KSD-I0T005-008

9

SJ1117xxx

Load Regulation

Load regulation will be limited by the resistance of the wire connecting the regulator to the load. The

specification for load regulation is measured at the output pin of the device. Negative side sensing is a

true Kelvin connection, with the bottom of the output divider returned to the negative side of the load.

Although it may not be immediately obvious, best load regulation is obtained when the top of the resistor

divider (R1) is returned directly to the output pin of the device(See Fig.10).

For example, a 5V regulator with 0.05Ω resistance(Rp) between the regulator and load will have a load

regulation due to line resistance of (Rp x IL). If R1 is connected near the load, the effective line resistance

will be Rp (1+R2/R1) or in this case, it is 4 times worse. In addition, the ground side of the resistor R2

can be returned near the ground of the load to provide remote ground sensing and improve load regulation.

Protection Diodes

Diodes between input and output are not usually needed. The internal diode between the output and input

pins of the device can withstand microsecond surge currents of 10A to 20A. Normal power supply

cycling can not generate currents of this magnitude. Only with extremely large output capacitors, such as

1000μF and larger, and with the input pin

instantaneously shorted to ground can damage

occur. A crowbar circuit at the input of the

SJ1117 in combination with a large output

capacitor could generate currents large

enough to cause damage. In this case a diode

from output to input is recommended,

as shown in Figure 11.

Fig.14 Connections for Best Load Regulation

Fig.15 Protection Diodes

SJ1117

IN

OUT

ADJ

VIN

VOUT

+

100uF

1N4002

(OPTIONAL)

R1

R2

+

10uF