Datasheet
IFX25401
Application Information
Data Sheet 13 Rev. 1.02, 2012-08-24
5 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.
Figure 3 Application Diagram
A typical application circuit of the IFX25401 is shown in Figure 3. It shows a generic configuration of the voltage
regulator with a recommended minimum number of components. The small input capacitor is not required but
recommended for high frequency noise filtering. For a normal operation the fixed output voltage regulator only
requires an output capacitor for stability. The adjustable output regulator requires an additional resistor network to
configure the output voltage. Depending on the application conditons, additional components such as an input
buffer capacitor or a reverse polarity protection diode can be considered as well.
Input Filter Capacitor
A small ceramic capacitor (e.g. 100nF in Figure 3) at the device’s input helps filtering high frequency noise. To
reach the best filter effect, this capacitor should be placed as close as possible to the device’s input pin. The input
filter capacitor does not have an influence on the stability of the device’s regulation loop.
Output Capacitor
C
Q
The output capacitor is the only external component that is required because it is part of the regulation loop. To
maintain stability of this regulation loop, the IFX25401 requires an output capacitor respecting the values given in
“Functional Range” on Page 6.
Adjusting the Output Voltage of Variable Output Regulators IFX25401TBV, IFX25401TEV
The output voltage of the IFX25401TBV and the IFX25401TEV can be adjusted between 2.5 V and 20 V by an
external resistor divider connected to the voltage adjust pin VA.
The VA pin is connected to the internal error amplifier comparing the voltage at this pin with the internal reference
voltage (i.e. 2.5 V).
C
Q
R
1
2
R
Output
Input
IFX25401
Optional for adjustable Voltage Regulator
I
C
Voltage
Adjust
e.g. KL 15
)
*
)
*
)
*
*
)
I
1Q5
GND
VA
4
3
2
EN