max5922aeuit Maxim Integrated Products, Inc., max5922aeuit Datasheet

max5922aeuit

Manufacturer Part Number

max5922aeuit

Description

Max5922 +48v, Single-port Network Power Switch For Power-over-lan

Manufacturer

Maxim Integrated Products, Inc.

Datasheet

1.MAX5922AEUIT.pdf (21 pages)

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The MAX5922A/B/C is a single-port network power con-

troller with an integrated power MOSFET, operating from

a +32V to +60V supply rail. The device is specifically

designed for power-sourcing equipment (PSE) in power-

over-LAN applications and is fully compliant to the IEEE

802.3af standard. The MAX5922 provides power devices

(PD) discovery, classification, current limit, and other nec-

essary functions for an IEEE 802.3af compliant PSE.

The MAX5922 is suitable for PSE function in both

switch/router systems where the power is delivered to the

load through the signal pairs, and in midspan systems

where the power is delivered to the load through the

spare pairs. In midspan mode, a detection collision

avoidance circuit (MAX5922A/C only) provides the nec-

essary back-off timing to prevent fault detections that

happen when two different PSEs try to detect and

power the same PD. The MAX5922B/C have a detec-

tion disable input that can be connected high to disable

the detection/classification functions or connected low

to enable them.

The MAX5922 features a programmable undervoltage

lockout (UVLO) that keeps the device in shutdown until

the input voltage exceeds a certain threshold, set to 38V

(MAX5922A) or 28V (MAX5922B/C) internally. After suc-

cessfully discovering and classifying a PD, the MAX5922

enters startup mode. During startup, the MAX5922 limits

the output voltage and current slew rate to minimize EMI

(electromagnetic interference). The MAX5922 has an inte-

grated 0.45Ω N-channel power MOSFET that provides

efficient operation and simplified system design. The

MAX5922 monitors and provides current-limit protection

to the load at all times. The current limit is programmable

using an external current-sensing resistor. The MAX5922

features current-limit foldback and duty-cycle limit to

ensure robust operation during load-fault and short-circuit

conditions. Fault management allows the part to either

latch-off or autorestart after a fault.

The MAX5922 provides POK, ZC, and FAULT status sig-

nals to indicate output power is good, zero-current fault,

and other faults (overcurrent, overtemperature), respec-

tively. The MAX5922 is available in a 28-pin TSSOP pack-

age and is rated over the extended -40°C to +85°C

temperature range.

19-2708; Rev 0; 4/03

Typical Application Circuits, Selector Guide, and Pin

Configuration appear at end of data sheet.

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.

+48V, Single-Port Network Power Switch

________________________________________________________________ Maxim Integrated Products

General Description

o IEEE 802.3af Compliant

o +32V to +60V Wide Operating Input Range

o 0.45Ω Integrated Power Switch

o Power Device (PD) Detection and Classification

o 100µA PD Leakage Detection Tolerant

o Programmable Current Limit

o Zero-Current Detection with Status Output

o Detection Collision Avoidance Option for Midspan

o Input Logic Signals Compatible with 1.8V to 5V

o Separate Analog and Digital Grounds with Up to

o Power-Good Status Output

o Overcurrent and Overtemperature Protection with

o Current-Limit Foldback with Timeout and Duty-

o Latch or Autorestart Fault Management

MAX5922AEUI

MAX5922BEUI

MAX5922CEUI

Power-Sourcing Equipment (PSE)

Power-Over-LAN/Power-Over-MDI

Computer Telephony

Single-Port Power Injector/Adapter

Midspan Power Injector

Switches/Routers with In-Line Power

Application

CMOS Logic

±4V Offset

Status Outputs

Cycle Control

(Media-Dependent Interface)

PART

For Power-Over-LAN

-40°C to +85°C

TEMP RANGE

Ordering Information

Applications

PIN-PACKAGE

28 TSSOP

Features

Related parts for max5922aeuit

max5922aeuit Summary of contents

Page 1

Rev 0; 4/03 +48V, Single-Port Network Power Switch General Description The MAX5922A/B single-port network power con- troller with an integrated power MOSFET, operating from a +32V to +60V supply rail. The device is specifically designed for power-sourcing ...

Page 2

Single-Port Network Power Switch For Power-Over-LAN ABSOLUTE MAXIMUM RATINGS (All voltages with respect to AGND_S, unless otherwise noted.) IN ............................................................................-0.3V to +76V UVLO ........................................................................-0. DGND ..........................................................-0.3V to +6V DIG OUT .......................................................-0. DRAIN ..........................................................-0.3V ...

Page 3

Single-Port Network Power Switch ELECTRICAL CHARACTERISTICS (continued 48V 3.3V, AGND_S = AGND = DGND = 0V DIG = 18.2kΩ ±1 -40°C to +85°C, unless otherwise noted. Typical values are at T ...

Page 4

Single-Port Network Power Switch For Power-Over-LAN ELECTRICAL CHARACTERISTICS (continued 48V 3.3V, AGND_S = AGND = DGND = 0V DIG = 18.2kΩ ±1 -40°C to +85°C, unless otherwise noted. Typical values are ...

Page 5

Single-Port Network Power Switch (MAX5922A 48V EN, LATCH, CLASS, and ZC_EN = 3.3V, DCA, AGND_S = AGND = DGND = 0V DIG UVLO floating 150kΩ 18.2kΩ, T RCL RDT ...

Page 6

Single-Port Network Power Switch For Power-Over-LAN (MAX5922A 48V EN, LATCH, CLASS, and ZC_EN = 3.3V, DCA, AGND_S = AGND = DGND = 0V, R DIG IN UVLO floating 150kΩ 18.2kΩ, T ...

Page 7

Single-Port Network Power Switch (MAX5922A 48V EN, LATCH, CLASS, and ZC_EN = 3.3V, DCA, AGND_S = AGND = DGND = 0V DIG UVLO floating 150kΩ 18.2kΩ, T RCL RDT ...

Page 8

Single-Port Network Power Switch For Power-Over-LAN (MAX5922A 48V EN, LATCH, CLASS, and ZC_EN = 3.3V, DCA, AGND_S = AGND = DGND = 0V, R DIG IN UVLO floating 150kΩ 18.2kΩ, T ...

Page 9

Single-Port Network Power Switch (MAX5922A 48V EN, LATCH, CLASS, and ZC_EN = 3.3V, DCA, AGND_S = AGND = DGND = 0V DIG UVLO floating 150kΩ 18.2kΩ, T RCL RDT ...

Page 10

Single-Port Network Power Switch For Power-Over-LAN PIN NAME Analog Ground. This is the return of analog power input. AGND can vary ±4V from DGND. AGND and * AGND DGND must be connected together at a single point in the ...

Page 11

Single-Port Network Power Switch PIN NAME Zero-Current-Detection Enable Logic Input. Referenced to DGND. Connect ZC_EN to a logic high to 21 ZC_EN enable the zero-current detection circuitry. Connect ZC_EN to a logic low to disable this function. ON/OFF Control-Logic ...

Page 12

Single-Port Network Power Switch For Power-Over-LAN Detailed Description The MAX5922 is a single-port network power controller with an integrated power MOSFET, operating from a +32V to +60V supply rail. The device is specifically designed for PSE in power-over-LAN applications ...

Page 13

Single-Port Network Power Switch POWER-ON RESET Y N LATCH = HIBH Y SWITCH SHUTOFF FAULT = LOW SWITCH SHUT-OFF ZC = LOW RESET t ZCDEL 350ms? ZCDEL V INCREMENT t ZCDEL ...

Page 14

Single-Port Network Power Switch For Power-Over-LAN INTERNAL TO MAX5922 I = 1.5mA MAX V PROBE_VOLTAGE Figure 3. PSE Detection Source RESET POWER- LATCH = HIGH? SWITCH SHUT-OFF FAULT = LOW SWITCH SHUT-OFF ZC = LOW RESET t ...

Page 15

Single-Port Network Power Switch UVLO OUT DET1 88ms Figure 5. PD Detection with an Invalid PD Signature Table 2. PD Classification Threshold Limits SENSED CURRENT (mA) CL2 0 above ...

Page 16

Single-Port Network Power Switch For Power-Over-LAN +48V +17.5V +8V +4V V CROSSES UVLO Figure 6. Startup Sequence output voltage slew rate at the OUT pin to dV 100V/ms (max) and the output-current slew rate out of ...

Page 17

Single-Port Network Power Switch V = 32V TO 60V MAX5922 UVLO R2 AGND_S Figure 7. Setting Undervoltage Lockout with an External Resistive-Divider V is the input supply for the internal logic circuitry. DIG The logic input ...

Page 18

Single-Port Network Power Switch For Power-Over-LAN This overcurrent timeout enables the MAX5922 to operate in a periodic overcurrent condition without causing a fault (see Figure 9). Power-OK (POK) POK goes open-drain t POK_HIGH rises to within V (0.75V) from ...

Page 19

Single-Port Network Power Switch PART PIN-PACKAGE MAX5922AEUI 28 TSSOP MAX5922BEUI 28 TSSOP MAX5922CEUI 28 TSSOP Pin Configuration TOP VIEW DRAIN 1 DRAIN 2 N. RCL 5 MAX5922A N.C. 6 MAX5922B MAX5922C AGND_S 7 UVLO 8 RDT ...

Page 20

Single-Port Network Power Switch For Power-Over-LAN +48V IN MAX5922A/MAX5922B RJ45 RJ45 CAT5 +48V IN +48V 47µF 100V R RCL 150Ω RDT 18.2kΩ 1% OPEN-DRAIN OUTPUTS REFERENCED TO DGND AGND 20 ______________________________________________________________________________________ Typical Application Circuits +48V POWER OVER ...

Page 21

Single-Port Network Power Switch (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information www.maxim-ic.com/packages.) Maxim cannot assume responsibility for use of any circuitry other than circuitry ...

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