TS5213 datasheet(4/8 Pages) TSC

4 / 8 page

TS5213

80mA Low Noise LDO Voltage Regulator

with Enable Function

4/8

Version: B07

Application Information (Continue)

Thermal Characteristics

TS5213 series is designed to provide 80mA 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) = [ TJ(MAX) – TA ] /ΘJA

TJ(MAX) is the maximum junction temperature of the die(125

oC), 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 = (VIN – VOUT) * IOUT + VIN * IGND

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 TS5213CX550 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 – 25oC) / 220oC/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 5.0V and an output current of 80mA, the

maximum input voltage can be determined. Form the electrical characteristics table, the maximum ground current for

80mA output current is 1mA.

445mW = (VIN – 5.0V ) * 80mA + VIN * 1.8mA

445mW = VIN * 80mA – 5.0 * 80mA + VIN * 1.8mA

445mW = VIN * 80mA – 400mW + VIN * 1.8mA

845mW = VIN * 81.8mA

VIN (max) = 10.33V

Therefore, a 5.0V application at 80mA of output current can accept a maximum input voltage of 10.33V in a SOT-25

package.

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