NCP551, NCV551

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5

DEFINITIONS

Load Regulation

The change in output voltage for a change in output

current at a constant 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 3% below its

nominal. The junction temperature, load current, and

minimum input supply requirements affect the dropout level.

Maximum Power Dissipation

The maximum total dissipation for which the regulator

will operate within its specifications.

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.

Line Transient Response

Typical over and undershoot response when input voltage

is excited with a given slope.

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 160

°C,

the regulator turns off. This feature is provided to prevent

failures from accidental overheating.

Maximum Package Power Dissipation

The maximum power package dissipation is the power

dissipation level at which the junction temperature reaches

its maximum operating value, i.e. 125

°C. Depending on the

ambient power dissipation and thus the maximum available

output current.