User Manual

MAX5940A/MAX5940B
IEEE 802.3af PD Interface Controller
For Power-Over-Ethernet
12 ______________________________________________________________________________________
60V
68nF
UVLO
GND
V
EE
GATE
RCLASS
PGOOD
PGOOD
DC-DC CONVERTER
GND
-48V
WALL
ADAPTER
SUPPLY
R
CL
D1
GND
V+
VREG
OUT
1
2
3
4
5
6
7
8
C
OUT
C
GATE
R
DISC
25.5kΩ
SS_SHDN
MAX5014
MAX5940B
LOAD
R4
4kΩ
2W
D2
Typical Application Circuits (continued)
Figure 6. Adding Wall Adapter Input Supply (Wall Adapter Supply And Power-Over-Ethernet Co-Exist, the One with Higher Voltage
Provides Power To The Load)
Application Circuit 3
D2 prevents the wall adapter power from polluting the
discovery and classification signatures. The optional
R4 provides the 10mA minimum power maintenance
signature to keep the power-over-ethernet from discon-
necting.