Rainbow Electronics MAX5965B User Manual

General Description

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 I

C interface. The MAX5965A/MAX5965B also provide

high-capacitance detection for legacy PDs.

These devices feature an I

C-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.

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.

Applications

Power-Sourcing Equipment (PSE) Switches/Routers Midspan Power Injectors

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 2-

Event Classification)

o Load-Stability Safety Check During Detection

o Supports Both DC and AC Load Removal

Detections

o I

C-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

MAX5965A/MAX5965B

High-Power, Quad, Monolithic, PSE Controllers

for Power over Ethernet

________________________________________________________________

Maxim Integrated Products

19-4593; Rev 0; 7/09

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.

Pin Configuration appears at end of data sheet.

Ordering Information

Denotes a lead(Pb)-free/RoHS-compliant package.

Future product—contact factory for availability.

IEEE is a registered service mark of the Institute of Electrical and Electronics Engineers, Inc.

Selector Guide

PART TEMP RANGE PIN-PACKAGE

MAX5965AEAX+ -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

PART PIN-PACKAGE

MAX5965AEAX+ 36 SSOP No

MAX5965AUAX+ 36 SSOP No

MAX5965BEAX+ 36 SSOP Yes

MAX5965BUAX+ 36 SSOP Yes

AC DISCONNECT

FEATURE

MAX5965A/MAX5965B

High-Power, Quad, Monolithic, PSE Controllers for Power over Ethernet

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

AGND

= 32V to 60V, VEE= 0V, VDDto V

DGND

= +3.3V, all voltages are referenced to VEE, unless otherwise noted. Typical values are at

AGND

= +48V, V

DGND

= +48V, VDD= (V

DGND

+ 3.3V), TA= +25°C. Currents are positive when entering the pin and negative other-

wise.) (Note 2)

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.

(Voltages referenced to VEE, unless otherwise noted.) AGND, DGND, DET_, V

, 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

, 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 (T

= +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 V

. Driving GATE_ higher than 11.4V above VEEmay damage the device.

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

POWER SUPPLIES

Operating Voltage Range

Supply Currents

GATE DRIVER AND CLAMPING

GATE_ Pullup Current I

Weak GATE_ Pulldown Current I

Maximum Pulldown Current I

External Gate Drive V

AGND

DGND

PDW

- V

AGND

VDD to V

OUT_

all logic inputs open, SCL = SDAIN = V INT and SDAOUT unconnected. Measured at

DGND

= VEE, V

AGND in power mode after GATE_ pullup

DIG

All logic inputs high, measured at V

Power mode, gate drive on, V (Note 3)

SHD_ = DGND, V

PDS

= 600mV, V

SENSE

- VEE, power mode, gate drive on,

GATE

= 1µA

32 60

060

, V

= V

DGND

SENSE

GATE_

AGND

= V

_ = VEE, DET_ = AGND,

= V

GATE

= VEE + 10V 42 µA

= VEE + 2V 100 mA

GATE_

2.4 3.6

3.0 3.6

4.8 6.8

0.2 0.4

-40 -50 -65 µA

9 10 11.5 V

MAX5965A/MAX5965B

High-Power, Quad, Monolithic, PSE Controllers

for Power over Ethernet

_______________________________________________________________________________________ 3

ELECTRICAL CHARACTERISTICS (continued)

AGND

= 32V to 60V, VEE= 0V, VDDto V

DGND

= +3.3V, all voltages are referenced to VEE, unless otherwise noted. Typical values are at

AGND

= +48V, V

DGND

= +48V, VDD= (V

DGND

+ 3.3V), TA= +25°C. Currents are positive when entering the pin and negative other-

wise.) (Note 2)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

CURRENT LIMIT

Current-Limit Clamp Voltage V

Overcurrent Threshold After Startup

Foldback Initial OUT_ Voltage V

Foldback Final OUT_ Voltage V

Minimum Foldback Current-Limit Threshold

SENSE_ Input Bias Current V

SU_LIM

FLT_LIM

FLBK_ST

FLBK_END

TH_FBVOUT_

M axi m um V d ur i ng cur r ent l i m i t, V (ICUT = 000) (Note 4)

Overcurrent V allowed for t ≤ t startup; V (IVEE = 00)

OUT_

current-limit trip voltage starts folding back, IVEE = 00

IVEE = 00, ICUT = 000, V which the current-limit trip voltage reaches V

TH_FB

SENSE_

OUT_

- VEE, above which the

= AGND = 60V, IVEE = 00, ICUT = 000 64 mV

= V

S E N S E _

SENSE_

FAULT

= 0V,

al l ow ed

= 0V

OU T_

threshold

after

OUT

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)

ICUT =110 (Class 1)

ICUT = 111 (Class 2)

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

ICUT = 000, ICUT = 110, ICUT = 111

ICUT = 001…101

- V

above

177 186 196

47 55 64

86 94 101

50 V

-5 +5 µA

MAX5965A/MAX5965B

High-Power, Quad, Monolithic, PSE Controllers for Power over Ethernet

4 _______________________________________________________________________________________

ELECTRICAL CHARACTERISTICS (continued)

AGND

= 32V to 60V, VEE= 0V, VDDto V

DGND

= +3.3V, all voltages are referenced to VEE, unless otherwise noted. Typical values are at

AGND

= +48V, V

DGND

= +48V, VDD= (V

DGND

+ 3.3V), TA= +25°C. Currents are positive when entering the pin and negative other-

wise.) (Note 2)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

SUPPLY MONITORS

VEE Undervoltage Lockout V

VEE Undervoltage Lockout Hysteresis

VEE Overvoltage Lockout V

VEE Overvoltage Lockout Hysteresis

VEE Undervoltage V

VDD Overvoltage V

VDD Undervoltage V

VDD Undervoltage Lockout V

VDD Undervoltage Lockout Hysteresis

Thermal Shutdown Threshold T

EEUVLO

EEUVLOH

EE_OV

OVH

EE_UV

DD_OV

DD_UV

DDUVLO

DDHYS

SHD

AGND - VEE, AGND - VEE increasing 28.5 V

P or ts shut d ow n i f AGN D - V V

E E U V L OH

event bit sets and ports shut down if

EE_OV

AGND - V

> V

EE_OV

E E

< V

U V L O

, AGND increasing

62.5 V

event b i t i s set i f AGN D - V

E E _ U V

i ncr easi ng

E E

event bit is set if VDD - V

DD_OV

; VDD increasing

DD_OV

is set if VDD - V

DD_UV

DGND

decreasing

Device operates when VDD - DGND > V

DDUVLO

, VDD increasing

> V

< V

E E

DGND

DD_UV

E E _ U V

, V

40 V

3.82 V

2.7 V

120 mV

Ports shut down and device resets if its junction temperature exceeds this limit,

+150 °C

temperature increasing (Note 5)

Thermal Shutdown Hysteresis T

SHDH

Thermal hysteresis, temperature decreasing (Note 5)

20 °C

OUTPUT MONITOR

OUT_ Input Current I

BOUT

= AGND, all modes 2 µA

OUT

OUT_ discharge current, detection and

Idle Pullup Current at OUT_ I

PGOOD High Threshold PG

PGOOD Hysteresis PG

PGOOD Low-to-High Glitch Filter

PGOOD

DIS

classification off, port shutdown, V

= AGND - 2.8V

OUT_

HYS

- VEE, OUT_ decreasing 1.5 2.0 2.5 V

OUT_

Minimum time PGOOD has to be high to set bit in register 10h

200 265 µA

220 mV

3ms

MAX5965A/MAX5965B

High-Power, Quad, Monolithic, PSE Controllers

for Power over Ethernet

_______________________________________________________________________________________ 5

ELECTRICAL CHARACTERISTICS (continued)

AGND

= 32V to 60V, VEE= 0V, VDDto V

DGND

= +3.3V, all voltages are referenced to VEE, unless otherwise noted. Typical values are at

AGND

= +48V, V

DGND

= +48V, VDD= (V

DGND

+ 3.3V), TA= +25°C. Currents are positive when entering the pin and negative other-

wise.) (Note 2)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

LOAD DISCONNECT

DC Load Disconnect Threshold

AC Load Disconnect Threshold

Oscillator Buffer Gain A

OSC Fail Threshold V

OSC Input Impedance Z

Load Disconnect Timer t

DETECTION

Detection Probe Voltage (First Phase)

Detection Probe Voltage (Second Phase)

Current-Limit Protection I

Short-Circuit Threshold V

DCTH

ACTH

OSC

OSC_FAIL

OSC

DISC

DPH1

DPH2

DLIM

DCP

Minimum V

allowed before disconnect

SENSE

(DC disconnect active), V

Current into DET_, for I < I powers off, ACD_EN_ bit = H; V

2.2V, MAX5965B (Note 6)

DET_/VOSC

, ACD_EN_ bit = H, MAX5965B 2.9 3.0 3.1 V/V

Port does not power on if V and ACD_EN_ bit is high, MAX5965B (Note 7)

OSC input impedance when all the ACD_EN_ are active, MAX5965B

Time from V

SENSE

< V

(Note 8)

AGND - V

during the first detection

DET_

phase

AGND - V

during the second detection

DET_

phase

= AGND, during detection, measure

DET_

current through DET_

If AGND - V

OUT

< V detection phase a short circuit to AGND is detected

OUT_

ACTH

OSC

to gate shutdown

DCTH

after the first

DCP

= 0V

the port

OSC_IN

< V

OSC_FAIL

2.5 3.75 5.0 mV

285 320 360 µA

1.8 2.2 V

100 kΩ

300 400 ms

3.8 4 4.2 V

9.0 9.3 9.6 V

1.5 1.8 2.2 mA

Open-Circuit Threshold I

D_OPEN

Resistor Detection Window R

Resistor Rejection Window R

CLASSIFICATION

Classification Probe Voltage V

Current-Limit Protection I

Classification Current Thresholds

DOK

DBAD

CILIM

First point measurement current threshold for open condition

12.5 µA

(Note 9) 19.0 26.5 kΩ

Detection rejects lower values 15.2

Detection rejects higher values 32

- V

AGND

during classification 16 20 V

DET_

kΩ

DET_ = AGND, during classification 68 80 mA

Class 0, Class 1 5.5 6.5 7.5

Classification current thresholds between classes

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

MAX5965A/MAX5965B

High-Power, Quad, Monolithic, PSE Controllers for Power over Ethernet

6 _______________________________________________________________________________________

ELECTRICAL CHARACTERISTICS (continued)

AGND

= 32V to 60V, VEE= 0V, VDDto V

DGND

= +3.3V, all voltages are referenced to VEE, unless otherwise noted. Typical values are at

AGND

= +48V, V

DGND

= +48V, VDD= (V

DGND

+ 3.3V), TA= +25°C. Currents are positive when entering the pin and negative other-

wise.) (Note 2)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

DIGITAL INPUTS/OUTPUTS (Referred to DGND)

Digital Input Low V

Digital Input High V

Internal Input Pullup/Pulldown Resistor

O p en- D r ai n O utp ut Low V ol tag eVOLI

Digital Input Leakage I

Open-Drain Leakage I

TIMING

Startup Time t

Fault Time t

Port Turn-Off Time t

Detection Reset Time

Detection Time t

M i d sp an M od e D etecti on D el ay t

Classification Time t

Restart Timer t

Watchdog Clock Period t

ADC PERFORMANCE

Resolution 9 Bits

Range 0.51 V

LSB Step Size 1mV

Integral Nonlinearity (Relative) INL 0.2 1.5 LSB

Turn-On Delay t

EEUVLO

START

FAULT

CLASS

RESTART

DIN

OFF

DET

DMID

DLY

Pullup (pulldown) resistor to VDD (DGND) to set default level

= 15mA 0.4 V

SINK

Input connected to the pull voltage 2 µA

Open-drain high impedance, V

Time during which a current limit set by

is allowed, starts when the GATE_ is

SU_LIM

turned on (Note 9)

Maximum allowed time for an overcurrent condition set by V (Note 9)

Minimum delay between any port turning off, does not apply in case of a reset

Time allowed for the port voltage to reset before detection starts

Maximum time allowed before detection is completed

Time allowed for classification 19 23 ms

Time V 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

Rate of decrement of the watchdog timer 164 ms

must be above the V

AGND

FLT_LIM

after startup

= 3.3V 2 µA

OUT_

EEUVLO

RSTR bits = 00

RSTR bits = 01

RSTR bits = 10

RSTR bits = 11 0

2.4 V

25 50 75 kΩ

50 60 70 ms

0.5 ms

80 90 ms

2.0 2.4 s

24ms

16 x

FAULT

32 x

FAULT

64 x

FAULT

0.9 V

330 ms

MAX5965A/MAX5965B

High-Power, Quad, Monolithic, PSE Controllers

for Power over Ethernet

_______________________________________________________________________________________ 7

ELECTRICAL CHARACTERISTICS (continued)

AGND

= 32V to 60V, VEE= 0V, VDDto V

DGND

= +3.3V, all voltages are referenced to VEE, unless otherwise noted. Typical values are at

AGND

= +48V, V

DGND

= +48V, VDD= (V

DGND

+ 3.3V), TA= +25°C. Currents are positive when entering the pin and negative other-

wise.) (Note 2)

Note 2: Limits to TA= -40°C are guaranteed by design. Note 3: Default values. The charge/discharge currents are programmable through the serial interface (see the

Description

section).

Note 4: Default values. The current-limit thresholds are programmed through the I2C-compatible serial interface (see the

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 (V

- V

DGND

) ≥ 3V and DGND is connected to AGND.

Note 8:t

DISC

can also be programmed through the serial interface (R16H) (see the

section).

Note 9: R

= (V

OUT_2

- V

OUT_1

)/(I

DET_2

- I

DET_1

). V

OUT_1

, V

OUT_2

, I

DET_2

, and I

DET_1

represent the voltage at OUT_ and the cur-

rent 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 I

C serial interface (see the

and Description

section).

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Differential Nonlinearity DNL 0.2 1.5 LSB

Gain Error 3%

ADC Absolute Accuracy V

TIMING CHARACTERISTICS (For 2-Wire Fast Mode)

Serial-Clock Frequency f

Bus Free Time Between a STOP and START Condition

Hold Time for a START Condition

Low Period of the SCL Clock t

High Period of the SCL Clock t

Setup Time for a Repeated START Condition (Sr)

Data Hold Time t

Data in Setup Time t

Rise Time of Both SDA and SCL Signals, Receiving

Fall Time of SDA Transmitting t

Setup Time for STOP Condition t

Capacitive Load for Each Bus Line

Pulse Width of Spike Suppressed

HD, STA

SU, STA

HD, DAT

SU, DAT

SU, STO

= 300mV 295 300 305 LSB

SENSE

SCL

BUF

LOW

HIGH

1.2 µs

0.6 µs

1.2 µs

0.6 µs

100 300 ns

100 ns

20 +

0.1C

20 +

0.1C

0.6 µs

400 kHz

300 ns

400 pF

50 ns

SENSE TRIP VOLTAGE

vs. INPUT VOLTAGE

MAX5965A toc09

AGND

- VEE (V)

SENSE TRIP VOLTAGE (mV)

565236 40 44 48

185.5

186.0

186.5

187.0

187.5

188.0

188.5

189.0

185.0 32 60

MAX5965A/MAX5965B

High-Power, Quad, Monolithic, PSE Controllers for Power over Ethernet

8 _______________________________________________________________________________________

Typical Operating Characteristics

(VEE= -48V, VDD= +3.3V, V

AUTO

= V

AGND

= V

DGND

= 0V, RESET = SHD_ = unconnected, R

SENSE

= 0.5Ω, IVEE = 00, ICUT = 000,

= +25°C, all registers = default setting, unless otherwise noted.)

ANALOG SUPPLY CURRENT

vs. INPUT VOLTAGE

5.5 MEASURED AT AGND

5.4

5.3

5.2

5.1

5.0

4.9

4.8

SUPPLY CURRENT (mA)

4.7

4.6

4.5

32 60

- VEE (V)

AGND

130

125

120

115

110

SUPPLY CURRENT (FA)

105

100

DIGITAL SUPPLY CURRENT

vs. DIGITAL SUPPLY VOLTAGE

MEASURED AT V

2.4 3.6

SUPPLY VOLTAGE (V)

3.43.23.02.82.6

565244 484036

MAX5965A toc01

MAX5965A toc04

5.5

5.4

5.3

5.2

5.1

5.0

4.9

4.8

SUPPLY CURRENT (mA)

4.7

4.6

4.5

-40 85

30.0

29.5

29.0

28.5

28.0

UNDERVOLTAGE LOCKOUT (V)

27.5

27.0

-40 85

ANALOG SUPPLY CURRENT

vs. TEMPERATURE

VEE = -60V VEE = -48V

VEE = -32V

603510-15

TEMPERATURE (NC)

VEE UNDERVOLTAGE LOCKOUT

vs. TEMPERATURE

603510-15

TEMPERATURE (NC)

130

125

MAX5965A toc02

120

115

110

SUPPLY CURRENT (FA)

105

100

10.10

10.08

MAX5965A toc05

10.06

10.04

10.02

10.00

9.98

GATE OVERDRIVE (V)

9.96

9.94

9.92

9.90

DIGITAL SUPPLY CURRENT

vs. TEMPERATURE

MEASURED AT V

-40 85

VDD = 3.6V

VDD = 3.3V

VDD = 2.4V

TEMPERATURE (NC)

GATE OVERDRIVE

vs. INPUT VOLTAGE

32 60

- VEE (V)

AGND

MAX5965A toc03

603510-15

MAX5965A toc06

565244 484036

10.20

10.15

10.10

10.05

10.00

9.95

GATE OVERDRIVE (V)

9.90

9.85

9.80

-40 85

GATE OVERDRIVE

vs. TEMPERATURE

TEMPERATURE (NC)

SENSE TRIP VOLTAGE

vs. TEMPERATURE

196

MAX5965A toc07

192

188

SENSE TRIP VOLTAGE (mV)

184

180

6035-15 10

-40 85 TEMPERATURE (NC)

603510-15

MAX5965A toc08

MAX5965A/MAX5965B

High-Power, Quad, Monolithic, PSE Controllers

for Power over Ethernet

_______________________________________________________________________________________ 9

Typical Operating Characteristics (continued)

(VEE= -48V, VDD= +3.3V, V

AUTO

= V

AGND

= V

DGND

= 0V, RESET = SHD_ = unconnected, R

SENSE

= 0.5Ω, IVEE = 00, ICUT = 000,

= +25°C, all registers = default setting, unless otherwise noted.)

FOLDBACK CURRENT-LIMIT THRESHOLD

vs. OUTPUT VOLTAGE

300

250

200

(mV)

150

- V

SENSE

100

- VEE (V)

OUT

OVERCURRENT TIMEOUT

LOAD

5040302010

= 240Ω TO 57Ω)

MAX5965A toc10

MAX5965A toc12

FOLDBACK CURRENT-LIMIT THRESHOLD

500

450

400

350

(mV)

300

250

- V

200

SENSE

150

100

(AGND - V 50V/div 0V

OUT

)

vs. OUTPUT VOLTAGE

ICUT = 001

- VEE (V)

OUT

DC LOAD DISCONNECT THRESHOLD

vs. TEMPERATURE

MAX5965A toc10A

5040302010

DC LOAD DISCONNECT THRESHOLD (mV)

-40 85

OVERCURRENT RESPONSE WAVEFORM

(MAX5965AUAX) (R

= 240Ω TO 57Ω)

LOAD

MAX5965A toc13

TEMPERATURE (NC)

(AGND - V 50V/div 0V

OUT

MAX5965A toc11

603510-15

)

20ms/div

SHORT-CIRCUIT RESPONSE TIME

20ms/div

MAX5965A toc14

OUT

200mA/div

GATE_

10V/div

INT 5V/div

(AGND - V 20V/div

OUT

200mA/div

GATE_

10V/div

OUT

200mA/div

400μs/div

SHORT-CIRCUIT RESPONSE TIME

)

4μs/div

MAX5965A toc15

GATE 10V/div

INT 2V/div

(AGND - V 20V/div

OUT

10A/div

130mA

GATE_

10V/div

OUT

)

MAX5965A/MAX5965B

High-Power, Quad, Monolithic, PSE Controllers for Power over Ethernet

10 ______________________________________________________________________________________

Typical Operating Characteristics (continued)

(VEE= -48V, VDD= +3.3V, V

AUTO

= V

AGND

= V

DGND

= 0V, RESET = SHD_ = unconnected, R

SENSE

= 0.5Ω, IVEE = 00, ICUT = 000,

= +25°C, all registers = default setting, unless otherwise noted.)

ZERO-CURRENT DETECTION WAVEFORM

MAX5965A toc17

100ms/div

INT 2V/div

OUT

200mA/div

GATE_

10V/div

(AGND - V

OUT

)

20V/div

OVERCURRENT RESTART DELAY

MAX5965A toc18

400ms/div

OUT

200mA/div

GATE_

10V/div

(AGND - V

OUT

)

20V/div

DETECTION WITH INVALID PD (15kΩ)

MAX5965A toc21

100ms/div

OUT

1mA/div

(AGND - V

OUT

)

5V/div

RESET TO OUT TURN-OFF DELAY

MAX5965A toc16

RESET 2V/div

OUT

200mA/div 0A

GATE

5V/div

STARTUP WITH VALID PD

(25kI AND 0.1µF)

MAX5965A toc19

- V

AGND

20V/div

OUT

100mA/div

OUT

DETECTION WITH INVALID PD

(25kI AND 10µF)

MAX5965A toc20

- V

AGND

OUT

20V/div

OUT

1mA/div

GATE

10V/div V

GATE

5V/div

MAX5965A/MAX5965B

High-Power, Quad, Monolithic, PSE Controllers

for Power over Ethernet

______________________________________________________________________________________ 11

Typical Operating Characteristics (continued)

(VEE= -48V, VDD= +3.3V, V

AUTO

= V

AGND

= V

DGND

= 0V, RESET = SHD_ = unconnected, R

SENSE

= 0.5Ω, IVEE = 00, ICUT = 000,

= +25°C, all registers = default setting, unless otherwise noted.)

DETECTION WITH INVALID PD (33kΩ)

DETECTION WITH MIDSPAN MODE

WITH INVALID PD (15kΩ)

100ms/div

MAX5965A toc22

MAX5965A toc24

(AGND - V 5V/div

OUT

1mA/div

(AGND - V 5V/div

OUT

)

STARTUP IN MIDSPAN MODE

WITH VALID PD (25kI AND 0.1µF)

DETECTION WITH MIDSPAN MODE

WITH INVALID PD (33kΩ)

MAX5965A toc23

MAX5965A toc25

AGND

20V/div

OUT

100mA/div

GATE

5V/div

(AGND - V 5V/div

- V

OUT

)

OUT

400ms/div

OUT

1mA/div

GATE_

10V/div

400ms/div

OUT

1mA/div

GATE_

10V/div

DETECTION WITH INVALID PD (OPEN CIRCUIT,

OUTPUT SHORTED

MAX5965A toc26

AGND

5V/div

OUT

1mA/div

GATE

10V/div

- V

OUT

USING TYPICAL OPERATING CIRCUIT 1)

40ms/div

MAX5965A toc27

(AGND - V 5V/div

OUT

1mA/div

GATE_

10V/div

OUT

)

MAX5965A/MAX5965B

High-Power, Quad, Monolithic, PSE Controllers for Power over Ethernet

12 ______________________________________________________________________________________

Typical Operating Characteristics (continued)

(VEE= -48V, VDD= +3.3V, V

AUTO

= V

AGND

= V

DGND

= 0V, RESET = SHD_ = unconnected, R

SENSE

= 0.5Ω, IVEE = 00, ICUT = 000,

= +25°C, all registers = default setting, unless otherwise noted.)

Pin Description

DETECTION WITH INVALID PD (OPEN CIRCUIT,

USING TYPICAL OPERATING CIRCUIT 2)

MAX5965A toc28

STARTUP WITH DIFFERENT

PD CLASSES

MAX5965A toc29

(AGND - V

40ms/div

5V/div

OUT

1mA/div

GATE_

10V/div

OUT

)

2-EVENT CLASSIFICATION

WITH A CLASS 4 PD

MAX5965A toc30

AGND

5V/div

OUT

20mA/div

GATE

10V/div

- V

AGND

OUT

5V/div

CLASS 5

CLASS 4 CLASS 3 CLASS 2 CLASS 1

- V

OUT

20mA/div

PIN NAME FUNCTION

Hardware Reset. Pull RESET low for at least 300µs to reset the device. All internal registers reset to their

1 RESET

2 MIDSPAN

3 INT

4 SCL Serial Interface Clock Line Input

5 SDAOUT

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 V

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 V

to set midspan operation. The MIDSPAN value

DIG

latches after the device is powered up or reset (see the PD Detection section).

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).

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, I

C-compatible system.

MAX5965A/MAX5965B

High-Power, Quad, Monolithic, PSE Controllers

for Power over Ethernet

______________________________________________________________________________________ 13

Pin Description (continued)

PIN NAME FUNCTION

6 SDAIN

7–10 A3–A0

11–14 DET1–DET4

15 DGND Digital Ground. Connect to digital ground.

16 V

17– 20 SHD1–SHD4

21 AGND Analog Ground. Connect to the high-side analog supply.

22, 25,

29, 32

23, 26,

30, 33

SENSE4, SENSE3, SENSE2,

SENSE1

GATE4, GATE3, GATE2,

GATE1

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, I

Address Bits. A3–A0 form the lower part of the device’s address. Address inputs default high with an internal 50kΩ pullup resistor to V its UVLO threshold or after a reset. The 3 MSBs of the address are set to 010.

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).

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 V a 50kΩ resistor.

MOSFET Source Current-Sense Negative Inputs. Connect to the source of the power MOSFET and connect a current-sense resistor between SENSE_ and V

Port_ MOSFET Gate Drivers. Connect GATE_ to the gate of the external MOSFET (see the Typical Operating Circuits).

. The address values latch when VDD or VEE ramps up and exceeds

C-compatible system.

with

(see the Typical Operating Circuits).

24, 27,

31, 34

OUT4, OUT3,

OUT2, OUT1

28 V

35 AUTO

36 OSC

MOSFET Drain-Output Voltage Senses. Connect OUT_ to the power MOSFET drain through a resistor (100Ω to 100kΩ). The low leakage at OUT_ limits the drop across the resistor to less than 100mV (see the 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 V

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 V Software commands can take the MAX5965A/MAX5965B out of AUTO while AUTO is high.

Oscillator Input. AC-disconnect detection function uses OSC. Connect a 100Hz ±10%, 2V 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.

or VEE ramps up and exceeds its UVLO threshold or when the device resets.

±5%, +1.2V

P-P

MAX5965A/MAX5965B

High-Power, Quad, Monolithic, PSE Controllers for Power over Ethernet

14 ______________________________________________________________________________________

Functional Diagram

SHD_

DGNDOSC_INSCL SDAIN SDAOUT

THREE-WIRE

SERIAL

PORT

INTERFACE

AUTO

MIDSPAN

RESET

INT

AGND

DGND

CENTRAL LOGIC UNIT

ANALOG

BIAS/

SUPPLY

MONITOR

(CLU)

+10V ANALOG

+5V DIG

VOLTAGE REFERENCES

CURRENT REFERENCES

OSCILLATOR

MONITOR

PORT STATE

MACHINE

(SM)

FILE

AC DISCONNECT

SIGNAL

(ACD)

CURRENT MEASUREMENT

9-BIT

ADC

OPEN CIRCUIT

(OC)

ACD

REFERENCE

CURRENT

A = 3

DETECTION*

LIMIT (ILIM)

VOLTAGE PROBING

AND

CURRENT-LIMIT

CONTROL

DETECTION/

CLASSIFICATION

ACD_ENABLE

PWR_EN

CURRENT

FAST

DISCHARGE

CONTROL

CURRENT-LIMIT

DETECTOR

9-BIT ADC

CONVERTER

CURRENT SENSING

100mA

90μA

MAX

10V

50μA

VOLTAGE SENSING

13V CLAMP

DET_

OUT_

GATE_

SENSE_

OVERCURRENT

(OVC)

MAX5965A/MAX5965B

*AC DETECTION ONLY FOR THE MAX5965B.

4mV

FOLDBACK

CONTROL

212mV182mV

MAX5965A/MAX5965B

High-Power, Quad, Monolithic, PSE Controllers

for Power over Ethernet

______________________________________________________________________________________ 15

Detailed Description

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 I

C-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 (VEEand VDDrise 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 R11[1] high. The status of the MIDSPAN pin is written to R11[1] during power-up or after a reset. MIDSPAN is internally pulled low by a 50kΩ resistor.

MAX5965A/MAX5965B

High-Power, Quad, Monolithic, PSE Controllers for Power over Ethernet

16 ______________________________________________________________________________________

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).

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.

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