Datasheet

LTC4268-1
22
42681fc
applicaTions inForMaTion
RX
–
6
RX
+
3
TX
–
2
TX
+
RJ45
T1
1
7
8
5
4
SPARE
–
+
–
SPARE
+
ISOLATED
WALL
TRANSFORMER
TO PHY
V
PORTP
OPTION 1: AUXILIARY POWER INSERTED BEFORE LTC4268-1
OPTION 2: AUXILIARY POWER INSERTED AFTER LTC4268-1 WITH SIGNATURE DISABLED
V
PORTN
V
NEG
V
WW
V
WW
V
WW
D8
S1B
D3
SMAJ58A
TVS
C1
• 42V ≤ V
WW
≤ 57V
• NO POWER PRIORITY ISSUES
• LTC4268-1 CURRENT LIMITS FOR BOTH PoE AND V
WW
• 42V ≤ V
WW
≤ 57V
• NO POWER PRIORITY ISSUES
• NO LTC4268-1 CURRENT LIMITS FOR V
WW
• V
WW
ANY VOLTAGE BASED ON PD LOAD
• REQUIRES EXTRA DIODE
• SEE APPS REGARDING POWER PRIORITY
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
V
PORTP
LTC4268-1
LTC4268-1
BR2
~
~
+
–
BR1
~
~
+
–
BR1
~
~
+
–
V
PORTN
SHDN
BSS63
4.7k
100k
V
NEG
D10
S1B
D3
SMAJ58A
TVS
C1
D9
S1B
OPTION 3: AUXILIARY POWER APPLIED TO LTC4268-1 AND PD LOAD
RX
–
6
RX
+
3
TX
–
2
TX
+
RJ45
T1
1
7
8
5
4
SPARE
–
+
–
SPARE
+
ISOLATED
WALL
TRANSFORMER
TO PHY
V
PORTP
LTC4268-1
V
PORTN
V
NEG
D10
S1B
D3
SMAJ58A
TVS
C1
C14
0.1µF
100V
C14
0.1µF
100V
BR2
~
~
+
–
BR1
~
~
+
–
OPTION 4: AUXILIARY POWER APPLIED TO ISOLATED LOAD
BR2
~
~
+
–
V
WW
• V
WW
ANY VOLTAGE BASED ON PD LOAD
• SEE APPS REGARDING POWER PRIORITY
• BEST ISOLATION
RX
–
6
RX
+
3
TX
–
2
TX
+
RJ45
T1
1
7
8
5
4
SPARE
–
+
–
SPARE
+
ISOLATED
WALL
TRANSFORMER
TO PHY
V
PORTP
PG
GND
LTC4268-1
BR1
~
~
+
–
V
PORTN
SHDN
V
NEG
D3
SMAJ58A
TVS
C1
DRIVE LOAD
C14
0.1µF
100V
BR2
~
~
+
–
ISOLATED DC/DC CONVERTER
V
IN
V
IN
V
IN
+
+
+
+
Figure 10. Interfacing Auxiliary Power Source to the PD