A
P
1 BYTE
R/W
AUTOINCREMENT
MEMORY WORD ADDRESS
Figure 11. Control and Single Data Byte Received
ACKNOWLEDGE FROM THE MAX5965A/MAX5965B
HOW CONTROL BYTE AND DATA BYTE MAP
INTO THE REGISTER
ACKNOWLEDGE FROM THE MAX5965A/MAX5965B
S
SLAVE ADDRESS
0
R/W
D15 D14 D13 D12 D11 D10
A
CONTROL BYTE
D9
ACKNOWLEDGE FROM THE MAX5965A/MAX5965B
D8
D7
A
D6
D5
D4
D3
D2
DATA BYTE
D1
D0
A
P
n BYTES
AUTOINCREMENT
MEMORY WORD ADDRESS
Figure 12. ‘n’ Data Bytes Received
26
______________________________________________________________________________________
High-Power, Quad, Monolithic, PSE Controllers
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The interrupt register (Table 6) summarizes the event
register status and is used to send an interrupt signal
(INT goes low) to the controller. Writing a 1 to R1Ah[7]
clears all interrupt and events registers. A reset sets
R00h to 00h.
INT_EN (R17h[7]) is a global interrupt mask (Table 7).
The MASK_ bits activate the corresponding interrupt
bits in register R00h. Writing a 0 to INT_EN (R17h[7])
disables the INT output.
A reset sets R01h to AAA00A00b where A is the state of
the AUTO input prior to the reset.
Table 6. Interrupt Register
ADDRESS = 00h
SYMBOL
DESCRIPTION
BIT
R/W
SUP_FLT
7
R
Interrupt signal for supply faults. SUP_FLT is the logic OR of all the bits [7:0] in register
R0Ah/R0Bh (Table 12).
TSTR_FLT
6
R
Interrupt signal for startup failures. TSTR_FLT is the logic OR of bits [7:0] in register
R08h/R09h (Table 11).
IMAX_FLT
5
R
Interrupt signal for current-limit violations. IMAX_FLT is the logic OR of bits [3:0] in register
R06h/R07h (Table 10).
CL_END
4
R
Interrupt signal for completion of classification. CL_END is the logic OR of bits [7:4] in
register R04h/R05h (Table 9).
DET_END
3
R
Interrupt signal for completion of detection. DET_END is the logic OR of bits [3:0] in
register R04h/R05h (Table 9).
LD_DISC
2
R
Interrupt signal for load disconnection. LD_DISC is the logic OR of bits [7:4] in register
R06h/R07h (Table 10).
PG_INT
1
R
Interrupt signal for PGOOD status change. PG_INT is the logic OR of bits [7:4] in register
R02h/R03h (Table 8).
PEN_INT
0
R
Interrupt signal for power-enable status change. PEN_INT is the logic OR of bits [3:0] in
register R02h/R03h (Table 8).
Table 7. Interrupt Mask Register
ADDRESS = 01h
SYMBOL
DESCRIPTION
BIT
R/W
MASK7
7
R/W
Interrupt mask bit 7. A logic-high enables the SUP_FLT interrupts. A logic-low disables the
SUP_FLT interrupts.
MASK6
6
R/W
Interrupt mask bit 6. A logic-high enables the TSTR_FLT interrupts. A logic-low disables
the TSTR_FLT interrupts.
MASK5
5
R/W
Interrupt mask bit 5. A logic-high enables the IMAX_FLT interrupts. A logic-low disables
the IMAX_FLT interrupts.
MASK4
4
R/W
Interrupt mask bit 4. A logic-high enables the CL_END interrupts. A logic-low disables the
CL_END interrupts.
MASK3
3
R/W
Interrupt mask bit 3. A logic-high enables the DET_END interrupts. A logic-low disables the
DET_END interrupts.
MASK2
2
R/W
Interrupt mask bit 2. A logic-high enables the LD_DISC interrupts. A logic-low disables the
LD_DISC interrupts.
MASK1
1
R/W
Interrupt mask bit 1. A logic-high enables the PG_INT interrupts. A logic-low disables the
PG_INT interrupts.
MASK0
0
R/W
Interrupt mask bit 0. A logic-high enables the PEN_INT interrupts. A logic-low disables the
PEN_INT interrupts.
______________________________________________________________________________________
27
MAX5965A/MAX5965B
Register Map and Description
MAX5965A/MAX5965B
High-Power, Quad, Monolithic, PSE Controllers
for Power over Ethernet
The power event register (Table 8) records changes in
the power status of the four ports. Any change in
PGOOD_ (R10h[7:4]) sets PG_CHG_ to 1. Any change
in the PWR_EN_ (R10h[3:0]) sets PWEN_CHG_ to 1.
PG_CHG_ and PWEN_CHG_ trigger on the edges of
PGOOD_ and PWR_EN_ and do not depend on the
actual level of the bits. The power event register has
two addresses. When read through the R02h address,
the content of the register is left unchanged. When read
through the CoR R03h address, the register content is
cleared. A reset sets R02h/R03h = 00h.
Table 8. Power Event Register
ADDRESS
SYMBOL
BIT
02h
03h
R/W
R/W
DESCRIPTION
PG_CHG4
7
R
CoR
PGOOD change event for port 4
PG_CHG3
6
R
CoR
PGOOD change event for port 3
PG_CHG2
5
R
CoR
PGOOD change event for port 2
PG_CHG1
4
R
CoR
PGOOD change event for port 1
PWEN_CHG4
3
R
CoR
Power enable change event for port 4
PWEN_CHG3
2
R
CoR
Power enable change event for port 3
PWEN_CHG2
1
R
CoR
Power enable change event for port 2
PWEN_CHG1
0
R
CoR
Power enable change event for port 1
DET_END_/CL_END_ is set high whenever detection/
classification is completed on the corresponding port. A
1 in any of the CL_END_ bits forces R00h[4] to 1. A 1 in
any of the DET_END_ bits forces R00h[3] to 1. As with
any of the other events register, the detect event register
has two addresses. When read through the R04h
address, the content of the register is left unchanged.
When read through the CoR R05h address, the register
content is cleared. A reset sets R04h/R05h = 00h.
Table 9. Detect Event Register
ADDRESS
SYMBOL
BIT
04h
05h
DESCRIPTION
R/W
R/W
CL_END4
7
R
CoR
Classification completed on port 4
CL_END3
6
R
CoR
Classification completed on port 3
CL_END2
5
R
CoR
Classification completed on port 2
CL_END1
4
R
CoR
Classification completed on port 1
DET_END4
3
R
CoR
Detection completed on port 4
DET_END3
2
R
CoR
Detection completed on port 3
DET_END2
1
R
CoR
Detection completed on port 2
DET_END1
0
R
CoR
Detection completed on port 1
28
______________________________________________________________________________________
High-Power, Quad, Monolithic, PSE Controllers
for Power over Ethernet
As with any of the other events register, the fault event
register has two addresses. When read through the
R06h address, the content of the register is left
unchanged. When read through the CoR R07h
address, the register content is cleared. A reset sets
R06h/R07h = 00h.
Table 10. Fault Event Register
ADDRESS
SYMBOL
BIT
06h
07h
R/W
R/W
DESCRIPTION
LD_DISC4
7
R
CoR
Disconnect on port 4
LD_DISC3
6
R
CoR
Disconnect on port 3
LD_DISC2
5
R
CoR
Disconnect on port 2
LD_DISC1
4
R
CoR
Disconnect on port 1
IMAX_FLT4
3
R
CoR
Overcurrent on port 4
IMAX_FLT3
2
R
CoR
Overcurrent on port 3
IMAX_FLT2
1
R
CoR
Overcurrent on port 2
IMAX_FLT1
0
R
CoR
Overcurrent on port 1
If the port remains in current limit or the PGOOD condition is not met at the end of the startup period, the port
shuts down and the corresponding STRT_FLT_ is set to
1. A 1 in any of the STRT_FLT_ bits forces R00h[6] to 1.
IVC_ is set to 1 whenever the port current exceeds the
maximum allowed limit for the class (determined during
the classification process). A 1 in any of IVC_ forces
R00h[6] to 1. When the CL_DISC (R17h[2]) is set to 1,
the port also limits the load current according to its
class as specified in the Electrical Characteristics table.
As with any of the other events register, the startup
event register has two addresses. When read through
the R08h address, the content of the register is left
unchanged. When read through the CoR R09h
address, the register content is cleared. A reset sets
R08h/R09h = 00h.
Table 11. Startup Event Register
ADDRESS
SYMBOL
BIT
08h
09h
R/W
R/W
DESCRIPTION
IVC4
7
R
CoR
Class overcurrent flag for port 4
IVC3
6
R
CoR
Class overcurrent flag for port 3
IVC2
5
R
CoR
Class overcurrent flag for port 2
IVC1
4
R
CoR
Class overcurrent flag for port 1
STRT_FLT4
3
R
CoR
Startup failed on port 4
STRT_FLT3
2
R
CoR
Startup failed on port 3
STRT_FLT2
1
R
CoR
Startup failed on port 2
STRT_FLT1
0
R
CoR
Startup failed on port 1
______________________________________________________________________________________
29
MAX5965A/MAX5965B
LD_DISC_ is set high whenever the corresponding port
shuts down due to detection of load removal.
IMAX_FLT_ is set high when the port shuts down due to
an extended overcurrent event after a successful startup. A 1 in any of the LD_DISC_ bits forces R00h[2] to 1.
A 1 in any of the IMAX_FLT_ bits forces R00h[5] to 1.
MAX5965A/MAX5965B
High-Power, Quad, Monolithic, PSE Controllers
for Power over Ethernet
The MAX5965A/MAX5965B continuously monitor the
power supplies and set the appropriate bits in the supply event register (Table 12). VDD_OV/VEE_OV is set to 1
whenever VDD/VEE exceeds its overvoltage threshold.
V DD_UV /V EE_UV is set to 1 whenever V DD /V EE falls
below its undervoltage threshold.
OSC_FAIL is set to 1 whenever the amplitude of the
oscillator signal at the OSC input falls below a level that
might compromise the AC disconnect detection function. OSC_FAIL generates an interrupt only if at least
one of the ACD_EN (R13h[7:4]) bits is set high.
A thermal shutdown circuit monitors the temperature of
the die and resets the MAX5965A/MAX5965B if the
temperature exceeds +150°C. TSD is set to 1 after the
MAX5965A/MAX5965B return to normal operation. TSD
is also set to 1 after every UVLO reset.
When VDD and/or |VEE| is below its UVLO threshold, the
MAX5965A/MAX5965B are in reset mode and securely
holds all ports off. When VDD and |VEE| rise to above
their respective UVLO thresholds, the device comes out
of reset as soon as the last supply crosses the UVLO
threshold. The last supply corresponding UV and UVLO
bits in the supply event register is set to 1.
A 1 in any supply event register’s bits forces R00h[7] to
1. As with any of the other events register, the supply
event register has two addresses. When read through
the R0Ah address, the content of the register is left
unchanged. When read through the CoR R0Bh
address, the register content is cleared. A reset sets
R0Ah/R0Bh to 00100001b if VDD comes up after VEE or
to 00010100b if VEE comes up after VDD.
Table 12. Supply Event Register
ADDRESS
SYMBOL
BIT
0Ah
0Bh
R/W
R/W
DESCRIPTION
TSD
7
R
CoR
Overtemperature shutdown
VDD_OV
6
R
CoR
VDD overvoltage condition
VDD_UV
5
R
CoR
VDD undervoltage condition
VEE_UVLO
4
R
CoR
VEE undervoltage lockout condition
VEE_OV
3
R
CoR
VEE overvoltage condition
VEE_UV
2
R
CoR
VEE undervoltage condition
OSC_FAIL
1
R
CoR
Oscillator amplitude is below limit
VDD_UVLO
0
R
CoR
VDD undervoltage lockout condition
30
______________________________________________________________________________________
High-Power, Quad, Monolithic, PSE Controllers
for Power over Ethernet
When 2-event classification is not enabled (ENx_CL6 =
0), the classification status is reported in Table 13c.
When 2-event classification is enabled (ENx_CL6 = 1),
the CLASS_[2:0] bits are set to 000 and the classification result is reported in locations R2Ch–R2Fh.
As a protection, when POFF_CL (R17h[3], Table 21) is
set to 1, the MAX5965A/MAX5965B prohibit turning on
power to the port that returns a status 111 after classification. A reset sets 0Ch, 0Dh, 0Eh, and 0Fh = 00h.
Table 13a. Port Status Registers
ADDRESS = 0Ch, 0Dh, 0Eh, 0Fh
SYMBOL
Reserved
CLASS_
Reserved
DET_ST_
DESCRIPTION
BIT
R/W
7
R
Reserved
6
R
CLASS_[2]
5
R
CLASS_[1]
4
R
CLASS_[0]
3
R
Reserved
2
R
DET_ST_[2]
1
R
DET_ST_[1]
0
R
DET_ST_[0]
Table 13b. Detection Result Decoding Chart
DET_ST_[2:0]
(ADDRESS = 0Ch, 0Dh, 0Eh, 0Fh)
DETECTED
DESCRIPTION
000
None
Detection status unknown
001
DCP
Positive DC supply connected at the port (AGND - VOUT_ < 1V)
010
HIGH CAP
High capacitance at the port (> 8.5µF)
011
RLOW
Low resistance at the port, RPD < 15kΩ
100
DET_OK
Detection pass, 15kΩ < RPD < 33kΩ
101
RHIGH
High resistance at the port, RPD > 33kΩ
110
OPEN0
Open port (I < 10µA)
111
DCN
Negative DC supply connected to the port (VOUT_ - VEE < 2V)
Table 13c. Classification Result Decoding
Chart
CLASS_[2:0]
(ADDRESS = 0Ch, 0Dh, 0Eh, 0Fh)
CLASS RESULT
000
Unknown
001
1
010
2
011
3
100
4
101
5
110
0
111
Current limit (> ICILIM)
______________________________________________________________________________________
31
MAX5965A/MAX5965B
The port status register (Table 13a) records the results of
the detection and classification at the end of each phase in
three encoding bits each. R0Ch contains the detection
and classification status of port 1. R0Dh corresponds to
port 2, R0Eh corresponds to port 3, and R0Fh corresponds
to port 4. Tables 13b and 13c show the detection/classification result decoding charts, respectively. For CLC_EN =
0, the detection result is shown in Table 13b. When
CLC_EN is set high, the MAX5965A/MAX5965B allow valid
detection of high capacitive load of up to 150µF.
MAX5965A/MAX5965B
High-Power, Quad, Monolithic, PSE Controllers
for Power over Ethernet
PGOOD_ is set to 1 (Table 14) at the end of the powerup startup period if the power-good condition is met (0
< (VOUT_ - VEE) < PGTH). The power-good condition
must remain valid for more than t PGOOD to assert
PGOOD_. PGOOD_ is reset to 0 whenever the output
falls out of the power-good condition. A fault condition
immediately forces PGOOD_ low.
PWR_EN_ is set to 1 when the port power is turned on.
PWR_EN_ resets to 0 as soon as the port turns off. Any
transition of PGOOD_ and PWR_EN_ bits set the corresponding bit in the power event registers R02h/R03h
(Table 8). A reset sets R10h = 00h.
Table 14. Power Status Register
ADDRESS = 10h
SYMBOL
DESCRIPTION
BIT
R/W
PGOOD4
7
R
Power-good condition on port 4
PGOOD3
6
R
Power-good condition on port 3
PGOOD2
5
R
Power-good condition on port 2
PGOOD1
4
R
Power-good condition on port 1
PWR_EN4
3
R
Power is enabled on port 4
PWR_EN3
2
R
Power is enabled on port 3
PWR_EN2
1
R
Power is enabled on port 2
PWR_EN1
0
R
Power is enabled on port 1
A3, A2, A1, A0 (Table 15) represent the 4 LSBs of the
MAX5965A/MAX5965B address (Table 4). During a
reset, the device latches into R11h. These 4 bits
address from the corresponding inputs as well as the
state of the MIDSPAN and AUTO inputs. Changes to
those inputs during normal operation are ignored.
Table 15. Address Input Status Register
ADDRESS = 11h
SYMBOL
Reserved
BIT
R/W
7
R
DESCRIPTION
Reserved
Reserved
6
R
Reserved
A3
5
R
Device address, A3 pin latched-in status
A2
4
R
Device address, A2 pin latched-in status
A1
3
R
Device address, A1 pin latched-in status
A0
2
R
Device address, A0 pin latched-in status
MIDSPAN
1
R
MIDSPAN input’s latched-in status
AUTO
0
R
AUTO input’s latched-in status
32
______________________________________________________________________________________
High-Power, Quad, Monolithic, PSE Controllers
for Power over Ethernet
A reset sets R12h = AAAAAAAAb where A represents
the latched-in state of the AUTO input prior to the reset.
Use software to change the mode of operation.
Software resets of ports (RESET_P_ bit, Table 23) do
not affect the mode register.
Table 16a. Operating Mode Register
ADDRESS = 12h
SYMBOL
DESCRIPTION
BIT
R/W
P4_M1
7
R/W
MODE[1] for port 4
P4_M0
6
R/W
MODE[0] for port 4
P3_M1
5
R/W
MODE[1] for port 3
P3_M0
4
R/W
MODE[0] for port 3
P2_M1
3
R/W
MODE[1] for port 2
P2_M0
2
R/W
MODE[0] for port 2
P1_M1
1
R/W
MODE[1] for port 1
P1_M0
0
R/W
MODE[0] for port 1
Table 16b. Operating Mode Status
MODE
DESCRIPTION
00
Shutdown
01
Manual
10
Semi-auto
11
Auto
Setting DCD_EN_ to 1 enables the DC load disconnect
detection feature (Table 17). Setting ACD_EN_ to 1
enables the AC load disconnect feature. If enabled, the
load disconnect detection starts during power mode
and after startup when the corresponding PGOOD_ bit
in register R10h (Table 14) goes high. A reset sets
R13h = 0000AAAAb where A represents the latched-in
state of the AUTO input prior to the reset.
Table 17. Load Disconnect Detection Enable Register
ADDRESS = 13h
SYMBOL
DESCRIPTION
BIT
R/W
ACD_EN4
7
R/W
Enable AC disconnect detection on port 4
ACD_EN3
6
R/W
Enable AC disconnect detection on port 3
ACD_EN2
5
R/W
Enable AC disconnect detection on port 2
ACD_EN1
4
R/W
Enable AC disconnect detection on port 1
DCD_EN4
3
R/W
Enable DC disconnect detection on port 4
DCD_EN3
2
R/W
Enable DC disconnect detection on port 3
DCD_EN2
1
R/W
Enable DC disconnect detection on port 2
DCD_EN1
0
R/W
Enable DC disconnect detection on port 1
______________________________________________________________________________________
33
MAX5965A/MAX5965B
The MAX5965A/MAX5965B use 2 bits for each port to
set the mode of operation. Set the modes according to
Table 16a and 16b.
MAX5965A/MAX5965B
High-Power, Quad, Monolithic, PSE Controllers
for Power over Ethernet
Setting DET_EN_/CLASS_EN_ to 1 (Table 18) enables
load detection/classification, respectively. Detection
always has priority over classification. To perform classification without detection, set the DET_EN_ bit low
and CLASS_EN_ bit high.
In manual mode, R14h works like a pushbutton. Set the
bits high to begin the corresponding routine. The bit
clears after the routine finishes.
When entering auto mode, R14h defaults to FFh. When
entering semi or manual modes, R14h defaults to 00h.
A reset or power-up sets R14h = AAAAAAAAb where A
represents the latched-in state of the AUTO input prior
to the reset.
Table 18. Detection and Classification Enable Register
ADDRESS = 14h
SYMBOL
DESCRIPTION
BIT
R/W
CLASS_EN4
7
R/W
Enable classification on port 4
CLASS_EN3
6
R/W
Enable classification on port 3
CLASS_EN2
5
R/W
Enable classification on port 2
CLASS_EN1
4
R/W
Enable classification on port 1
DET_EN4
3
R/W
Enable detection on port 4
DET_EN3
2
R/W
Enable detection on port 3
DET_EN2
1
R/W
Enable detection on port 2
DET_EN1
0
R/W
Enable detection on port 1
EN_HP_CL_, EN_HP_ALL together with CL_DISC
(R17h[2]) and ENx_CL6 (R1Ch[7:4]) are used to program
the high-power mode. See Table 3 for details.
Setting BCKOFF_ to 1 (Table 19) enables cadence timing on each port where the port backs off and waits
2.2s after each failed load discovery detection. The
IEEE 802.3af standard requires a PSE that delivers
power through the spare pairs (midspan PSE) to have
cadence timing.
A reset or power-up sets R15h = 0000XXXXb where ‘X’
is the logic AND of the MIDSPAN and AUTO inputs.
Table 19. Backoff and High-Power Enable Register
ADDRESS = 15h
SYMBOL
DESCRIPTION
BIT
R/W
EN_HP_ALL
7
R/W
High-power detection enabled
EN_HP_CL6
6
R/W
Class 6 PD high-power enabled
EN_HP_CL5
5
R/W
Class 5 PD high-power enabled
EN_HP_CL4
4
R/W
Class 4 PD high-power enabled
BCKOFF4
3
R/W
Enable cadence timing on port 4
BCKOFF3
2
R/W
Enable cadence timing on port 3
BCKOFF2
1
R/W
Enable cadence timing on port 2
BCKOFF1
0
R/W
Enable cadence timing on port 1
34
______________________________________________________________________________________
High-Power, Quad, Monolithic, PSE Controllers
for Power over Ethernet
Set the bits in R16h to scale the tSTART, tFAULT, and
tDISC to a multiple of their nominal value specified in the
Electrical Characteristics table.
When the MAX5965A/MAX5965B shut down a port due
to an extended overcurrent condition (either during
startup or normal operation), if RSTR_EN is set high, the
part does not allow the port to power back on before
the restart timer (Table 20b) returns to zero. This effectively sets a minimum duty cycle that protects the external MOSFET from overheating during prolonged output
overcurrent conditions. A reset sets R16h = 00h.
Table 20a. Timing Configuration Register
ADDRESS = 16h
SYMBOL
DESCRIPTION
BIT
R/W
RSTR[1]
7
R/W
Restart timer programming bit 1
RSTR[0]
6
R/W
Restart timer programming bit 0
TSTART[1]
5
R/W
Startup timer programming bit 1
TSTART[0]
4
R/W
Startup timer programming bit 0
TFAULT[1]
3
R/W
Overcurrent timer programming bit 1
TFAULT[0]
2
R/W
Overcurrent timer programming bit 0
TDISC[1]
1
R/W
Load disconnect timer programming bit 1
TDISC[0]
0
R/W
Load disconnect timer programming bit 0
Table 20b. Startup, Fault, and Load Disconnect Timer Values for Timing Register
BIT [1:0]
(ADDRESS = 16h)
RSTR
tDISC
tSTART
tFAULT
00
16 x tFAULT
tSTART nominal (60ms, typ)
1/2 x tSTART nominal
tFAULT nominal (60ms, typ)
1/2 x tFAULT nominal
01
32 x tFAULT
tDISC nominal (350ms, typ)
1/4 x tDISC nominal
10
64 x tFAULT
1/2 x tDISC nominal
2 x tSTART nominal
2 x tFAULT nominal
11
0 x tFAULT
2 x tDISC nominal
4 x tSTART nominal
4 x tFAULT nominal
______________________________________________________________________________________
35
MAX5965A/MAX5965B
TSTART[1,0] (Table 20a) programs the startup timers.
Startup time is the time the port is allowed to be in current limit during startup. TFAULT[1,0] programs the
fault time. Fault time is the time allowed for the port to
be in current limit during normal operation. RSTR[1,0]
programs the discharge rate of the TFAULT_ counter
and effectively sets the time the port remains off after
an overcurrent fault. TDISC[1,0] programs the load disconnect detection time. The device turns off power to
the port if it fails to provide a minimum power maintenance signal for longer than the load disconnect detection time (tDISC).
MAX5965A/MAX5965B
High-Power, Quad, Monolithic, PSE Controllers
for Power over Ethernet
Setting CL_DISC to 1 (Table 21) enables port over class
current protection, where the MAX5965A/MAX5965B
scales down the overcurrent limit (VFLT_LIM) according
to the port classification status. This feature provides
protection to the system against PDs that violate their
maximum class current allowance.
The MAX5965 is programmed to switch to a high-power
configuration and HP_TIME is low, the higher current setting is enabled only after a successful startup so that the
PD powers up as a normal 15W device. If HP_TIME is set
together with EN_HP_ALL, the higher current setting will
be active before startup. For Classes 4, 5, and 6, the
corresponding enable bit in register R15h must be set
together with EN_HP_ALL. In any other cases, the current level defaults to Class 0.
CL_DISC, together with EN_HP_CL_ (R15h[6:4]),
EN_HP_ALL (R15h[7]), and ENx_CL6 (R1Ch[7:4]) are
used to program the high-power mode. See Table 3 for
details.
Setting OUT_ISO high (Table 21), forces DET_ to a
high-impedance state.
A reset sets R17h = 0xC0.
Table 21. Miscellaneous Configurations 1 Register
ADDRESS = 17h
SYMBOL
DESCRIPTION
BIT
R/W
INT_EN
7
R/W
RSTR_EN
6
R/W
Reserved
5
—
Reserved
Reserved
4
—
Reserved
POFF_CL
3
R
A logic-high prevents power-up after a classification failure (I > 50mA, valid only in AUTO
mode)
CL_DISC
2
R/W
A logic-high enables reduced current-limit voltage threshold (VFLT_LIM) according to port
classification result
OUT_ISO
1
R/W
Forces DET_ to high impedance. Does not interfere with other circuit operation.
HP_TIME
0
R/W
Enables high power after startup.
A logic-high enables INT functionality
A logic-high enables the autorestart protection time off (as set by the RSTR[1:0] bits)
Power-enable pushbutton for semi and manual modes
is found in Table 22. Setting PWR_ON_ to 1 turns on
power to the corresponding port. Setting PWR_OFF_ to
1 turns off power to the port. PWR_ON_ is ignored when
the port is already powered and during shutdown.
PWR_OFF_ is ignored when the port is already off and
during shutdown. After execution, the bits reset to 0.
During detection or classification, if PWR_ON_ goes
high, the MAX5965A/MAX5965B gracefully terminate
the current operation and turn on power to the port. The
MAX5965A/MAX5965B ignore the PWR_ON_ in auto
mode. A reset sets R19h = 00h.
Table 22. Power-Enable Pushbuttons Register
ADDRESS = 19h
SYMBOL
DESCRIPTION
BIT
R/W
PWR_OFF4
7
W
A logic-high powers off port 4
PWR_OFF3
6
W
A logic-high powers off port 3
PWR_OFF2
5
W
A logic-high powers off port 2
PWR_OFF1
4
W
A logic-high powers off port 1
PWR_ON4
3
W
A logic-high powers on port 4
PWR_ON3
2
W
A logic-high powers on port 3
PWR_ON2
1
W
A logic-high powers on port 2
PWR_ON1
0
W
A logic-high powers on port 1
36
______________________________________________________________________________________
High-Power, Quad, Monolithic, PSE Controllers
for Power over Ethernet
event registers of that port. After execution, the bits
reset to 0. Writing a 1 to RESET_IC causes a global
software reset, after which the register map is set back
to its reset state. A reset sets R1Ah = 00h.
Table 23. Global Pushbuttons Register
ADDRESS = 1Ah
SYMBOL
BIT
DESCRIPTION
R/W
CLR_INT
7
W
A logic-high clears all interrupts
Reserved
6
—
Reserved
Reserved
5
—
Reserved
RESET_IC
4
W
A logic-high resets the MAX5965A/MAX5965B
RESET_P4
3
W
A logic-high resets port 4
RESET_P3
2
W
A logic-high resets port 3
RESET_P2
1
W
A logic-high resets port 2
RESET_P1
0
W
A logic-high resets port 1
The ID register (Table 24) keeps track of the device ID
number and revision. The MAX5965A/MAX5965B’s
ID_CODE[4:0] = 11001b. Contact the factory for
REV[2:0] value.
Table 24. ID Register
ADDRESS = 1Bh
SYMBOL
ID_CODE
REV
DESCRIPTION
BIT
R/W
7
R
ID_CODE[4]
6
R
ID_CODE[3]
5
R
ID_CODE[2]
4
R
ID_CODE[1]
3
R
ID_CODE[0]
2
R
REV[2]
1
R
REV[1]
0
R
REV[0]
______________________________________________________________________________________
37
MAX5965A/MAX5965B
Writing a 1 to CLR_INT (Table 23) clears all the event
registers and the corresponding interrupt bits in register R00h. Writing a 1 to RESET_P_ turns off power to the
corresponding port and resets only the status and
MAX5965A/MAX5965B
High-Power, Quad, Monolithic, PSE Controllers
for Power over Ethernet
Enable 2-event classification for a port by setting the corresponding ENx_CL6 bit (Table 25). When the bit is enabled,
the classification cycle will be repeated three times at
21.3ms intervals. The device keeps the output voltage
around -9V between each cycle. The repetition of the classification cycles enables discovering of class 6 PDs. The
ENx_CL6 bit is active only in auto- or semi-mode.
Enable the SMODE function (Table 25) by setting
EN_WHDOG (R1Fh[7]) to 1. The SMODE_ bit goes high
when the watchdog counter reaches zero and the
port(s) switch over to hardware-controlled mode.
SMODE_ also goes high each and every time the software tries to power on a port, but is denied since the
port is in hardware mode. A reset sets R1Ch = 00h.
Note: Performing three consecutive classifications in
manual mode is not the same as performing 2-event
classification in semi or auto mode.
Table 25. SMODE and 2-Event Enable Register
ADDRESS = 1Ch
DESCRIPTION
EN4_CL6
7
CoR or
R/W
R/W
EN3_CL6
6
R/W
Port 3 2-event classification enabled
EN2_CL6
5
R/W
Port 2 2-event classification enabled
EN1_CL6
4
R/W
Port 1 2-event classification enabled
SMODE4
3
CoR
Port 4 hardware control flag
SMODE3
2
CoR
Port 3 hardware control flag
SMODE2
1
CoR
Port 2 hardware control flag
SMODE1
0
CoR
Port 1 hardware control flag
SYMBOL
BIT
Port 4 2-event classification enabled
Set EN_WHDOG (R1Fh[7]) to 1 to enable the watchdog
function. When activated, the watchdog timer counter,
WDTIME[7:0], continuously decrements toward zero
once every 164ms. Once the counter reaches zero
(also called watchdog expiry), the MAX5965A/
MAX5965B enter hardware-controlled mode and each
port shifts to a mode set by the HWMODE_ bit in register R1Fh (Table 27). Use software to set WDTIME
(Table 26) and continuously set this register to some
nonzero value before the register reaches zero to pre-
vent a watchdog expiry. In this way, the software gracefully manages the power to ports upon a system crash
or switchover.
While in hardware-controlled mode, the MAX5965A/
MAX5965B ignore all requests to turn the power on and
the flag SMODE_ indicates that the hardware has taken
control of the MAX5965A/MAX5965B operation. In addition, the software is not allowed to change the mode of
operation in hardware-controlled mode. A reset sets
R1Eh = 00h.
Table 26. Watchdog Register
ADDRESS = 1Eh
SYMBOL
WDTIME
38
DESCRIPTION
BIT
R/W
7
R/W
WDTIME[7]
6
R/W
WDTIME[6]
5
R/W
WDTIME[5]
4
R/W
WDTIME[4]
3
R/W
WDTIME[3]
2
R/W
WDTIME[2]
1
R/W
WDTIME[1]
0
R/W
WDTIME[0]
______________________________________________________________________________________
High-Power, Quad, Monolithic, PSE Controllers
for Power over Ethernet
the bits in register R12h to 00. A high in HWMODE_
switches the port into auto mode by setting the bits in
register R12h to 11. If WD_INT_EN is set, an interrupt is
sent if any of the SMODE bits are set. A reset sets R1Fh
= 00h.
Table 27. Switch Mode Register
ADDRESS = 1Fh
SYMBOL
BIT
DESCRIPTION
R/W
EN_WHDOG
7
R/W
A logic-high enables the watchdog function
WD_INT_EN
6
R/W
Enables interrupt on SMODE_ bits
Reserved
5
—
Reserved
Reserved
4
—
Reserved
HWMODE4
3
R/W
Port 4 switches to AUTO if logic-high and to SHUTDOWN if logic-low when watchdog timer
expires
HWMODE3
2
R/W
Port 3 switches to AUTO if logic-high and to SHUTDOWN if logic-low when watchdog timer
expires
HWMODE2
1
R/W
Port 2 switches to AUTO if logic-high and to SHUTDOWN if logic-low when watchdog timer
expires
HWMODE1
0
R/W
Port 1 switches to AUTO if logic-high and to SHUTDOWN if logic-low when watchdog timer
expires
The CLC_EN enables the large capacitor detection feature. When CLC_EN is set the device can recognize a
capacitor load up to 150µF. If the CLC_EN is reset, the
MAX5965A/MAX5965B perform normal detection.
AC_TH allows programming of the threshold of the AC
disconnect comparator. The threshold is defined as a
current since the comparators verify that the peak of
the current pulses sensed at the DET_ input exceed a
preset threshold. The current threshold is defined as
follows:
IAC_TH = 226.68µA + 28.33 x NAC_TH
where NAC_TH is the decimal value of AC_TH.
When set low, DET_BY inhibits port power-on if the discovery detection was bypassed in auto mode. When
set high, DET_BY allows the device to turn on power to
a non-IEEE 802.3af load without doing detection. If
OSCF_RS is set high, the OSC_FAIL bit is ignored. A
reset or power-up sets R23h = 04h. Default IAC_TH is
340µA.
Table 28. Program Register
ADDRESS = 23h
SYMBOL
DESCRIPTION
BIT
R/W
Reserved
7
—
Reserved
Reserved
6
—
Reserved
CLC_EN
5
R/W
Large capacitor detection enable
DET_BY
4
R/W
Enables skipping detection in AUTO mode
OSCF_RS
AC_TH
3
R/W
OSC_FAIL reset bit
2
R/W
AC_TH[2]
1
R/W
AC_TH[1]
0
R/W
AC_TH[0]
______________________________________________________________________________________
39
MAX5965A/MAX5965B
Setting EN_WHDOG (Table 27) high activates the
watchdog counter. When the counter reaches zero, the
port switches to the hardware-controlled mode determined by the corresponding HWMODE_ bit. A low in
HWMODE_ switches the port into shutdown by setting
MAX5965A/MAX5965B
High-Power, Quad, Monolithic, PSE Controllers
for Power over Ethernet
HP[2:0] programs the default power setting that is written upon the discovery of a class 4, 5, or 6 PD. A reset
or power-up sets R24h = 00h.
Table 29. High-Power Mode Register
ADDRESS = 24h
SYMBOL
Reserved
HP
Reserved
DESCRIPTION
BIT
R/W
7
—
6
R/W
HP[2]
5
R/W
HP[1]
4
R/W
HP[0]
3
—
Reserved
2
—
Reserved
1
—
Reserved
0
—
Reserved
Reserved
Table 30. Reserved Register (25h)
ADDRESS = 25h
SYMBOL
Reserved
DESCRIPTION
BIT
R/W
7
—
Reserved
6
—
Reserved
5
—
Reserved
4
—
Reserved
3
—
Reserved
2
—
Reserved
1
—
Reserved
0
—
Reserved
Table 31. Reserved Register (26h)
ADDRESS = 26h
SYMBOL
Reserved
40
DESCRIPTION
BIT
R/W
7
—
Reserved
6
—
Reserved
5
—
Reserved
4
—
Reserved
3
—
Reserved
2
—
Reserved
1
—
Reserved
0
—
Reserved
______________________________________________________________________________________
High-Power, Quad, Monolithic, PSE Controllers
for Power over Ethernet
desired output power. Table 33 sets the current-limit
scaling register. A reset or power-up sets R29h = 00h.
Table 32. Miscellaneous Configurations 2
Table 33. Current-Limit Scaling Register
ADDRESS = 29h
SYMBOL
Reserved
LSC_EN
IVEE
IVEE[1:0]
(ADDRESS = 29h)
CURRENT LIMIT
(%)
Reserved
00
Default
Reserved
01
-5
—
Reserved
10
-10
4
—
Reserved
11
-15
3
—
Reserved
2
—
LSC_EN
1
R/W
IVEE[1]
0
R/W
IVEE[0]
BIT
R/W
7
—
6
—
5
DESCRIPTION
The three ICUT_ bits (Tables 34a and 34b) allow programming of the current-limit and overcurrent thresholds
in excess of the IEEE 802.3af standard limit. The
MAX5965A/MAX5965B can automatically set the ICUT
register or can be manually written to by the software
(see Table 3).
Class 1 and 2 limits can also be programmed by software independently from the classification status. See
Table 3. A reset or power-up sets R2Ah = R2Bh = 00h.
Table 34a. ICUT Registers 1 and 2
ADDRESS = 2Ah
SYMBOL
Reserved
ICUT2
Reserved
ICUT1
DESCRIPTION
BIT
R/W
7
—
Reserved
6
R/W
ICUT2[2]
5
R/W
ICUT2[1]
4
R/W
ICUT2[0]
3
—
Reserved
2
R/W
ICUT1[2]
1
R/W
ICUT1[1]
0
R/W
ICUT1[0]
Table 34b. ICUT Registers 3 and 4
ADDRESS = 2Bh
SYMBOL
Reserved
ICUT4
Reserved
ICUT3
BIT
DESCRIPTION
R/W
7
—
Reserved
6
R/W
ICUT4[2]
5
R/W
ICUT4[1]
4
R/W
ICUT4[0]
3
—
Reserved
2
R/W
ICUT3[2]
1
R/W
ICUT3[1]
0
R/W
ICUT3[0]
______________________________________________________________________________________
41
MAX5965A/MAX5965B
The IVEE bits enable the current-limit scaling (Table
32). This feature is used to reduce the current limit for
systems running at higher voltage to maintain the
MAX5965A/MAX5965B
High-Power, Quad, Monolithic, PSE Controllers
for Power over Ethernet
Table 34c. ICUT Register Bit Values for Current-Limit Threshold
ICUT_[2:0] (ADDRESS = 2Ah, 2Bh)
SCALE FACTOR
TYPICAL CURRENT-LIMIT THRESHOLD (mA)
000
1x
375
001
1.5x
563
010
1.75x
656
011
2x
750
100
2.25x
844
101
2.5x
938
110
0.3x
Class 1
111
0.53x
Class 2
Table 35a. Classification Status Registers
ADDRESS = 2Ch, 2Dh, 2Eh, 2Fh
SYMBOL
Reserved
DESCRIPTION
BIT
R/W
7
—
Reserved
6
—
Reserved
Table 35b. Class Sequence States
CLASS_[5:0]
(ADDRESS = 2Ch, 2Dh,
2Eh, 2Fh)
CLASS
SEQUENCE
ICUT_[2:0]
CLASS_[5:0]
(ADDRESS = 2Ch, 2Dh,
2Eh, 2Fh)
CLASS
SEQUENCE
ICUT_[2:0]
000000
000 (Class 0)
000
010101
333 (Class 3)
000
000001
001
000
010110
004
000
040
000
000010
010
HP[2:0]
010111
000011
011
000
011000
044
000
000100
100
000
011001
400
000
HP[2:0]
011010
404
000
000101
42
101
000110
110
000
011011
440
000
000111
111 (Class 1)
110
011100
444 (Class 4)
HP[2:0]
001000
002
000
011101
005
000
001001
020
011
011110
050
000
055
000
001010
022
000
011111
001011
200
000
100000
500
000
001100
202
100
100001
505
000
550
000
001101
220
000
100010
001110
222 (Class 2)
111
100011
555 (Class 5)
HP[2:0]
001111
003
000
100100
Reserved
000
Reserved
000
010000
030
010
100101
010001
033
000
100110
Reserved
000
010010
300
000
100111
Reserved
000
Illegal
000
Illegal
000
010011
303
010
101000
010100
330
000
101001
______________________________________________________________________________________
High-Power, Quad, Monolithic, PSE Controllers
for Power over Ethernet
CLASS_[5:0]
(ADDRESS = 2Ch, 2Dh,
2Eh, 2Fh)
CLASS
SEQUENCE
ICUT_[2:0]
CLASS_[5:0]
(ADDRESS = 2Ch, 2Dh,
2Eh, 2Fh)
CLASS
SEQUENCE
ICUT_[2:0]
101010
Illegal
000
110101
Reserved
000
101011
Illegal
000
110110
Reserved
000
101100
Illegal
000
110111
Reserved
000
101101
Illegal
000
111000
Reserved
000
101110
Illegal
000
111001
Reserved
000
101111
Illegal
000
111010
Reserved
000
110000
Reserved
000
111011
Reserved
000
110001
Reserved
000
111100
Reserved
000
110010
Reserved
000
111101
Reserved
000
110011
Reserved
000
111110
Reserved
000
110100
Reserved
000
111111
Reserved
000
When the ENx_CL6 (R1Ch[7:4]) bits are set, 2-event
classification is enabled. Classification is repeated
three times and the classification results are set
according to Table 35b.
A Class 6 PD is defined by any sequence of the type
[00x, 0x0, 0xx, x00, x0x, xx0] where ‘x’ can be 1, 2, 3,
4, or 5. All sequences made by the same class result
define the class itself (for example, 222 defines Class
2). Any other sequence will be considered illegal and
coded as 101xxx. For example, a sequence 232 or 203
will be illegal. The illegal sequences all default to class
0. A reset or power-up sets R2Ch = R2Dh = R2Eh =
R2Fh = 00h.
The MAX5965A/MAX5965B provide current readout for
each port during classification and normal power
mode. The current per port information is separated
into 9 bits. They are organized into two consecutive
registers for each one of the ports. The information can
be quickly retrieved using the autoincrement option of
the address pointer. To avoid the LSB register changing while reading the MSB, the information is frozen
once the addressing byte points to any of the current
readout registers.
During power mode, the current value can be calculated as
IPORT = NIPD_ x 1.953125mA
During classification, the current is
ICLASS = NIPD_ x 0.0975mA
where NIPD_ is the decimal value of the 9-bit word. The
ADC saturates both at full scale and at zero. A reset
sets R30h to R37h = 00h.
Table 36. Current Registers
ADDRESS = 30h, 31h, 32h, 33h, 34h,
35h, 36h, 37h
SYMBOL
IPD_
DESCRIPTION
BIT
R/W
7
RO
IPD_[8]
6
RO
IPD_[7]
5
RO
IPD_[6]
4
RO
IPD_[5]
3
RO
IPD_[4]
2
RO
IPD_[3]
1
RO
IPD_[2]
0
RO
IPD_[1]/IPD_[0]
______________________________________________________________________________________
43
MAX5965A/MAX5965B
Table 35b. Class Sequence States (continued)
MAX5965A/MAX5965B
High-Power, Quad, Monolithic, PSE Controllers
for Power over Ethernet
Table 37. Register Summary
ADDR
REGISTER NAME
R/W
PORT
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
RESET
STATE
INTERRUPTS
00h
Interrupt
RO
G
SUP_FLT
TSTR_FLT
IMAX_FLT
CL_END
DET_END
LD_DISC
PG_INT_
PEN_INT_
0000,0000
01h
Interrupt Mask
R/W
G
MASK7
MASK6
MASK5
MASK4
MASK3
MASK2
MASK1
MASK0
AAA0,0A00
PG_CHG4
PG_CHG3
PG_CHG2
PG_CHG1
PWEN_
CHG4
PWEN_
CHG3
PWEN_
CHG2
PWEN_
CHG1
0000,0000
EVENTS
02h
Power Event
RO
4321
03h
Power Event CoR
CoR
—
04h
Detect Event
RO
4321
05h
Detect Event CoR
CoR
—
06h
Fault Event
RO
4321
07h
Fault Event CoR
CoR
—
08h
Startup Event
RO
4321
09h
Startup Event CoR
CoR
—
0Ah
Supply Event
RO
4321
0Bh
Supply Event CoR
CoR
—
0Ch
Port 1 Status
RO
0Dh
Port 2 Status
RO
0Eh
Port 3 Status
0Fh
CL_END4
LD_DISC4
IVC4
CL_END3
LD_DISC3
IVC3
CL_END2
LD_DISC2
IVC2
CL_END1
LD_DISC1
IVC1
DET_END4
IMAX_FLT4
STRT_FLT4
DET_END3
IMAX_FLT3
STRT_FLT3
DET_END2
IMAX_FLT2
STRT_FLT2
DET_END1
IMAX_FLT1
STRT_FLT1
—
0000,0000
—
0000,0000
—
0000,0000
—
—
TSD
VDD_OV
VDD_UV
VEE_UVLO
VEE_OV
VEE_UV
OSC_FAIL
VDD_UVLO
1
Reserved
CLASS1[2]
CLASS1[1]
CLASS1[0]
Reserved
DET_ST1[2]
DET_ST1[1]
DET_ST1[0]
0000,0000
2
Reserved
CLASS2[2]
CLASS2[1]
CLASS2[0]
Reserved
DET_ST2[2]
DET_ST2[1]
DET_ST2[0]
0000,0000
RO
3
Reserved
CLASS3[2]
CLASS3[1]
CLASS3[0]
Reserved
DET_ST3[2]
DET_ST3[1]
DET_ST3[0]
0000,0000
Port 4 Status
RO
4
Reserved
CLASS4[2]
CLASS4[1]
CLASS4[0]
Reserved
DET_ST4[2]
DET_ST4[1]
DET_ST4[0]
0000,0000
10h
Power Status
RO
4321
PGOOD4
PGOOD3
PGOOD2
PGOOD1
PWR_EN4
PWR_EN3
PWR_EN2
PWR_EN1
0000,0000
11h
Address Input Status
RO
G
Reserved
Reserved
A3
A2
A1
A0
MIDSPAN
AUTO
00A3A2,
A1A0MA
—
STATUS
CONFIGURATION
12h
Operating Mode
R/W
4321
P4_M1
P4_M0
P3_M1
P3_M0
P2_M1
P2_M0
P1_M1
P1_M0
AAAA,AAAA
13h
Load Disconnect
Detection Enable
R/W
4321
ACD_EN4
ACD_EN3
ACD_EN2
ACD_EN1
DCD_EN4
DCD_EN3
DCD_EN2
DCD_EN1
0000,AAAA
14h
Detection and
Classification Enable
R/W
4321
CLASS_EN4
CLASS_EN3
CLASS_EN2
CLASS_EN1
DET_EN4
DET_EN3
DET_EN2
DET_EN1
AAAA,AAAA
15h
Backoff and HighPower Enable
R/W
4321
EN_HP_ALL
EN_HP_CL6
EN_HP_CL5
EN_HP_CL4
BCKOFF4
BCKOFF3
BCKOFF2
BCKOFF1
0000,XXXX
16h
Timing Configuration
R/W
G
RSTR[1]
RSTR[0]
TSTART[1]
TSTART[0]
TFAULT[1]
TFAULT[0]
TDISC[1]
TDISC[0]
0000,0000
17h
Miscellaneous
Configuration 1
R/W
G
INT_EN
RSTR_EN
Reserved
Reserved
POFF_CL
CL_DISC
OUT_ISO
HP_TIME
1100,0000
PUSHBUTTONS
18h
Reserved
R/W
G
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
—
19h
Power Enable
WO
4321
PWR_OFF4
PWR_OFF3
PWR_OFF2
PWR_OFF1
PWR_ON4
PWR_ON3
PWR_ON2
PWR_ON1
0000,0000
1Ah
Global
WO
G
CLR_INT
Reserved
Reserved
RESET_IC
RESET_P4
RESET_P3
RESET_P2
RESET_P1
0000,0000
ID
RO
G
ID_CODE[4]
ID_CODE[3]
ID_CODE[2]
ID_CODE[1]
ID_CODE[0]
REV[2]
REV[1]
REV[0]
1100,0000
SMODE and 2-Event
Enable
CoR
or
R/W
4321
EN4_CL6
EN3_CL6
EN2_CL6
EN1_CL6
SMODE4
SMODE3
SMODE2
SMODE1
0000,0000
GENERAL
1Bh
1Ch
1Dh
Reserved
—
G
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
—
1Eh
Watchdog
R/W
G
WDTIME[7]
WDTIME[6]
WDTIME[5]
WDTIME[4]
WDTIME[3]
WDTIME[2]
WDTIME[1]
WDTIME[0]
0000,0000
1Fh
Switch Mode
R/W
4321
EN_WHDOG
WD_INT_EN
Reserved
Reserved
HWMODE4
HWMODE3
HWMODE2
HWMODE1
0000,0000
44
______________________________________________________________________________________
High-Power, Quad, Monolithic, PSE Controllers
for Power over Ethernet
ADDR
REGISTER NAME
R/W
PORT
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
RESET
STATE
MAXIM RESERVED
20h
Reserved
—
G
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
—
21h
Reserved
—
G
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
—
22h
Reserved
—
G
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
—
23h
Program
R/W
4321
Reserved
Reserved
CLC_EN
DET_BY
OSCF_RS
AC_TH[2]
AC_TH[1]
AC_TH[0]
—
24h
High-Power Mode
R/W
G
Reserved
HP[2]
HP[1]
HP[0]
Reserved
Reserved
Reserved
Reserved
0000,0000
25h
Reserved
—
G
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
0000,0000
26h
Reserved
—
G
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
0000,0000
27h
Reserved
—
G
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
—
28h
Reserved
—
G
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
—
29h
Miscellaneous
Configuration 2
R/W
1234
Reserved
Reserved
Reserved
Reserved
Reserved
LSC_EN
IVEE[1]
IVEE[0]
0000,0000
2Ah
ICUT Registers 1 and 2 R/W
21
Reserved
ICUT2[2]
ICUT2[1]
ICUT2[0]
Reserved
ICUT1[2]
ICUT1[1]
ICUT1[0]
0000,0000
2Bh
ICUT Registers 3 and 4 R/W
43
Reserved
ICUT4[2]
ICUT4[1]
ICUT4[0]
Reserved
ICUT3[2]
ICUT3[1]
ICUT3[0]
0000,0000
CLASSIFICATION STATUS REGISTERS
2Ch
Port 1 Class
RO
1
Reserved
Reserved
CLASS1[5]
CLASS1[4]
CLASS1[3]
CLASS1[2]
CLASS1[1]
CLASS1[0]
0000,0000
2Dh
Port 2 Class
RO
2
Reserved
Reserved
CLASS2[5]
CLASS2[4]
CLASS2[3]
CLASS2[2]
CLASS2[1]
CLASS2[0]
0000,0000
2Eh
Port 3 Class
RO
3
Reserved
Reserved
CLASS3[5]
CLASS3[4]
CLASS3[3]
CLASS3[2]
CLASS3[1]
CLASS3[0]
0000,0000
2Fh
Port 4 Class
RO
4
Reserved
Reserved
CLASS4[5]
CLASS4[4]
CLASS4[3]
CLASS4[2]
CLASS4[1]
CLASS4[0]
0000,0000
CURRENT REGISTER
30h
Current Port 1 (MSB)
RO
1
IPD1[8]
IPD1[7]
IPD1[6]
IPD1[5]
IPD1[4]
IPD1[3]
IPD1[2]
IPD1[1]
0000,0000
31h
Current Port 1 (LSB)
RO
1
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
IPD1[0]
0000,0000
32h
Current Port 2 (MSB)
RO
2
IPD2[8]
IPD2[7]
IPD2[6]
IPD2[5]
IPD2[4]
IPD2[3]
IPD2[2]
IPD2[1]
0000,0000
33h
Current Port 2 (LSB)
RO
2
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
IPD2[0]
0000,0000
34h
Current Port 3 (MSB)
RO
3
IPD3[8]
IPD3[7]
IPD3[6]
IPD3[5]
IPD3[4]
IPD3[3]
IPD3[2]
IPD3[1]
0000,0000
35h
Current Port 3 (LSB)
RO
3
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
IPD3[0]
0000,0000
36h
Current Port 4 (MSB)
RO
4
IPD4[8]
IPD4[7]
IPD4[6]
IPD4[5]
IPD4[4]
IPD4[3]
IPD4[2]
IPD4[1]
0000,0000
37h
Current Port 4 (LSB)
RO
4
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
IPD4[0]
0000,0000
*UV and UVLO bits of VEE and VDD asserted depends on the order VEE and VDD supplies are brought up.
A = AUTO pin state before reset.
M = MIDSPAN state before reset.
A3...0 = ADDRESS input states before reset.
______________________________________________________________________________________
45
MAX5965A/MAX5965B
Table 37. Register Summary (continued)
High-Power, Quad, Monolithic, PSE Controllers
for Power over Ethernet
MAX5965A/MAX5965B
Applications Information
RJ–45
CONNECTOR
1
3
RX1+
RD1+
RX1-
RD1-
24
1
22
2
1/2 OF
21
H2005A TX1+
4
TD1+*
19
TX1-
PHY
5
3
6
TD1-
-48VOUT
0.1μF
RXT1
23
75Ω
4
0.1μF
5
0.1μF
TXCT1
75Ω
20
1000pF
250VAC
75Ω
75Ω
7
0.1μF
8
-48VRTN
VCC (3.3V)
VDD
ISOLATION
1.8V TO 5V,
(REF TO DGND)
3kΩ
AGND
VDD
180Ω
A0
A1
A2
A3
1kΩ
RESET
INTERNAL
50kΩ PULLUP
3kΩ
HPCL063L
SERIAL INTERFACE
VCCRTN
4.7kΩ
INT
SDAOUT
OPTIONAL BUFFER
180Ω
MIDSPAN
INTERNAL PULLDOWN
(SIGNAL MODE)
MAX5965A
MAX5965B
HPCL063L
OPTIONAL BUFFER
180Ω
INTERNAL PULLDOWN
(MANUAL MODE)
3kΩ
SDAIN
SDA
AUTO
OSC
SINE WAVE
100Hz ±10%
PEAK AMPLITUDE 2.2V ±0.1V
VALLEY AMPLITUDE 0.2V ±0.1V
3kΩ
SCL
HPCL063L
ON
SHD_
SCL
OFF
OPTIONAL BUFFER
DGND
VEE
SENSE_ GATE_
OUT_
0.5Ω
1%
100Ω
DET_
1N4448
1kΩ
0.47μF
100V
SMBJ
58CA
-48V
1N4002
FDT3612
100V, 120mΩ
SOT-223
*USE HALO TG111-HRPE40NY OR
PULSE HX6015NL FOR HIGH POWER
1 OF 4 CHANNELS
Figure 13. PoE System Block Diagram
46
______________________________________________________________________________________
0.1μF
2.2MΩ
-48VOUT
High-Power, Quad, Monolithic, PSE Controllers
for Power over Ethernet
MAX5965A/MAX5965B
RJ–45
CONNECTOR
1
2
DATA
3
6
4
5
7
8
-48VOUT
-48VRTN
VCC (3.3V)
VDD
ISOLATION
1.8V TO 5V
(REF TO DGND)
3kΩ
AGND
VDD
180Ω
A0
A1
A2
A3
1kΩ
RESET
INTERNAL
50kΩ PULLUP
3kΩ
HPCL063L
SERIAL INTERFACE
VCCRTN
4.7kΩ
INT
SDAOUT
OPTIONAL BUFFER
180Ω
SDAIN
OPTIONAL BUFFER
180Ω
INTERNAL PULLDOWN
(MANUAL MODE)
MIDSPAN
INTERNAL PULLDOWN
(SIGNAL MODE)
MAX5965A
MAX5965B
HPCL063L
SDA
AUTO
3kΩ
OSC
SINE WAVE
100Hz ±10%
PEAK AMPLITUDE 2.2V ±0.1V
VALLEY AMPLITUDE 0.2V ±0.1V
3kΩ
SCL
HPCL063L
ON
SHD_
SCL
OFF
OPTIONAL BUFFER
DGND
VEE
SENSE_ GATE_
OUT_
0.5Ω
1%
100Ω
DET_
1kΩ
1N4448
0.47μF
100V
SMBJ
58CA
0.1μF
2.2MΩ
-48VOUT
-48V
1N4002
FDT3612
100V, 120mΩ
SOT-223
1 OF 4 CHANNELS
Figure 14. PoE System Block Diagram
______________________________________________________________________________________
47
MAX5965A/MAX5965B
High-Power, Quad, Monolithic, PSE Controllers
for Power over Ethernet
R10
2Ω
L1
68μH, DO3308P-683
R6
1Ω
D1
DIODES INC.: B1100
C3
15nF
C4
220μF
Sanyo 6SVPA220MAA
R5
1kΩ
GND
+3.3V
R1
2.61kΩ
+3.3V
300mA
C5
4.7μF
Q2
MMBTA56
Q4
MMBTA56
GND
GND
DRAIN
1
2
3
C6
0.47μF
100V
4
V+
MAX5020
VCC
VDD
NDRV
FB
GND
SS_SHDN
CS
8
R8
30Ω
7
6
Q3
MMBTA56
Q1
Si2328 DS
C9
4.7nF
SOURCE
5
C7
0.22μF
C1
0.1μF
C2
0.022μF
GATE
C8
2.2μF
R4
1Ω
-48V
R9
1Ω
R2
6.81kΩ
R7
1.02kΩ
R3
2.61kΩ
-48V
Figure 15. -48V to +3.3V (300mA) Boost Converter Solution for VDIG
Figure 16. Layout Example for Boost Converter Solution for VDIG
48
______________________________________________________________________________________
965 (mils)
1700 (mils)
965 (mils)
1700 (mils)
965 (mils)
1700 (mils)
High-Power, Quad, Monolithic, PSE Controllers
for Power over Ethernet
DESIGNATION
DESCRIPTION
DESIGNATION
DESCRIPTION
C1
0.1µF, 25V ceramic capacitor
C2
0.022µF, 25V ceramic capacitor
C3
15nF, 25V ceramic capacitor
C4
220µF capacitor Sanyo 6SVPA220MAA
C5
4.7µF, 16V ceramic capacitor
C6
0.47µF, 100V ceramic capacitor
R4, R6, R9
C7
0.22µF, 16V ceramic capacitor
R5
1kΩ ±1% resistor
C8
2.2µF, 16V ceramic capacitor
R7
1.02kΩ ±1% resistor
C9
4.7nF, 16V ceramic capacitor
R8
30Ω ±1% resistor
D1
B1100 100V Schottky diode
R10
2Ω ±1% resistor
L1
68µH inductor
Coilcraft DO3308P-683 or equivalent
U1
High-voltage PWM IC
MAX5020ESA (8-pin SO)
Q1
Q2, Q3, Q4
Si2328DS
Vishay n-channel MOSFET, SOT23
MMBTA56 small-signal PNP
R1, R3
2.61kΩ ±1% resistors
R2
6.81kΩ ±1% resistor
1Ω ±1% resistors
Pin Configuration
TOP VIEW
RESET 1
+
36 OSC
2
35 AUTO
INT 3
34 OUT1
MIDSPAN
SCL
4
33 GATE1
SDAOUT
5
32 SENSE1
SDAIN
6
A3
7
30 GATE2
A2
8
29 SENSE2
A1
9
28 VEE
MAX5965A
MAX5965B
31 OUT2
27 OUT3
A0 10
DET1 11
26 GATE3
DET2 12
25 SENSE3
DET3 13
24 OUT4
DET4 14
23 GATE4
DGND 15
22 SENSE4
VDD 16
21 AGND
SHD1 17
20 SHD4
SHD2 18
19 SHD3
SSOP
______________________________________________________________________________________
49
MAX5965A/MAX5965B
Component List for VDIG Supply
High-Power, Quad, Monolithic, PSE Controllers
for Power over Ethernet
MAX5965A/MAX5965B
Typical Operating Circuits
-48V RTN
OUTPUT TO PORT
-48VRTN
VCC (3.3V)
ISOLATION
VDD
1.8V TO 3.7V,
(REF TO DGND)
3kΩ
AGND
VDD
180Ω
A0
A1
A2
A3
1kΩ
RESET
3kΩ
INTERNAL
50kΩ PULLUP
SERIAL INTERFACE
VCCRTN
HPCL063L
180Ω
SDAOUT
OPTIONAL BUFFER
INT
3kΩ
AUTO
INTERNAL PULLDOWN
(MANUAL MODE)
MIDSPAN
INTERNAL PULLDOWN
(SIGNAL MODE)
SDAIN
MAX5965A
MAX5965B
HPCL063L
SDA
OPTIONAL BUFFER
180Ω
4.7kΩ
OSC
3kΩ
N.C.
SCL
HPCL063L
ON
SHD_
SCL
OFF
OPTIONAL BUFFER
DGND
VEE
SENSE_ GATE_
OUT_
0.5Ω
1%
100Ω
DET_
1N4448
-48V
OUTPUT TO
PORT
-48V
FDT3612
100V, 120mΩ
SOT-223
NOTE: ALL SIGNAL PINS ARE REFERENCED TO DGND.
DGND RANGE IS BETWEEN VEE AND (AGND + 4V).
CAN BE UP TO 100kΩ
1 OF 4 CHANNELS
Typical Operating Circuit 1 (without AC Load Removal Detection)
50
______________________________________________________________________________________
High-Power, Quad, Monolithic, PSE Controllers
for Power over Ethernet
-48V RTN
OUTPUT TO PORT
-48VRTN
VCC (3.3V)
ISOLATION
VDD
1.8V TO 3.7V,
(REF TO DGND)
3kΩ
AGND
VDD
180Ω
A0
A1
A2
A3
1kΩ
RESET
3kΩ
INTERNAL
50kΩ PULLUP
SERIAL INTERFACE
VCCRTN
HPCL063L
180Ω
SDAOUT
OPTIONAL BUFFER
INT
3kΩ
AUTO
INTERNAL PULLDOWN
(MANUAL MODE)
MIDSPAN
INTERNAL PULLDOWN
(SIGNAL MODE)
SDAIN
MAX5965A
MAX5965B
HPCL063L
SDA
OPTIONAL BUFFER
180Ω
4.7kΩ
OSC
3kΩ
N.C.
SCL
HPCL063L
ON
SHD_
SCL
OFF
OPTIONAL BUFFER
DGND
VEE
SENSE_ GATE_
OUT_
0.5Ω
1%
100Ω
DET_
1N4448
-48V
OUTPUT TO
PORT
-48V
FDT3612
100V, 120mΩ
SOT-223
NOTE: ALL SIGNAL PINS ARE REFERENCED TO DGND.
DGND RANGE IS BETWEEN VEE AND (AGND + 4V).
CAN BE UP TO 100kΩ
1 OF 4 CHANNELS
Typical Operating Circuit 2 (without AC Load Removal Detection); Alternative DGND Connection
______________________________________________________________________________________
51
MAX5965A/MAX5965B
Typical Operating Circuits (continued)
Typical Operating Circuits (continued)
-48V RTN
OUTPUT TO PORT
-48VRTN
VDD
ISOLATION
VCC (3.3V)
1.8V TO 3.7V,
(REF TO DGND)
3kΩ
AGND
VDD
180Ω
A0
A1
A3
A2
1kΩ
RESET
INTERNAL
50kΩ PULLUP
3kΩ
HPCL063L
VCCRTN
SERIAL INTERFACE
MAX5965A/MAX5965B
High-Power, Quad, Monolithic, PSE Controllers
for Power over Ethernet
4.7kΩ
INT
SDAOUT
OPTIONAL BUFFER
180Ω
SDAIN
OPTIONAL BUFFER
180Ω
INTERNAL PULLDOWN
(MANUAL MODE)
MIDSPAN
INTERNAL PULLDOWN
(SIGNAL MODE)
MAX5965B
HPCL063L
SDA
AUTO
3kΩ
OSC
SINE WAVE
100Hz ±10%
PEAK AMPLITUDE 2.2V ±0.1V
VALLEY AMPLITUDE 0.2V ±0.1V
3kΩ
SCL
HPCL063L
ON
SHD_
SCL
OFF
OPTIONAL BUFFER
DGND
VEE
SENSE_ GATE_
OUT_
0.5Ω
1%
DET_
100Ω
1kΩ
1N4448
0.47μF
100V
-48V
OUTPUT TO
PORT
-48V
NOTE: ALL SIGNAL PINS ARE REFERENCED TO DGND.
DGND MUST BE CONNECTED DIRECTLY TO AGND
FOR AC DISCONNECT DETECTION CIRCUIT TO OPERATE.
1N4002
FDT3612
100V, 120mΩ
SOT-223
CAN BE UP TO 100kΩ
1 OF 4 CHANNELS
Typical Operating Circuit 3 (with AC Load Removal Detection)
Chip Information
PROCESS: BiCMOS
52
Package Information
For the latest package outline information and land patterns, go
to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in
the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the package regardless of RoHS status.
PACKAGE TYPE
PACKAGE CODE
DOCUMENT NO.
36 SSOP
A36-4
21-0040
______________________________________________________________________________________
High-Power, Quad, Monolithic, PSE Controllers
for Power over Ethernet
REVISION
NUMBER
REVISION
DATE
0
7/09
Initial release
1
1/10
Revised Features, Register Map and Description section, and Tables 32 and 37.
DESCRIPTION
PAGES
CHANGED
—
3, 5
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ____________________ 53
© 2010 Maxim Integrated Products
Maxim is a registered trademark of Maxim Integrated Products, Inc.
MAX5965A/MAX5965B
Revision History