LP2980 datasheet(5/18 Pages) NSC

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Electrical Characteristics (Continued)

Note 3: The maximum allowable power dissipation is a function of the maximum junction temperature, TJ(MAX), the junction-to-ambient thermal resistance, θJA, and

the ambient temperature, TA. The maximum allowable power dissipation at any ambient temperature is calculated using:

The value of

θJA for the SOT-23 package is 220˚C/W and the micro SMD package is 320˚C/W. Exceeding the maximum allowable power dissipation will cause ex-

cessive die temperature, and the regulator will go into thermal shutdown.

Note 4: If used in a dual-supply system where the regulator load is returned to a negative supply, the LP2980 output must be diode-clamped to ground.

Note 5: The output PNP structure contains a diode between the VIN and VOUT terminals that is normally reverse-biased. Reversing the polarity from VIN to VOUT

will turn on this diode (see Application Hints).

Note 6: Limits are 100% production tested at 25˚C. Limits over the operating temperature range are guaranteed through correlation using Statistical Quality Control

(SQC) methods. The limits are used to calculate National’s Average Outgoing Quality Level (AOQL).

Note 7: Dropout voltage is defined as the input to output differential at which the output voltage drops 100 mV below the value measured with a 1V differential.

Note 8: The ON/OFF inputs must be properly driven to prevent misoperation. For details, refer to Application Hints.

Note 9: See Typical Performance Characteristics curves.

Basic Application Circuit

DS012078-2

*ON/OFF input must be actively terminated. Tie to VIN if this function is not to be used.

**Minimum Output Capacitance is 1 µF to insure stability over full load current range. More capacitance provides superior dynamic performance and additional

stability margin (see Application Hints).

***Do not make connections to this pin.

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