TLE4268 Datasheet, PDF (4/13 Pages) Siemens Semiconductor Group – 5-V Low-Drop Fixed Voltage Regulator

TLE 4268
Circuit Description
The control amplifier compares a reference voltage, which is kept highly accurate by
resistance adjustment, to a voltage that is proportional to the output voltage and drives
the base of the series transistor via a buffer. Saturation control as a function of the load
current prevents any over-saturation of the power element. If The externally scaled down
output voltage at the reset threshold input drops below 1.35 V, the external reset delay
capacitor is discharged by the reset generator. If the voltage on the capacitor reaches
the lower threshold V_ST, a reset signal is generated on the reset output and not cancelled
again until the upper threshold voltage is exceeded. If the reset threshold input is
connected to GND, reset is triggered at an output voltage of 4.5 V. A connected
microcontroller is monitored by the watchdog logic. If pulses are missing, the rest output
is set to low. The pulse sequence time can be set within a wide range with the reset delay
capacitor. The IC also incorporates a member of internal circuits for protection against:
• Overload
• Overtemperature
• Reverse polarity
Input ¹⁸
Temperature
Sensor
Adjustment
Bandgap
Reference
Protection
Circuit
Control
Amplifier
4-7, 14-17
GND
Figure 3
Block Diagram
Semiconductor Group
4
12 _Output
Reset
Generator
3 Reset
Output
10
Reset
Switching
Threshold
Watchdog
9 Reset
Delay
11
Watchdog
Input
AEB01539
1998-11-01