TLF4949 Datasheet, PDF (16/23 Pages) Infineon Technologies AG – 5V Low Drop Out Linear Voltage Regulator

TLF4949
Application Information
Voltage Regulator
The voltage regulator uses a PNP transistor as a regulation element. With this structure a very low dropout voltage
at currents of up to 100mA is obtained.
The dropout operation of the standby regulator is maintained down to 3.5V input supply voltage. The output
voltage is regulated up to a transient input supply voltage of 40V. With this feature no functional interruption due
to over voltage pulses is generated. The typical curve showing the standby output voltage as a function of the input
supply voltage V_S is shown in Figure 5 “Output Voltage vs. Input Voltage” on Page 16.Typical values of the
current consumption of this device at small loads (quiescent current) are less than 200µA.
T_jJ ==2255°VC
5,00
0,00
0
5
Figure 5 Output Voltage vs. Input Voltage
10
V_IN [V]
15
40
To reduce the quiescent current peak in the undervoltage region and to improve the transient response in this
region, the dropout voltage is controlled. The quiescent current as a function of the supply input voltage is shown
for two different load conditions in Figure 6 “Quiescent Current vs. Supply Voltage” on Page 16.
3
T_J = 25 °C
2,5
2
1,5
1
0,5
0
0
5
R_LOAD = 5 kΩ
R_LOAD = 100 Ω
10
15
20
25
30
35
40
V_IN [V]
Figure 6 Quiescent Current vs. Supply Voltage
Short Circuit Protection
The maximum output current of the device is internally limited. In case of short circuit, the output current is foldback
limited as described in Figure 7 “Foldback Characteristics of VOUT” on Page 17.
Data Sheet
16
Rev. 1.0, 2012-05-07