TS5201_08 Datasheet, PDF (4/7 Pages) Taiwan Semiconductor Company, Ltd – 200mA Low Noise LDO Voltage Regulator with Enable

TS5201
200mA Low Noise LDO
Voltage Regulator with Enable
Application Information (Continue)
No Load Stability
The TS5201 series will remain stable and in regulation with no load, unlike many other voltage regulators. This is
especially important in CMOS RAM keep alive applications.
Adjustable Regulator Design
The adjustable regulator versions can be adjusted to a specific output voltage by using two external resistors to
programming the output voltage anywhere between 1.25 and the 8V maximum operating rating of the family.
Two resistors are used. Resistors can be quite large up to 470kΩ, because of the very high input impedance and low
bias current of the sense comparator, the resistor values are calculated by:
A capacitor from Adjust to Ground provides greatly improved noise performance.
V_OUT
V_IN
C_OUT
R1
2.2uF
R2
EN
on
off
Adjustable Version: V_OUT = 1.24 (R1+R2)/R2
(Adjustable output range up to 8V)
Dual Supply Operation
When used in dual supply systems where the regulator load is returned to a negative supply, the output voltage must
be diode clamped to ground.
Thermal Characteristics
TS5201 series is designed to provide 200mA (5V version) of continuous current in a very small package. Maximum
power dissipation can be calculated based on the output current and the voltage drop across the part. To determine
the maximum power dissipation of the package, use the junction-ambient thermal resistance of the device and the
following basic equation:
PD(MAX) = [ T_J(MAX) – T_A ] /Θ_JA
T_J(MAX) is the maximum junction temperature of the die(125ºC), and Ta is the ambient operating temperature. ΘJA is
layout dependent, the actual power dissipation of the regulator circuit can be determined using the equation:
PD = (V_IN – V_OUT) * I_OUT + V_IN * I_GND
Substituting Pd(max) for Pd and solving for the operating conditions that are critical to the application will give the
maximum operating conditions for the regulator circuit. For example, when operating the TS5201CS at room
temperature with a minimum footprint layout, the maximum input voltage for a set output current can be determined
as follows:
PD(MAX) = (125^oC – 25^oC) / 220^oC/W
PD(MAX) = 455mW
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Version: B07