TLE42744_14 Datasheet, PDF (13/21 Pages) Infineon Technologies AG – Very Low Current Consumption

TLE42744
6
Application Information
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
Supply
II
I
DI
< 45V
CI2
CI1
10µF 100 nF
Current
Limitation
Temperature
Shutdown
Q
IQ
Regulated
Output Voltage
Bandgap
Reference
GND
CQ
22 µF
(ESR < 3Ω)
Load
( e.g.
Micro
Controller)
GND
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(C_Q) versus Output Current I_Q” on Page 12 shows the stable operation
range of the device.
Data Sheet
13
Rev. 1.2, 2014-07-03