LM323, A

5

MOTOROLA ANALOG IC DEVICE DATA

Figure 9. Dropout Voltage

Figure 10. Short Circuit Current

0

102030

40

0.8

0.6

0.4

0.2

0

–0.2

–0.4

–0.6

1.0

0.5

0

t, TIME (

µs)

Iout = 150 mA

CO = 0

TJ = 25°C

1.0

0

102030

40

t, TIME (

µs)

Vin = 10 V

CO = 0

TJ = 25°C

0.3

0.2

0.1

0

–0.1

–0.2

–0.3

1.5

0.5

0

Figure 11. Line Transient Response

Figure 12. Load Transient Response

2.5

2.0

1.5

1.0

0.5

–90

–50

–10

30

70

110

150

190

TJ, JUNCTION TEMPERATURE (°C)

Iout = 3.0 A

Iout = 1.0 A

Iout = 0.5 A

∆Vout = 50 mV

8.0

6.0

4.0

2.0

0

5.0

10

15

20

25

Vin, INPUT VOLTAGE (Vdc)

TJ = 0°C

TJ = 25°C

TJ = 125°C

APPLICATIONS INFORMATION

Design Considerations

The LM323,A 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 current 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 0.33

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.