TS4270 Taiwan Semiconductor Company, Ltd. (TSC), TS4270 Datasheet - Page 3

• Manufacturer Part Number: TS4270
• Description: 5v Ultra Low Dropout Fixed Voltage Regulator
• Manufacturer: Taiwan Semiconductor Company, Ltd. (TSC)

Block Diagram
Application Description
The IC regulates an input voltage in the range of 5.5V < V
output current of more than 550mA. Above 26V the save-operating-area protection allows operation up to 36V with a
regulated output current of more than 300mA. Over voltage protection limits operation at 42V. The over voltage
protection hysteresis restores operation if the input voltage has dropped below 36V. A reset signal is generated for an
output voltage of V
Design Notes for External Components
An input capacitor C
inductance and input capacitance can be damped by a resistor of approx.1Ω W i n series with C
is necessary for the stability of the regulating circuit. Stability is guaranteed at values of C
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 a series transistor via a buffer. Saturation
control as a function of the load current prevents any over-saturation of the power element. If the output voltage
decreases below 4.5V, an external capacitor C
voltage on this capacitor drops below V
low. If the output voltage rises above 4.5V, C
voltage on the capacitor reaches V
can be set within a wide range depending of the capacitance of C
The IC also incorporate a number of internal circuits for protection against:
•
•
•
•
Overload
Over Voltage
Over temperature
Reverse Polarity
O
<4.5V. The delay for power-on reset can be set externally with a capacitor.
I
is necessary for compensation of line influences. The resonant circuit consisting of lead
DU
and the reset output will be set high again. The value of the power-on-reset time
DLR
, a reset signal is generated on pin 2 (Reset Output), i.e. reset output is set
Preliminary
5V Ultra Low Dropout Fixed Voltage Regulator
D
D
will be charged with constant current. After the power-on-reset time the
on pin 4 (Reset Delay) will be discharged by the reset generator. If the
3/9
I
 < 36V to V
D
.
Onom
= 5.0V Up to 26V it produces a regulated
O
≥ 22uF and ESR of < 3Ω.
I
. An output capacitor C
TS4270
Version: A07
O