LD1117/A

LINEAR INTEGRATED CIRCUIT

UNISONICTECHNOLOGIESCO.,LTD

11 of 12

www.unisonic.com.tw

QW-R102-006,Q

APPLICATION NOTE of LD1117/A ADJUSTABLE

(120

R1 is normally fixed to 120

Ω.

From figure 4 we obtain:

For better load regulation, realize a good Kelvin connection of R1 and R2 is important. Particularly R1

connection must be realized very close to OUT and ADJ pin, while R2 ground connection must be placed as

near as possible to the negative Load pin. Ripple rejection can be improved by introducing a 10

μF electrolytic

capacitor placed in parallel to the R2 resistor (See Fig. 5)

IN

OUT

ADJ

UTC LD1117/A

+

+

10μF

10μF

R1

120Ω

R2

FIG.4 Adjustable Output Voltage Application Circuit

FIG.5 Adjustable Output Voltage Application with improved Ripple Rejection.