Typical Applications (Continued)
3
1
KA78XXE
Output
Input
2
CO
CI
0.1μF
0.33μF
Figure 9. Fixed Output Regulator
3
1
Output
KA78XXE
Input
CI
2
CO
Vxx
0.1 μF
0.33 μF
R1
IQ
IO
RL
Vxx
R1
IO =
+
IQ
Figure 10. Constant Current Regulator
Notes:
33. To specify an output voltage, substitute voltage value for “XX”. A common ground is required between the input and
the output voltage. The input voltage must remain typically 2.0 V above the output voltage even during the low
point on the input ripple voltage.
34. CI is required if regulator is located an appreciable distance from power supply filter.
35. CO improves stability and transient response.
Output
3
1
KA78XXE
Input
Vxx
2
CO
R1
R2
CI
0.1 μF
0.33 μF
IQ
IRI ≥ 5IQ
VO = VXX(1+R2/R1) + IQR2
Figure 11. Circuit for Increasing Output Voltage
© 2006 Fairchild Semiconductor Corporation
KA78XXE / KA78XXAE Rev. 1.9
www.fairchildsemi.com
21
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