L78M00AB View Datasheet(PDF) - STMicroelectronics
Part Name
Description
MFG CO.
'L78M00AB' PDF : 17 Pages View PDF
L78M00AB/AC SERIES
APPLICATIONS INFORMATION
DESIGN CONSIDERATIONS
The L78M00AB Series of fixed voltage regulators are designed with Thermal Overload Protection 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, and Output Transistor Safe-Area
Compensation that reduces the output short-circuit as the voltage across the pass transistor is increased.
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 lengths, 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 0.33µF 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 regulators 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.
Figure 13 : Current Regulator
IO = VRx1x + Id
Figure 14 : Adjustable Output Regulator
VO, 7.0V to 20V
VI - VO ≥ 2.0V
The addition of an operational amplifier allows adjustment to higher or intermediate values while retaining regulation characteristics. The min-
imum voltage obtainable with this arrangement is 2.0V greater than the regulator voltage.
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