SG117A/SG117 SERIES

2/93 Rev 1.1 2/94

Copyright

© 1994

11861 Western Avenue

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∞ Garden Grove, CA 92841

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(714) 898-8121

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BYPASS CAPACITORS

Input bypassing using a 1µF tantalum or 25µF electrolytic is

recommended when the input filter capacitors are more than 5

inches from the device.

A 0.1

µF bypass capacitor on the

ADJUST pin is required if the load current varies by more than 1A/

µsec. Improved ripple rejection (80dB) can be accomplished by

adding a 10µF capacitor from the adjust pin to ground. For

improved AC transient response and to prevent the possibility of

oscillation due to unknown reactive load, a 1µF capacitor is also

recommended at the output. Because of their low impedance at

high frequencies, the best type of capacitor to use is solid

tantalum.

FIGURE 22 - 5V REGULATOR WITH SHUT DOWN

FIGURE 23 - 21V PROGRAMMING SUPPLY FOR UV PROM/EEPROM

FIGURE 24 - 2816 EEPROM SUPPLY PROGRAMMER FOR READ/WRITE CONTROL

FIGURE 25 - TEMPERATURE COMPENSATED LEAD ACID BATTERY CHARGER

FIGURE 21 - IMPROVING RIPPLE REJECTION

LOAD REGULATION

Because the SG117A is a three-terminal device, it is not possible

to provide true remote load sensing. Load regulation will be

limited by the resistance of the wire connecting the regulator to

the load. For the data sheet specification, regulation is measured

at the bottom of the package. 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 immedi-

ately obvious, best load regulation is obtained when the top of the

divider is connected directly to the case, not to the load. This is

illustrated in Figure 18. If R

effective resistance between the regulator and the load would be

Connected as shown, R

is about 0.004

Ω per foot using 16 gauge wire. This translates to

4mV/ft. at 1A load current, so it is important to keep the positive

lead between regulator and load as short as possible.

FIGURE 20 - REMOTE SENSING

(

)

R

,R

R

R

1