MAX5940A(2003) Ver la hoja de datos (PDF) - Maxim Integrated

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componentes Descripción

Fabricante

MAX5940A
(Rev.:2003)

IEEE 802.3af PD Interface Controller For Power-Over-Ethernet

Maxim Integrated 

IEEE 802.3af PD Interface Controller

For Power-Over-Ethernet

Typical Application Circuits (continued)

Application Circuit 2

Diode D1 prevents the power-over-ethernet to back

drive the wall adapter. Whenever the wall adapter

power is available, the GATE is pulled low to pinch off

the power-over-ethernet. R3 provides the GATE current

flow path. The wall adapter power pollutes the discov-

ery signature, preventing PSE from detecting this PD.

GND

60V

RDISC

25.5kΩ

68nF

RCL

-48V

WALL

ADAPTER

SUPPLY

D1

1 UVLO

8

GND

2 RCLASS

7

PGOOD

3 GATE

MAX5940B

PGOOD

6

4 VEE

OUT 5

R3

10kΩ

CGATE

DC-DC CONVERTER

V+

COUT

MAX5014

GND

SS_SHDN

VREG

LOAD

Figure 5. Adding Wall Adapter Input Supply (Wall Adapter Supply Takes Precedence Over Power-Over-Ethernet)

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