TLE42744

Application Information

Data Sheet

13

Rev. 1.2, 2014-07-03

6

Application Information

Note: The following information is given as a hint for the implementation of the device only and shall not be

regarded as a description or warranty of a certain functionality, condition or quality of the device.

6.1

Application Diagram

Figure 4

Application Diagram

6.2

Selection of External Components

6.2.1

Input Pin

The typical input circuitry for a linear voltage regulator is shown in the application diagram above.

A ceramic capacitor at the input, in the range of 100 nF to 470 nF, is recommended to filter out the high frequency

disturbances imposed by the line e.g. ISO pulses 3a/b. This capacitor must be placed very close to the input pin

of the linear voltage regulator on the PCB.

An aluminum electrolytic capacitor in the range of 10 µF to 470 µF is recommended as an input buffer to smooth

out high energy pulses, such as ISO pulse 2a. This capacitor should be placed close to the input pin of the linear

voltage regulator on the PCB.

An overvoltage suppressor diode can be used to further suppress any high voltage beyond the maximum rating

of the linear voltage regulator and protect the device against any damage due to over-voltage.

The external components at the input are not mandatory for the operation of the voltage regulator, but they are

recommended in case of possible external disturbances.

6.2.2

Output Pin

An output capacitor is mandatory for the stability of linear voltage regulators.

The requirement to the output capacitor is given in “Functional Range” on Page 6. The graph “Region Of

Stability: Output Capacitor’s ESR ESR(CQ) versus Output Current IQ” on Page 12 shows the stable operation

range of the device.

Supply

100nF

10µF

Regulated

Output Voltage

<45V

Load

(e.g.

Micro

Controller)

GND

Bandgap

Reference

GND

Q

I

Current

Limitation

Temperature

Shutdown

22µF

(ESR<3Ω)