Datasheet

LTC4257
14
4257fb
APPLICATIO S I FOR ATIO
WUUU
Figure 9. Auxiliary Power Source for PD
RX
–
6
RX
+
3
TX
–
2
TX
+
RJ45
T1
1
7
8
5
4
SPARE
–
+
–
SPARE
+
ISOLATED
WALL
TRANSFORMER
TO PHY
GND
8
45
OPTION 1: AUXILIARY POWER INSERTED BEFORE LTC4257
OPTION 2: AUXILIARY POWER INSERTED AFTER LTC4257
V
IN
V
OUT
44V TO 57V
D8
S1B
D3
SMAJ58A
TVS
C1
PD
LOAD
C14
0.1µF
100V
RX
–
6
RX
+
3
TX
–
2
TX
+
RJ45
T1
1
7
8
5
4
SPARE
–
+
–
SPARE
+
ISOLATED
WALL
TRANSFORMER
TO PHY
GND
LTC4257
LTC4257
BR2
DF01SA
~
~
+
–
BR1
DF01SA
~
~
+
–
BR1
DF01SA
~
~
+
–
8
45
V
IN
V
OUT
42571 F09
D10
S1B
D3
SMAJ58A
TVS
C1
MINIMUM
LOAD
PD
LOAD
D9
S1B
OPTION 3: AUXILIARY POWER APPLIED TO LTC4257 AND PD LOAD
RX
–
6
RX
+
3
TX
–
2
TX
+
RJ45
T1
1
7
8
5
4
SPARE
–
+
–
SPARE
+
ISOLATED
WALL
TRANSFORMER
TO PHY
44V TO 57V
GND
LTC4257
8
45
V
IN
V
OUT
D10
S1B
D3
SMAJ58A
TVS
C1
PD
LOAD
C14
0.1µF
100V
C14
0.1µF
100V
BR2
DF01SA
~
~
+
–
BR1
DF01SA
~
~
+
–
BR2
DF01SA
~
~
+
–