LTC1921 Linear Technology, LTC1921 Datasheet - Page 8

• Manufacturer Part Number: LTC1921
• Description: Dual .48V Supply and Fuse Monitor
• Manufacturer: Linear Technology

APPLICATIO S I FOR ATIO
LTC1921
8
SUPPLY A
SUPPLY B
–48V
–48V
SUPPLY A
SUPPLY B
–48V
–48V
RETURN
U
–48V
F1
F2
U
RETURN
R1
100k
–48V
R2
100k
1
8
2
7
W
V
V
FUSE A
FUSE B
100k
A
B
LTC1921
RTN
100k
1
8
2
7
3
Figure 3a. Combined Supply Status
OUT A
OUT B
OUT F
Figure 3b. All Outputs Combined
V
V
FUSE A
FUSE B
A
B
U
1921 F03a
LTC1921
RTN
4
5
6
3
OUT A
OUT B
OUT F
MOCD207
1921 F03b
R3
47k
1/4W
= LOGIC COMMON
4
5
6
MOC207
47k
47k
48k
1/2W
–48V OUT
COMMON
LOGIC
5V
FUSE STATUS
5V
SUPPLY
STATUS
47k
–48V OUT
OK: WITHIN SPECIFICATION
0: LED/PHOTODIODE ON
1: LED/PHOTODIODE OFF
5V
STATUS
FUSE A
= V
ALL OTHER CONDITIONS
A
OK: WITHIN SPECIFICATION
OV: OVERVOLTAGE
UV: UNDERVOLTAGE
0: LED/PHOTODIODE ON
1: LED/PHOTODIODE OFF
*IF BOTH FUSES (F1 AND F2) ARE OPEN,
UV OR OV
UV OR OV
ALL STATUS OUTPUTS WILL BE HIGH
SINCE R3 WILL NOT BE POWERED
FUSE B
FUSE A
= V
= V
= V
V
OK
OK
V
V
B
A
A
A
A
A
OK
V
A
UV OR OV
UV OR OV
FUSE B
= V
= V
V
OK
V
OK
OK
V
V
B
B
B
B
B
B
STATUS
0
1
FUSE STATUS
SUPPLY STATUS
0
1
1
1*
0
1
1
1
1921i