LM317L
3 TERMINAL ADJUSTABLE REGULATOR
SLCS144 − JULY 2004
APPLICATION INFORMATION
LM317L
VI
Input
Output
R1
470
Ω
VO
(see Note B)
35 V
C2 = 1
µF
(see Note C)
C1 = 0.1
µF
Input
LM317L
Output
VO
(see Note A)
R1 = 120
Ω
Adjustment
C1 = 0.1
µF
(see Note A)
Adjustment
R2
−10 V
R3 =
820
Ω
1N4002
R2 = 3 kΩ
NOTES: A. Use of an input bypass capacitor is recommended if
regulator is far from the filter capacitors.
B. Output voltage is calculated from the equation:
V
O
+
V
ref
1
)
R2
R1
where: Vref equals the difference between OUTPUT and
ADJUSTMENT voltages (≈1.25 V).
C. Use of an output capacitor improves transient response,
but is optional.
NOTE A: Output voltage is calculated from the equation:
V
O
+
V
ref
1
)
R2
)
R3
*
10 V
R1
where: Vref equals the difference between OUTPUT
and ADJUSTMENT voltages (≈1.25 V).
Figure 1. Adjustable Voltage Regulator
Figure 2. 0-V to 30-V Regulator Circuit
LM317L
VI
C1 =
0.1
µF
R2 =
10 kΩ
+
−
Input
Output
R1 =
470
Ω
D1†
1N4002
+
C2 = 10
µF
−
C3 = 1
µF
VO
(see Note A)
Adjustment
LM317L
† D1 discharges C2 if output is shorted to ground.
NOTE A: Use of an output capacitor improves transient response, but is
optional.
VI
Input
Output
R1
I
limit
+
1.25
R1
Adjustment
Figure 3. Regulator Circuit
With Improved Ripple Rejection
Figure 4. Precision Current-Limiter Circuit
4
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•
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