TS5201_07 Datasheet, PDF (5/7 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)
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(125^oC), and Ta is the ambient operating temperature. Θ_JA 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 TS5201CS33 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
The junction to ambient thermal resistance for the minimum footprint is 220^oC/W, the maximum power dissipation
must not be exceeded for proper operation. Using the output voltage of 3.3V and an output current of 120mA, the
maximum input voltage can be determined. From the electrical characteristics table, the maximum ground current for
120mA output current is 2.5mA.
445mW = (V_IN – 3.3V ) * 200mA + V_IN * 2.5mA
445mW = V_IN * 200mA – 3.3 * 200mA + V_IN * 2.5mA
445mW = V_IN * 200mA – 495mW + V_IN * 2.5mA
950mW = V_IN * 152.5mA
V_IN (max) = 6.23V
Therefore, a 3.3V application at 200mA of output current can accept a maximum input voltage of 6.23V in a SOP-8
package.
Noise Reduction Capacitors
On adjustable devices, a capacitor from ADJ to GND will decrease high frequency noise on the output. See following
figure:
Minimum Load
The TS5201 will remain stable and in regulation with no load unlike many other voltage regulators. This is especially
important in CMOS RAM keep-alive applications.
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Version: A07