Rainbow Electronics MAX5940B - Manual (Page 13)

MAX5940A/MAX5940B
IEEE 802.3af PD Interface Controller
For Power-Over-Ethernet
______________________________________________________________________________________ 13
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
25.5k Ω
SS_SHDN
MAX5014
MAX5940B LOAD
Typical Application Circuits (continued)
Application Circuit 4
If the wall adapter supply comes up first, it provides
power to the load and pollute the discovery and classi-
fication signatures. If the power-over-ethernet comes
up first, it powers the load until taken over by a wall
adapter with higher output voltage.
Figure 7. Adding Wall Adapter Input Supply (the One with Higher Voltage Provides Power to the Load)