Rainbow Electronics MAX5953D User Manual

General Description

The MAX5953A/MAX5953B/MAX5953C/MAX5953D
integrate a complete power IC solution for Powered
Devices (PD) in a Power-Over-Ethernet (PoE) system, in
compliance with the IEEE 802.3af standard. The
MAX5953A/MAX5953B/MAX5953C/MAX5953D provide
the PD with a detection signature, a classification sig­nature, and an integrated isolation switch with program­mable inrush current control. These devices also
integrate a voltage-mode PWM controller with two
power MOSFETs connected in a two-switch voltage­clamped DC-DC converter configuration.

An integrated MOSFET provides PD isolation during
detection and classification. All devices guarantee a
leakage current offset of less than 10µA during the
detection phase. A programmable current limit pre­vents high inrush current during power-on. The devices
feature power-mode undervoltage lockout (UVLO) with
wide hysteresis and long deglitch time to compensate
for twisted-pair-cable resistive drop and to assure
glitch-free transition between detection, classification,
and power-on/-off phases. The MAX5953A/MAX5953C
have an adjustable UVLO threshold with the default
value compliant to the 802.3af standard, while the
MAX5953B/MAX5953D have a lower and fixed UVLO
threshold compatible with some legacy pre-802.3af
power-sourcing equipment (PSE) devices.

The DC-DC converters are operable in either forward or
flyback configurations with a wide input voltage range
from 11V to 76V and up to 15W of output power. The
voltage-clamped power topology enables full recovery
of stored magnetizing and leakage inductive energy for
enhanced efficiency and reliability. When using the
high-side MOSFET, the controller can be configured as
a buck converter. A look-ahead signal for driving sec­ondary-side synchronous rectifiers can be used to
increase efficiency. A wide array of protection features
include UVLO, over-temperature shutdown, and short­circuit protection with hiccup current limit for enhanced
performance and reliability. Operation up to 500kHz
allows for smaller external magnetics and capacitors.

The MAX5953A/MAX5953B/MAX5953C/MAX5953D are
available in a high-power (2.22W), 7mm x 7mm ther­mally enhanced thin QFN package.

Features

♦ Powered Device Interface

Fully Integrated IEEE 802.3af-Compliant PD

Interface

PD Detection and Programmable Classification

Signatures

Less than 10µA Leakage Current Offset During

Detection

Integrated MOSFET for Isolation and Inrush

Current Limiting

Gate Output Allows External Control of the

Internal Isolation MOSFET
Programmable Inrush Current Control
Programmable Undervoltage Lockout

(MAX5953A/MAX5953C)

♦ DC-DC Converter

Clamped, Two-Switch Power IC for High

Efficiency
Integrated High-Voltage 0.4Ω Power MOSFETs

Up to 15W Output Power
Bias Voltage Regulator with Automatic High-

Voltage Supply Turn-Off
11V to 76V Wide Input Voltage Range
Feed-Forward Voltage-Mode Control for Fast

Input Transient Rejection
Programmable Undervoltage Lockout
Overtemperature Shutdown
Indefinite Short-Circuit Protection with

Programmable Fault Integration
Integrated Look-Ahead Signal for Secondary-

Side Synchronous Rectification
> 90% Efficiency with Synchronous

Rectification
Up to 500kHz Switching Frequency

♦ High-Power (2.22W), 7mm x 7mm Thermally

Enhanced Lead-Free Thin QFN Package

MAX5953A/MAX5953B/MAX5953C/MAX5953D

IEEE 802.3af PD Interface and PWM Controllers

with Integrated Power MOSFETs

________________________________________________________________ Maxim Integrated Products 1

PART PIN-PACKAGE PKG CODE

MAX5953AUTM+* 48 TQFN T4877-6

MAX5953BUTM+ 48 TQFN T4877-6

MAX5953CUTM+* 48 TQFN T4877-6

MAX5953DUTM+* 48 TQFN T4877-6

Ordering Information

19-3945; Rev 0; 1/06

For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.

Operating junction temperature range is 0°C to +125°C.

+Denotes lead-free package.
*Future product—contact factory for availability.

Pin Configuration and Typical Operating Circuit appear at
end of data sheet.

IEEE 802.3af Powered
Devices

IP Phones

Wireless Access Nodes

Internet Appliances

Security Cameras

Computer Telephony

Applications

MAX5953A/MAX5953B/MAX5953C/MAX5953D

IEEE 802.3af PD Interface and PWM Controllers
with Integrated Power MOSFETs

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(VIN= (V+ - VEE) = 48V, GATE = PGOOD = PGOOD = unconnected, GND = OUT, HVIN = V+, UVLO = VEE, TJ= 0°C to +125°C, unless

otherwise noted. Typical values are at T

J

= +25°C. All voltages are referenced to VEE, unless otherwise noted.) (Note 1)

Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.

V+ to VEE................................................................-0.3V to +90V

OUT, PGOOD, PGOOD to V

EE

.....................-0.3V to (V+ + 0.3V)

RCLASS, GATE to V

EE

...........................................-0.3V to +12V

UVLO to V

EE

............................................................ -0.3V to +8V

PGOOD to OUT ........................................... -0.3V to (V+ + 0.3V)

HVIN, INBIAS, DRNH, XFRMRH,

XFRMRL to GND.................................................-0.3V to +80V

BST to GND ........................................................... -0.3V to +95V

BST to XFRMRH .................................................... -0.3V to +12V

PGND to GND .......................................................-0.3V to +0.3V

DCUVLO, RAMP, CSS, OPTO, FLTINT, RCFF,

RTCT to GND..................................................... -0.3V to +12V

SRC, CS to GND...................................................... -0.3V to +6V

REGOUT, DRVIN to GND .......................................-0.3V to +12V

REGOUT to HVIN .................................................. -80V to +0.3V

REGOUT to INBIAS ............................................... -80V to +0.3V

PPWM to GND....................................-0.3V to (V

REGOUT

+ 0.3V)

Maximum Input/Output Current (Continuous)

OUT to V

EE

....................................................................500mA

V+, RCLASS to V

EE

.........................................................70mA

UVLO, PGOOD, PGOOD to V

EE

.....................................20mA

GATE to V

EE

....................................................................80mA

REGOUT to GND ............................................................50mA

DRNH, XFRMRH, XFRMRL, SRC to GND (Average),

T

J

= +125°C..................................................................0.9A

PPWM to GND ..............................................................±20mA

Continuous Power Dissipation* (T

A

= +70°C)
48-Pin TQFN 7mm X 7mm

(derate 27.8mW/°C above +70°C).............................2222mW

θ

JA

................................................................................36°C/W

Operating Ambient Temperature Range ................0°C to +85°C

Operating Junction Temperature Range ..............0°C to +125°C

Junction Temperature......................................................+150°C

Storage Temperature Range .............................-60°C to +150°C

Lead Temperature (soldering, 10s) .................................+300°C

PARAMETER

CONDITIONS

UNITS

POWERED DEVICE (PD) INTERFACE

DETECTION MODE

Input Offset Current I

OFFSET

VIN = 1.4V to 10.1V (Note 2) 10 µA

Effective Differential Input
Resistance (Note 3)

dR V

IN

= 1.4V, up to 10.1V with 1V step

kΩ

CLASSIFICATION MODE

Classification Current Turn-Off
Threshold

VIN rising (Note 4)

V

Class 0, R

RCLASS

= 10kΩ 02

Class 1, R

RCLASS

= 732Ω

Class 2, R

RCLASS

= 392Ω

Class 3, R

RCLASS

= 255Ω

Classification Current I

CLASS

VIN = 12.6V
to 20V,
R

DISC

=

25.5kΩ

Class 4, R

RCLASS

= 178Ω

mA

POWER MODE

Operating Supply Voltage V

IN

VIN = (V+ - VEE)67V

Operating Supply Current I

IN

Measure at V+, not including R

DISC

,

GATE = V

EE

, HVIN = GND = OUT

0.4 1 mA

MAX5953A/MAX5953C

Default Power Turn-On Voltage

V

IN

increasing

MAX5953B/MAX5953D

V

Default Power Turn-Off Voltage

VIN decreasing, MAX5953A/MAX5953C 30 V

*As per JEDEC 51 standard.

SYMBOL

(Notes 5, 6)

V

TH,CLASS

V

UVLO, ON

V

UVLO,OFF

MIN TYP MAX

550

20.8 21.8 22.5

9.17 11.83

17.29 19.71

26.45 29.55

36.6 41.4

37.4 38.6 40.2

34.3 35.4 36.9

MAX5953A/MAX5953B/MAX5953C/MAX5953D

IEEE 802.3af PD Interface and PWM Controllers

with Integrated Power MOSFETs

_______________________________________________________________________________________ 3

ELECTRICAL CHARACTERISTICS (continued)

(VIN= (V+ - VEE) = 48V, GATE = PGOOD = PGOOD = unconnected, GND = OUT, HVIN = V+, UVLO = VEE, TJ= 0°C to +125°C, unless
otherwise noted. Typical values are at T

J

= +25°C. All voltages are referenced to VEE, unless otherwise noted.) (Note 1)

PARAMETER

SYMBOL

CONDITIONS

MIN

TYP

MAX

UNITS

MAX5953A/MAX5953C 7.1

Default Power Turn-On/Off
Hysteresis Voltage

MAX5953B/MAX5953D 4

V

External UVLO Programming
Range

V

IN,EX

MAX5953A/MAX5953C only (Note 7) 12 67 V

UVLO External Reference
Voltage

V

UVLO

increasing

V

UVLO External Reference
Voltage Hysteresis

Ratio to V

REF, UVLO

20

%

UVLO Bias Current I

IN,UVLO

V

UVLO

= 2.460V

µA

UVLO Input Ground-Sense
Threshold

(Note 8) 50 440 mV

UVLO Input Ground-Sense Glitch
Rejection

7µs

Power Turn-Off Voltage,
Undervoltage Lockout Deglitch
Time

t

OFF_DLY

VIN, V

UVLO

falling (Note 9)

ms

Isolation Switch n-Channel
MOSFET On-Resistance

R

ON,ISO

Output current = 300mA, V

GATE

= 5.6V,

measured between OUT and V

EE

0.6 1.5 Ω

Isolation Switch n-Channel
MOSFET Off-Threshold Voltage

V

GSTH

V

GATE

- VEE, OUT = V+,

output current < 1µA

0.5 V

GATE Pulldown Switch
Resistance

R

G

Power-off mode, VIN = +12V 38 80 Ω

GATE Charging Current I

GATE

V

GATE

= 2V 4.5 10

µA

GATE High Voltage V

GATE

I

GATE

= 1µA

V

V

OUT

- VEE decreasing, V

GATE

= 5.75V

V

PGOOD Assertion V

OUT

Threshold (Note 10)

V

OUTEN

Hysteresis 70 mV

V

GATE

- VEE increasing

V

PGOOD, PGOOD Assertion
V

GATE

Threshold

V

GSEN

Hysteresis 80 mV

PGOOD, PGOOD Output Low
Voltage

I

SINK

= 2mA, V

OUT

≤ (V+ - 5V) (Note 11) 0.2 V

PGOOD Leakage Current

1µA

PGOOD Leakage Current

GATE = V

EE

, PGOOD - VEE = 67V

(Note 11)

1µA

V

HYST,UVLO

V

REF,UVLO

V

HYST,UVLO

2.400 2.460 2.522

19.2

-1.5 +1.5

V

TH,G,UVLO

0.32

5.59 5.76 5.93

1.16 1.23 1.31

20.9

16.5

V

OL,PGOOD

GATE = high, V+ - V

OUT

= 67V (Note 11)

4.62 4.76 4.91

MAX5953A/MAX5953B/MAX5953C/MAX5953D

IEEE 802.3af PD Interface and PWM Controllers
with Integrated Power MOSFETs

4 _______________________________________________________________________________________

ELECTRICAL CHARACTERISTICS (DC-DC Controller)

(All voltages referenced to GND, unless otherwise noted. V

HVIN

= +48V, C

INBIAS

= 1µF, C

REGOUT

= 2.2µF, R

RTCT

= 25kΩ, C

RTCT

=

100pF, C

BST

= 0.22µF, V

CSS

= V

CS

= 0V, V

RAMP

= V

DCUVLO

= 3V, TJ= 0°C to +125°C, unless otherwise noted. Typical values are at

T

J

= +25°C, unless otherwise noted.) (Note 1)

PARAMETER SYMBOL CONDITIONS

MIN

TYP

MAX

UNITS

Input Supply Range V

HVIN

11 76 V

OSCILLATOR (RTCT)

PWM Frequency f

S

250 kHz

Maximum PWM Duty Cycle D

MAX

47 %

Maximum RTCT Frequency f

RTCTMAX

(Note 12) 1 MHz

RTCT Peak Trip Level V

TH,RTCT

0.51 x V

REGOUT

V

RTCT Valley Trip Level V

TL,RTCT

1V

RTCT Input Bias Current I

IN,RTCT

±1 µA

RTCT Discharge MOSFET
R

DS(ON)

R

DIS,RTCT

Sinking 50mA 35 85 Ω

RTCT Discharge Pulse Width 50 ns

LOOK-AHEAD LOGIC (PPWM)

PPWM to Output Propagation
Delay

t

PPWM

V

PPWM

rising to V

XFRMRL

falling 110 ns

PPWM Output High V

OH,PPWM

Sourcing 2mA 7.0

V

PPWM Output Low V

OL,PPWM

Sinking 2mA 0.2 V

PWM COMPARATOR (OPTO, RAMP, RCFF)

Common-Mode Input Range V

CM_PWM

0 5.5 V

Input Offset Voltage 10 mV

Input Bias Current -2 +2 µA

RAMP to XFRMRL Propagation
Delay

From V

RAMP

(50mV overdrive) rising to

V

XFRMRL

rising

100 ns

Minimum OPTO Voltage V

CSS

= 0V, OPTO sinking 2mA

V

Minimum RCFF Voltage RCFF sinking 2mA

V

REGOUT LDO (REGOUT)

INBIAS unconnected,
V

HVIN

= 11V to 76V

8.3

9.2

REGOUT Voltage Set Point V

REGOUT

V

INBIAS

= V

HVIN

= 11V to 76V 9.5

V

INBIAS unconnected, V

HVIN

= 15V,

I

REGOUT

= 0 to 30mA

REGOUT Load Regulation

V

INBIAS

= V

HVIN

= 15V,

I

REGOUT

= 0 to 30mA

V

INBIAS unconnected, I

REGOUT

= 30mA

REGOUT Dropout Voltage

V

INBIAS

= V

HVIN

, I

REGOUT

= 30mA

V

REGOUT Undervoltage
Lockout Threshold

REGOUT rising 6.6 7.0 7.4 V

REGOUT Undervoltage

REGOUT falling 0.7 V

t

COMPARATOR

Lockout Threshold Hysteresis

1.47

2.18

8.75

10.6 11.0

11.0

0.25

0.25

1.25

1.25

MAX5953A/MAX5953B/MAX5953C/MAX5953D

IEEE 802.3af PD Interface and PWM Controllers

with Integrated Power MOSFETs

_______________________________________________________________________________________ 5

ELECTRICAL CHARACTERISTICS (DC-DC Controller) (continued)

(All voltages referenced to GND, unless otherwise noted. V

HVIN

= +48V, C

INBIAS

= 1µF, C

REGOUT

= 2.2µF, R

RTCT

= 25kΩ, C

RTCT

=

100pF, C

BST

= 0.22µF, V

CSS

= V

CS

= 0V, V

RAMP

= V

DCUVLO

= 3V, TJ= 0°C to +125°C, unless otherwise noted. Typical values are at

T

J

= +25°C, unless otherwise noted.) (Note 1)

PARAMETER SYMBOL CONDITIONS

MIN

TYP

MAX

UNITS

SOFT-START (CSS)

Soft-Start Current I

CSS

V

CSS

= 0V 33 µA

INTEGRATING FAULT PROTECTION

FLTINT Source Current I

FLTINT

80 µA

FLTINT Trip Point V

FLTINT

rising 2.7 V

FLTINT Hysteresis

V

INTERNAL POWER FETs

On-Resistance

V

DRVIN

= V

BST

= 9V,

V

XFRMRH

= V

SRC

= 0V, IDS = 50mA

0.4 0.8 Ω

Off-State Leakage Current -5

µA

Total Gate Charge Per Power
FET

15 nC

HIGH-SIDE DRIVER

Low to High Latency t

LH-HS

Driver delay until FET VGS reaches 0.9 x
(V

BST

- V

XFRMRH

) and is fully on

80 ns

High to Low Latency t

HL-HS

Driver delay until FET VGS reaches 0.1 x
(V

BST

- V

XFRMRH

) and is fully off

40 ns

Output Drive Voltage V

BST

BST to XFRMRH with high side on 8 V

LOW-SIDE DRIVER

Low to High Latency t

LH-LS

Driver delay until FET VGS reaches 0.9 x
V

DRVIN

and is fully on

80 ns

High to Low Latency t

HL-LS

Driver delay until FET VGS reaches 0.1 x
V

DRVIN

and is fully off

40 ns

CURRENT-LIMIT COMPARATOR (CS)

Current-Limit Threshold
Voltage

V

ILIM

156

mV

Current-Limit Input Bias
Current

I

BILIM

0 < VCS < 0.3V -2 +2 µA

Propagation Delay to XFRMRL

t

dILIM

From VCS rising (10mV overdrive) to
V

XFRMRL

rising

160 ns

BOOST VOLTAGE CIRCUIT (See Figure 9, QB)

Driver Output Delay t

PPWMD

200 ns

One-Shot Pulse Width t

PWQB

300 ns

QB R

DSON

Sinking 20mA 30 60 Ω

THERMAL SHUTDOWN

Shutdown Temperature T

SH

Temperature rising

°C

Thermal Hysteresis T

H

20 °C

R

ON,POWER

140

0.75

+160

+10

172

MAX5953A/MAX5953B/MAX5953C/MAX5953D

IEEE 802.3af PD Interface and PWM Controllers
with Integrated Power MOSFETs

6 _______________________________________________________________________________________

ELECTRICAL CHARACTERISTICS (DC-DC Controller) (continued)

(All voltages referenced to GND, unless otherwise noted. V

HVIN

= +48V, C

INBIAS

= 1µF, C

REGOUT

= 2.2µF, R

RTCT

= 25kΩ, C

RTCT

=

100pF, C

BST

= 0.22µF, V

CSS

= V

CS

= 0V, V

RAMP

= V

DCUVLO

= 3V, TJ= 0°C to +125°C, unless otherwise noted. Typical values are at

T

J

= +25°C, unless otherwise noted.) (Note 1)

PARAMETER SYMBOL CONDITIONS

UNITS

UNDERVOLTAGE LOCKOUT (DCUVLO)

Threshold Voltage

V

DCUVLO

rising

V

Hysteresis

140 mV

Input Bias Current I

IN,DCUVLOVDCUVLO

= 3V

nA

SUPPLY CURRENT

From V

HVIN

= 11V to 76V,

V

CSS

= 0V, V

INBIAS

= 11V

0.7 1.5

From V

INBIAS

= 11V to 76V,

V

CSS

= 0V, V

HVIN

= 76V

4.4 6.4

Supply Current

From V

HVIN

= 76V, V

OPIO

= 4V 7

mA

Standby Supply Current V

DCUVLO

= 0V 1 mA

Note 1: Limits at 0°C are guaranteed by design, unless otherwise noted.
Note 2: The input offset current is illustrated in Figure 1.
Note 3: Effective differential input resistance is defined as the differential resistance between V+ and V

EE

without any external

resistance.

Note 4: Classification current is turned off whenever the IC is in power mode.
Note 5: See Table 2 in the Classification Mode section. R

DISC

and R

RCLASS

must be 1%, 100ppm or better. I

CLASS

includes the IC

bias current and the current drawn by R

DISC

.

Note 6: See the Thermal Dissipation section.
Note 7: When UVLO is connected to the midpoint of an external resistor-divider with a series resistance of 25.5kΩ (±1%), the turn-

on threshold set point for the power mode is defined by the external resistor-divider. Make sure the voltage on UVLO does
not exceed its maximum rating of 8V when V

IN

is at the maximum voltage.

Note 8: When V

UVLO

is below V

TH,G,UVLO

, the MAX5953A/MAX5953C set the turn-on voltage threshold internally (V

UVLO,ON

).

Note 9: An input voltage or V

UVLO

glitch below their respective thresholds shorter than or equal to t

OFF_DLY

does not cause the
MAX5953A/MAX5953B/MAX5953C/MAX5953D to exit power-on mode (as long as the input voltage remains above an
operable voltage level of 12V).

Note 10: Guaranteed by design, not tested in production for MAX5953B/MAX5953D.
Note 11: PGOOD references to OUT while PGOOD references to V

EE

.

Note 12: Output switching frequency is

1

/2oscillator frequency.

Figure 1. Effective Differential Input Resistance/Offset Current

I

IN

I

INi + 1

I

INi

I

OFFSET

dR

i

1VV

INi

V

INi + 1

I

OFFSET

≅ I

INi

-

V

INi

dR

i

dRi ≅

(V

INi + 1

- V

INi

)

= 1V

(I

INi + 1

- I

INi

)

(I

INi + 1

- I

INi

)

V

IN

MIN TYP MAX

V

REF,DCUVLO

V

HYS,DCUVLO

1.14 1.26 1.38

-100 +100

MAX5953A/MAX5953B/MAX5953C/MAX5953D

IEEE 802.3af PD Interface and PWM Controllers

with Integrated Power MOSFETs

_______________________________________________________________________________________ 7

DETECTION CURRENT

vs. INPUT VOLTAGE

MAX5953A/B/C/D toc01

INPUT VOLTAGE (V)

DETECTION CURRENT (mA)

8642

0.1

0.2

0.3

0.4

0.5

0

010

R

DISC

= 25.5k

Ω

IIN + I

RDISC

CLASSIFICATION CURRENT

vs. INPUT VOLTAGE

MAX5953A/B/C/D toc02

INPUT VOLTAGE (V)

CLASSIFICATION CURRENT (mA)

252015105

5

10

15

20

25

30

35

40

45

50

0

030

CLASS 4

CLASS 3

CLASS 2

CLASS 1

CLASS 0

EFFECTIVE DIFFERENTIAL INPUT
RESISTANCE vs. INPUT CURRENT

MAX5953A/B/C/D toc03

INPUT VOLTAGE (V)

EFFECTIVE DIFFERENTIAL INPUT RESISTANCE (MΩ)

8642

0.5

1.0

1.5

2.0

2.5

3.0

3.5

0

010

INPUT OFFSET CURRENT

vs. INPUT VOLTAGE

MAX5953A/B/C/D toc04

INPUT VOLTAGE (V)

INPUT OFFSET CURRENT (µA)

862 4

-3.5

-3.0

-2.5

-2.0

-1.5

-1.0

-0.5

0

-4.0
010

NORMALIZED UVLO
vs. TEMPERATURE

MAX5953A/B/C/D toc05

TEMPERATURE (°C)

NORMALIZED UVLO

100755025

0.992

0.994

0.996

0.998

1.000

1.002

1.004

1.006

1.008

1.010

0.990
0125

PGOOD OUTPUT LOW VOLTAGE

vs. CURRENT

MAX5953A/B/C/D toc06

I

SINK

(mA)

V

PGOOD

(mV)

15105

50

100

150

200

250

0

020

OUT LEAKAGE CURRENT

vs. TEMPERATURE

MAX5953A/B/C/D toc07

TEMPERATURE (°C)

OUT LEAKAGE CURRENT (nA)

100755025

1

10

100

1000

0.1
0125

V

OUT

= 48V

INRUSH CURRENT CONTROL

(V

IN

= 48V)

MAX5953A/B/C/D toc08

4ms/div

V

OUT

TO
V

EE

50V/div

V

GATE

5V/div

0V

0V

0A

0V

I

INRUSH

100mA/div

PGOOD
50V/div

DCUVLO THRESHOLD

vs. TEMPERATURE

MAX5953A/B/C/D toc09

TEMPERATURE (°C)

V

DCUVLO

(V)

100755025

1.2750

1.2775

1.2800

1.2825

1.2725
0 125

DCUVLO RISING

Typical Operating Characteristics

(VIN= (V+ - VEE) = 48V, GATE = PGOOD = unconnected, GND connected to OUT, HVIN connected to V+, UVLO = VEE, C

INBIAS

= 1µF,

C

REGOUT

= 2.2µF, R

RTCT

= 25kΩ, C

RTCT

= 100pF, C

BST

= 0.22µF, TJ= 0°C to +125°C, unless otherwise noted. Typical values are

at TJ= +25°C. All voltages are referenced to VEE, unless otherwise noted.)

MAX5953A/MAX5953B/MAX5953C/MAX5953D

IEEE 802.3af PD Interface and PWM Controllers
with Integrated Power MOSFETs

8 _______________________________________________________________________________________

Typical Operating Characteristics (continued)

(VIN= (V+ - VEE) = 48V, GATE = PGOOD = unconnected, GND connected to OUT, HVIN connected to V+, UVLO = VEE, C

INBIAS

= 1µF,

C

REGOUT

= 2.2µF, R

RTCT

= 25kΩ, C

RTCT

= 100pF, C

BST

= 0.22µF, TJ= 0°C to +125°C, unless otherwise noted. Typical values are

at TJ= +25°C. All voltages are referenced to VEE, unless otherwise noted.)

HVIN STANDBY CURRENT

vs. TEMPERATURE

MAX5953A/B/C/D toc10

TEMPERATURE (°C)

STANDBY CURRENT (µA)

100755025

35

70

105

140

175

210

245

280

315

350

385

0

0125

f

HVIN

V

DCUVLO

= 0V

HVIN INPUT CURRENT

vs. TEMPERATURE

MAX5953A/B/C/D toc11

TEMPERATURE (°C)

I

HVIN

(mA)

1007525 50

4.1

4.2

4.3

4.4

4.5

4.6

4.7

4.8

4.0
0125

INBIAS FLOATING
V

HVIN

= 76V

REGOUT = DRVIN

HVIN AND INBIAS INPUT CURRENT

vs. TEMPERATURE

MAX5953A/B/C/D toc12

TEMPERATURE (°C)

INPUT CURRENT (mA)

100755025

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

0

0125

I

INBIAS

I

HVIN

V

HVIN

= V

INBIAS

= 76V

REGOUT VOLTAGE

vs. INPUT VOLTAGE

MAX5953A/B/C/D toc13

V

HIN

(V)

V

REGOUT

(V)

63503724

8.76

8.77

8.78

8.79

8.80

8.81

8.82

8.83

8.84

8.85

8.75
11 76

INBIAS FLOATING
GND = V

EE

REGOUT VOLTAGE

vs. TEMPERATURE

MAX5953A/B/C/D toc14

TEMPERATURE (°C)

V

REGOUT

(V)

100755025

8.72

8.74

8.76

8.78

8.80

8.82

8.84

8.86

8.88

8.90

8.70
0125

V

HVIN

= 48V

INBIAS FLOATING

REGOUT VOLTAGE

vs. LOAD CURRENT

MAX5953A/B/C/D toc15

I

REGOUT

(mA)

V

REGOUT

(V)

252015105

8.70

8.75

8.80

8.85

8.65
030

V

HVIN

= 15V
INBIAS FLOATING
GND = V

EE

REGOUT VOLTAGE

vs. INPUT VOLTAGE

MAX5953A/B/C/D toc16

V

HIN

(V)

V

REGOUT

(V)

63503724

10.62

10.64

10.66

10.68

10.70

10.60
11 76

HVIN = INBIAS
GND = V

EE

REGOUT VOLTAGE

vs. TEMPERATURE

MAX5953A/B/C/D toc17

TEMPERATURE (°C)

V

REGOUT

(V)

100755025

10.66

10.67

10.68

10.69

10.70

10.71

10.72

10.73

10.74

10.75

10.65
0125

V

HVIN

= V

INBIAS

= 48V

REGOUT VOLTAGE

vs. LOAD CURRENT

MAX5953A/B/C/D toc18

I

REGOUT

(mA)

V

REGOUT

(V)

252015105

10.55

10.60

10.65

10.70

10.75

10.50
030

V

HVIN

= V

INBIAS

= 15V

GND = V

EE

MAX5953A/MAX5953B/MAX5953C/MAX5953D

IEEE 802.3af PD Interface and PWM Controllers

with Integrated Power MOSFETs

_______________________________________________________________________________________ 9

REGOUT UVLO VOLTAGE

vs. TEMPERATURE

MAX5953A/B/C/D toc19

TEMPERATURE (°C)

REGOUT UVLO VOLTAGE (V)

100755025

6.2

6.4

6.6

6.8

7.0

7.2

7.4

6.0
0125

RISING

FALLING

OPERATING FREQUENCY

vs. TEMPERATURE

MAX5953A/B/C/D toc20

TEMPERATURE (°C)

OPERATING FREQUENCY (kHz)

1007525 50

250

300

350

400

450

500

550

600

200

0125

R

RTCT

= 12k

Ω

C

RTCT

= 100pF

R

RTCT

= 24.3k

Ω

C

RTCT

= 100pF

SOFT-START CURRENT

vs. TEMPERATURE

MAX5953A/B/C/D toc21

TEMPERATURE (°C)

SOFT-START CURRENT (µA)

100755025

31.5

32.0

32.5

33.0

33.5

34.0

31.0
0125

MINIMUM RCFF AND OPTO LEVELS

vs. TEMPERATURE

MAX5953A/B/C/D toc22

TEMPERATURE (°C)

V

RCFF

(V), V

OPTO

(V)

100755025

1.25

1.50

1.75

2.00

2.25

2.50

2.75

1.00

0125

RCFF

OPTO

CURRENT-LIMIT COMPARATOR

THRESHOLD vs. TEMPERATURE

MAX5953A/B/C/D toc23

TEMPERATURE (°C)

V

REGOUT

(V)

100755025

0.151

0.152

0.153

0.154

0.155

0.156

0.157

0.158

0.159

0.160

0.150
0125

HVIN RISING

PPWM TO XFRMRL SKEW

vs. TEMPERATURE

MAX5953A/B/C/D toc24

TEMPERATURE (°C)

PPWM TO XFRMRL SKEW (ns)

100755025

91

92

93

94

95

96

97

98

99

100

90

0125

FLTINT CURRENT

vs. TEMPERATURE

MAX5953A/B/C/D toc25

TEMPERATURE (°C)

I

FLTINT

(µA)

100755025

76

77

78

79

80

81

82

83

84

85

75

0 125

FLTINT SHUTDOWN VOLTAGE

vs. TEMPERATURE

MAX5953A/B/C/D toc26

TEMPERATURE (°C)

V

FLTINT

(V)

100755025

2.0

2.1

2.2

2.3

2.4

2.5

2.6

2.7

2.8

2.9

1.9
0125

RISING

FALLING

POWER MOSFETS R

DS(ON)

vs. TEMPERATURE

MAX5953A/B/C/D toc27

TEMPERATURE (°C)

R

DS(ON)

(Ω)

100755025

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0

0125

Typical Operating Characteristics (continued)

(VIN= (V+ - VEE) = 48V, GATE = PGOOD = unconnected, GND connected to OUT, HVIN connected to V+, UVLO = VEE, C

INBIAS

= 1µF,

C

REGOUT

= 2.2µF, R

RTCT

= 25kΩ, C

RTCT

= 100pF, C

BST

= 0.22µF, TJ= 0°C to +125°C, unless otherwise noted. Typical values are

at TJ= +25°C. All voltages are referenced to VEE, unless otherwise noted.)