MC79L00, MC79L00A Series

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4

MC79L24C

MC79L24AC

Characteristics

Symbol

Min

Typ

Max

Min

Typ

Max

Unit

–22.1

–24

–25.9

–23

–24

–25

Vdc

Input Regulation

–27 Vdc

–27.5 Vdc

–28 Vdc

–

–

–

–

–

–

–

350

300

–

–

–

–

–

–

350

–

300

mV

Load Regulation

1.0 mA

–

–

–

–

200

100

–

–

–

–

200

100

mV

Output Voltage

–27 Vdc

–28 Vdc

–

–21.4

–21.4

–

–

–

–

–26.4

–26.4

–22.8

–

–22.8

–

–

–

–25.2

–

–25.2

Vdc

Input Bias Current

–

–

–

–

6.5

6.0

–

–

–

–

6.5

6.0

mA

Input Bias Current Change

–28 Vdc

1.0 mA

–

–

–

–

1.5

0.2

–

–

–

–

1.5

0.1

mA

Output Noise Voltage

–

200

–

–

200

–

µV

Ripple Rejection

(–29

RR

30

43

–

31

47

–

dB

Dropout Voltage

–

1.7

–

–

1.7

–

Vdc

APPLICATIONS INFORMATION

Design Considerations

The MC79L00, A Series of fixed voltage regulators are

designed with Thermal Overload Protections that shuts

down the circuit when subjected to an excessive power

overload condition, Internal Short Circuit Protection that

limits the maximum current the circuit will pass.

In

many

low

current

applications,

compensation

capacitors are not required. However, it is recommended

that the regulator input be bypassed with a capacitor if the

regulator is connected to the power supply filter with long

wire length, or if the output load capacitance is large. An

input bypass capacitor should be selected to provide good

high–frequency characteristics to insure stable operation

under all load conditions. A 0.33

µF or larger tantalum,

mylar, or other capacitor having low internal impedance at

high frequencies should be chosen. The bypass capacitor

should be mounted with the shortest possible leads directly

across the regulator’s input terminals. Normally good

construction techniques should be used to minimize ground

loops and lead resistance drops since the regulator has no

external

sense lead. Bypassing the output is also

recommended.

Figure 1. Positive and Negative Regulator

Figure 2. Standard Application

0.1µF

0.33µF

MC78LXX

MC79LXX

0.1µF

0.33µF

Input

Output

0.1µF

0.33µF

MC79LXX

A common ground is required between the input and the output

voltages. The input voltage must remain typically 2.0 V above

the output voltage even during the low point on the ripple voltage.