LM317L

3TERMINAL ADJUSTABLE REGULATOR

SLCS144 − JULY 2004

4

POST OFFICE BOX 655303

APPLICATION INFORMATION

Figure 1. Adjustable Voltage Regulator

C1 = 0.1

µF

(see Note A)

VI

470

Ω

R1

R2

C2 = 1

µF

(see Note C)

VO

(see Note B)

Adjustment

Output

Input

LM317L

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:

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.

V

R2

R1

Figure 2. 0-V to 30-V Regulator Circuit

VO

(see Note A)

R2 = 3 k

Ω

1N4002

R3 =

820

Ω

−10 V

C1 = 0.1

µF

35 V

Adjustment

Output

Input

LM317L

NOTE A: Output voltage is calculated from the equation:

where: Vref equals the difference between OUTPUT

and ADJUSTMENT voltages (

≈1.25 V).

R1 = 120

Ω

V

R2

) R3

R1

* 10 V

Figure 3. Regulator Circuit

With Improved Ripple Rejection

R1 =

470

Ω

D1†

1N4002

C3 = 1

µF

C2 = 10

µF

R2 =

10 k

Ω

VI

+

+

−

−

Adjustment

Output

Input

LM317L

† D1 discharges C2 if output is shorted to ground.

NOTE A: Use of an output capacitor improves transient response, but is

optional.

VO

(see Note A)

C1 =

0.1

µF

Figure 4. Precision Current-Limiter Circuit

VI

R1

Adjustment

Output

Input

LM317L

I

1.25

R1