KSD-I0T005-008

8

SJ1117xxx

An Input capacitor is recommended. A 10μF tantalum capacitor on the input is a suitable bypassing for all

applications.

The adjust terminal can be bypassed to ground with a bypass capacitor to improve ripple rejection

This bypass capacitor prevents ripple from being amplified as the output voltage is increased. At

amplified

The R1 is the resistor between the output and the adjust pin.

Output Voltage

The SJ1117 develops a 1.25V reference voltage between the output and the adjust terminal (See Fig.9).

By placing a resistor between these two terminals, a constant current is caused to flow through R1 and

down through R2 to set the overall output voltage. Normally this current is chosen to be the specified

it represents a small error and can usually be ignored. For fixed voltage devices R1 and R2 are included in

the device.

SJ1117

IN

OUT

ADJ

VIN

VOUT

+

+

R1

R2

1

)

2

(

1

R

C

f

ADJ

RIPPLE

〈

×

×

π

Fig.13 Basic Adjustable Regulator

(

)

2

1

2

1

R

I

R

R

V

V

ADJ

REF

OUT

×

+

+

=