TLE4275V33_15 Datasheet, PDF (5/12 Pages) Infineon Technologies AG – Stable with ceramic output capacitor

TLE 4275 V33
Block Description and Electrical Characteristics
3
Block Description and Electrical Characteristics
3.1
Voltage Regulator
The output voltage V_Q is controlled by comparing a portion of it to an internal reference and driving a PNP pass
transistor accordingly. The control loop stability depends on the output capacitor C_Q, the load current, the chip
temperature and the poles/zeros introduced by the integrated circuit. To ensure stable operation, the output
capacitor’s capacitance and its equivalent series resistor ESR requirements given in the table “Operating Range”
have to be maintained. For details see also the typical performance graph “Output Capacitor Series Resistor
ESR_CQ vs. Output Current I_Q”. Also, the output capacitor shall be sized to buffer load transients.
An input capacitor C_I is strongly recommended to buffer line influences. Connect the capacitors close to the IC
terminals.
Protection circuitry prevent the IC as well as the application from destruction in case of catastrophic events. These
safeguards contain output current limitation, reverse polarity protection as well as thermal shutdown in case of
overtemperature.
In order to avoid excessive power dissipation that could never be handled by the pass element and the package,
the maximum output current is decreased at input voltages above V_I = 22 V.
The thermal shutdown circuit prevents the IC from immediate destruction under fault conditions (e.g. output
continuously short-circuited) by switching off the power stage. After the chip has cooled down, the regulator
restarts. This leads to an oscillatory behaviour of the output voltage until the fault is removed. However, junction
temperatures above 150 °C are outside the maximum ratings and therefore significantly reduce the IC lifetime.
The TLE 4275 V33 allows a negative supply voltage. However, several small currents are flowing into the IC
increasing its junction temperature. This has to be considered for the thermal design, respecting that the thermal
protection circuit is not operating during reverse polarity conditions For details see typical performance graphs.
Supply
I
Saturation Control
Current Limitation
C
I
Temperature
Shutdown
Blo c k Dia gra m _Vo lta ge Re gu la tor.v s d
Q
Regulated Output Voltage
Bandgap
Reference
GND
C
ESR
}C
Q
LOAD
Figure 3 Block Diagram Voltage Regulator Circuit
Datasheet
5
Rev. 1.1, 2015-01-15