Preliminary

TS4268

180mA Ultra Low Dropout Voltage Regulator

with Reset & Watchdog Function

2/7

Version: Preliminary

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 1.35V, the external reset delay capacitor is discharged by

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 4.5V. 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. TS4268 is also incorporates a member of internal circuits for protection against:

• Over load

• Over temperature

• Reverse polarity

Block Diagram