TS29152_13 Datasheet, PDF (5/8 Pages) Taiwan Semiconductor Company, Ltd – 1.5A Ultra Low Dropout Voltage Regulator

TS29152
1.5A Ultra Low Dropout Voltage Regulator
Thermal Characteristics (Continue)
The next parameter which must be calculated is the maximum allowable temperature rise, T_R(max). this is
calculated by the using to formula:
T_R(max) = T_J(max) – T_A(max)
Where: T_J(max) is the maximum allowable junction temperature, which is 125^oC for commercial grade parts.
T_A(max) is the maximum ambient temperature which will be encountered in the application. Using the calculated
values for T_R(max) and P_D, the maximum allowable value for the junction to ambient thermal resistance, θ_JA, can
now be found: θ_JA = T_R(max) / P_D
Adjustable Regulator Design
The adjustable regulator versions is allow to programming the output voltage anywhere between 1.25 and the
26V maximum operating rating of the family. Two resistors are used. Resistors can be quite large up to 1MΩ,
because of the very high input impedance and low bias current of the sense comparator, the resistor values are
calculated by:
R1 = R2 * [(V_OUT / 1.24) – 1]
Where is Vout the desired output voltage. Above application circuit shows component definition. Applications with
widely varying load currents may scale the resistors to draw the minimum load current required for proper
operation.
Enable Input
TS29152 versions feature an enable (EN) input that allows ON/OFF control of the device. Special design allows
“zero” current drain when the device is disabled–only microamperes of leakage current flow. The EN input has
TTL/CMOS compatible thresholds for simple interfacing with logic, or may be directly tied to ≤30V. Enabling the
regulator requires approximately 20uA of current.
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Version: B13