MC33761

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4

DEFINITIONS

Load Regulation

The change in output voltage for a change in output

current at a constant chip temperature.

Dropout Voltage

The input/output differential at which the regulator output

no longer maintains regulation against further reductions in

input voltage. Measured when the output drops 100 mV

below its nominal value (which is measured at 1.0 V

differential value). The dropout level is affected by the chip

temperature, load current and minimum input supply

requirements.

Output Noise Voltage

This is the integrated value of the output noise over a

specified frequency range. Input voltage and output current

are kept constant during the measurement. Results are

expressed in

mVRMS.

Maximum Power Dissipation

The maximum total dissipation for which the regulator

will operate within its specs.

Quiescent Current

The quiescent current is the current which flows through

the ground when the LDO operates without a load on its

output: internal IC operation, bias etc. When the LDO

becomes loaded, this term is called the Ground current. It is

actually the difference between the input current (measured

through the LDO input pin) and the output current.

Line Regulation

The change in output voltage for a change in input voltage.

The measurement is made under conditions of low

dissipation or by using pulse technique such that the average

chip temperature is not significantly affected. One usually

distinguishes static line regulation or DC line regulation (a

DC step in the input voltage generates a corresponding step

in the output voltage) from ripple rejection or audio

susceptibility where the input is combined with a frequency

generator to sweep from a few hertz up to a defined

boundary while the output amplitude is monitored.

Thermal Protection

Internal thermal shutdown circuitry is provided to protect

the integrated circuit in the event that the maximum junction

temperature is exceeded. When activated at typically 125

°C,

the regulator turns off. This feature is provided to prevent

catastrophic failures from accidental overheating.

Maximum Package Power Dissipation

The maximum power package power dissipation is the

power dissipation level at which the junction temperature

reaches its maximum operating value, i.e. 125

°C.

Depending on the ambient temperature, it is possible to

calculate the maximum power dissipation and thus the

maximum available output current.