TLF4949 Datasheet, PDF (15/23 Pages) Infineon Technologies AG – 5V Low Drop Out Linear Voltage Regulator

TLF4949
Application Information
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.
V_Batt
IN
Preregulator 5V
Application_diagram .vsd
PRE
OUT
RO
Reset
Bandgap
Reference
SO
SI
GND
D
Figure 4 Application Diagram
Note: This is a very simplified example of an application circuit. The function must be verified in the real application
5.1
Supply Voltage Transients
For many other voltage regulators fast supply voltage transients can often be the cause of unwanted reset output
signal perturbations. In contrast the TLF4949 shows a very high immunity of its reset output against such supply
voltage transients. Already starting from input voltages as low as 5.5 V the TLF4949 shows an immunity of the
reset output against supply transients of more than 100 V/µs even without an additional external capacitor at the
PRE pin^{1) 2)}.
5.2
Functional Description
Description
The TLF4949 is a monolithic integrated low dropout voltage regulator. Several outstanding features and auxiliary
functions are implemented to meet the requirements of supplying microprocessor systems in automotive
applications. Nevertheless, it is suitable also in other applications where the present functions are required. The
modular approach of this device allows to get easily also other features and functions when required.
1) Please note that also for the case of such input transients the absolute maximum ratings must not be violated.
2) The PRE pin of the IFX4949 offers the possibility to connect a bypass capacitor to GND to stabilize PRE output and to
optimize the transient behaviour. See also section “Preregulator ” on Page 17.
Data Sheet
15
Rev. 1.0, 2012-05-07