TLE7469 Datasheet, PDF (12/21 Pages) Infineon Technologies AG – Dual Low Drop Voltage Regulator

Application Information
TLE 7469
V_Bat
47
µF
e. g.
Ignition
Key
R_Vi *
100 nF
100 k
TLE 7469
I2
Q2
DT
INH
WDI
RO
SI
SO
100 nF
I1
Q1
GND
= Optional
1 µF
47
µF
XC 164
10 k
1 µF
47
µF
AEA03529_2.VSD
Figure 3 Application Diagram with Typical External Components
A typical application of the TLE 7469 is shown in Figure 3. To prevent the regulation
loop from oscillating a ceramic capacitor of C_Q1/2 ≥ 1 µF is required at each of the outputs
Q1 and Q2. In contrast to most low drop voltage regulators the TLE 7469 only needs
moderate capacitance at the outputs and tolerates ceramic capacitors to keep the
stability. This offers more design flexibility to the circuit designer enabling also to operate
the device without tantalum capacitors.
Additional a capacitor C_B of 10 … 47 µF should be used for each output Q1 and Q2 to
suppress influences from load surges to the voltage levels. This one can either be an
aluminum electrolytic capacitor or a tantalum capacitor following the application
requirements.
General recommendation at Tj<90°C is to keep the drop over the equivalent serial
resistor (ESR) together with the discharge of the blocking capacitor below 300mV.
Since the regulator output current roughly rises linearly with time the discharge of the
capacitor can be calculated as:
dVC_B = dI_Q*dt/C_B
Final Data Sheet
12
Rev. 1.3, 2004-10-28