LP2950
Figure 24. Open Circuit Detector for 4.0 to 20 mA Current Loop
+5.0 V
4.7 k
Output*
1
2
5
4
20 mA
NC
8
V
in
1
4
5
3
V
Error
out
2
NC
NC
SNS
LP2951CN
* High for
I < 3.5 mA
L
6
NC
SD
V T
O
0.1 µF
1N4001
Gnd FB
4
7
1N457
1N457
1N457
360
Figure 25. Low Battery Disconnect
31.6 k
6.0 V Lead–Acid
Battery
100 k
2N3906
NC
8
V
in
1
2
5
3
V
Main V+
Error
out
1
MC34164P–5
2
SNS
LP2951CN
Memory V+
3
1.0 µF
6
20
SD
V T
O
NC
NiCad Backup
Battery
Gnd FB
4
7
NC
Figure 26. DPAK Thermal Resistance and Maximum
Power Dissipation versus P.C.B. Copper Length
100
90
80
70
60
50
40
2.4
P
for T = 50°C
A
D(max)
Free Air
Mounted
Vertically
2.0
1.6
1.2
0.8
0.4
0
2.0 oz. Copper
L
Minimum
Size Pad
L
R
θJA
0
5.0
10
15
20
25
30
L, LENGTH OF COPPER (mm)
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