LM723
TABLE 1:
Resistor Values (K
Ω
) for standard Output Voltages
Output
Voltage
+3
+5
+6
+9
+12
+15
+28
+45
+75
+100
+250
-6**
-9
-12
-15
-28
-45
-100
-250
Fixed Output ± 5%
Applicable Figures
R1
13, 16, 17, 18, 21, 23
13, 16, 17, 18, 21, 23
13, 16, 17, 18, 21, 23
14, 16, 17, 18, 21, 23
14, 16, 17, 18, 21, 23
14, 16, 17, 18, 21, 23
14, 16, 17, 18, 21, 23
19
19
19
19
15
15
15
15
15
20
20
20
4.12
2.15
1.15
1.87
4.87
7.87
21
3.57
3.57
3.57
3.57
3.57
3.48
3.57
3.65
3.57
3.57
3.57
3.57
R2
3.01
4.99
6.04
7.15
7.15
7.15
7.15
48.7
78.7
102
255
2.43
5.36
8.45
11.5
24.3
21.2
97.6
249
R1
1.8
0.75
0.5
0.75
2
3.3
5.6
2.2
2.2
2.2
2.2
1.2
1.2
1.2
1.2
1.2
2.2
2.2
2.2
P1
0.5
0.5
0.5
1
1
1
1
10
10
10
10
0.5
0.5
0.5
0.5
0.5
10
10
10
R2
1.2
2.2
2.7
2.7
3
3
2
39
68
91
240
0.75
2
3.3
4.3
10
33
91
240
Output Adjustable ± 10% *
* Replace R1/R2 divider with the circuit of fig. 24.
** V+ must be connected to a +3V or greater supply.
TABLE 2:
Formula for Intermediate Output Voltages
Outputs from 2 to 7V
Fig. 13, 16, 17, 18, 21, 23
V
O
=(V
REF
xR
2
)/(R
1
+R
2
)
Outputs from 7 to 37V
Fig. 14, 16, 17, 18, 21, 23
V
O
=V
REF
x[(R
1
+R
2
)/R
2
]
Outputs from 4 to 250V
Fig. 19
V
O
=(V
REF
/2)x[(R
2
-R
1
)/R
1
];
R
3
=R
4
Outputs from -6 to -250V
Fig. 15, 20
V
O
=(V
REF
/2)x[(R
1
+R
2
)/R
1
];
R
3
=R
4
Current Limit
I
LIMIT
=V
SENSE
/R
SC
Foldback Current Limiting
I
KNEE
=[(V
O
xR
3
)/(R
SC
xR
4
)]x[V
SENSE
x(R
3
+R
4
)]/
(R
SC
xR
4
)
I
SHORTCKT
=(V
SENSE
/R
SC
)x[(R
3
+R
4
)/R
4
]
7/16
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