SG117A/SG117 SERIES
APPLICATION INFORMATION
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 0.1µF 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
(continued)
FIGURE 20 - REMOTE SENSING
FIGURE 23 - 21V PROGRAMMING SUPPLY FOR UV PROM/EEPROM
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
1
were connected to the load, the
effective resistance between the regulator and the load would be
R
P
X
FIGURE 24 - 2816 EEPROM SUPPLY PROGRAMMER FOR READ/WRITE CONTROL
(
R
2
+ R
1
R
1
)
R
P
= Parasitic Line Resistance.
,
Connected as shown, R
P
is not multiplied by the divider ratio. R
P
is about 0.004Ω 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 25 - TEMPERATURE COMPENSATED LEAD ACID BATTERY CHARGER
2/93 Rev 1.2
10/02
Copyright
1994
7
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INFINITY
Microelectronics Inc.
MICRO-ELECTRONICS [ Micro Electronics ]
