LP3981 datasheet(5/11 Pages) NSC

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Electrical Characteristics (Continued)

Unless otherwise specified: V

EN = 1.2V, VIN =VOUT + 0.5V, CIN = 2.2 µF, CBP = 0.033 µF, IOUT = 1mA, COUT = 2.2 µF. Typi-

cal values and imits appearing in standard typeface are for T

J = 25˚C. Limits appearing in boldface type apply over the entire

junction temperature range for operation, −40˚C to +125˚C. (Notes 6, 7)

Symbol

Parameter

Conditions

Typ

Limit

Units

Min

Max

Turn-On Time

(Note 10) (Note 11)

BYPASS = 0.033 µF

240

350

µs

Note 1: Absolute Maximum Ratings are limits beyond which damage to the device may occur. Operating Ratings are conditions under which operation of the device

is guaranteed. Operating Ratings do not imply guaranteed performance limits. For guaranteed performance limits and associated test conditions, see the Electrical

Characteristics tables.

Note 2: All voltages are with respect to the potential at the GND pin.

Note 3: The figures given for Absolute Maximum Power disipation for the device are calculated using the following equations:

where TJ(MAX) is the maximum junction temperature, TA is the ambient temperature, and θ JA is the junction-to-ambient thermal resistance.

E.g. for the LLP package

θ JA=50˚C/W, TJ(MAX)=150˚C and using TA=25˚C the maximum power dissipation is found to be 2.5W. The derating factor (−1/θJA)=

−20mW/˚C, thus below 25˚C the power dissipation figure can be increased by 20W per degree, and similarity decreased by this factor for temperatures above 25˚C

Note 4: The human body model is 100pF discharged through 1.5k

Ω resistor into each pin. The machine model is a 200 pF capacitor discharged directly into each

pin.

Note 5: As for the Maximum Power dissipation, the maximum power in operation is dependant on the ambient temperature. This can be calculated in teh same way

using TJ=125˚C, giving 2W as the maximum power dissipation for the LLP package in operation. The same derating factor applies.

Note 6: All limits are guaranteed. All electrical characteristics having room-temperature limits are tested during production with TJ = 25˚C or correlated using

Statistical Quality Control (SQC) methods. All hot and cold limits are guaranteed by correlating the electrical characteristics to process and temperature variations

and applying statistical process control.

Note 7: The target output voltage, which is labeled VOUT(nom), is the desired voltage option.

Note 8: An increase in the load current results in a slight decrease in the output voltage and vice versa.

Note 9: Dropout voltage is the input-to-output voltage difference at which the output voltage is 100mV below its nominal value. This specification does not apply for

input voltages below 2.5V.

Note 10: Guaranteed by design.

Note 11: Turn-on time is time measured between the enable input just exceeding VIH and the output voltage just reaching 95% of its nominal value.

Note 12: For VOUT > 2.5C, Increase IQ(MAX) by 2.5µA for every 0.1V increase in VOUT(NOM).

i.e. IQ(MAX) = 210 + ((VOUT(NOM) - 2.5) * 25)µA

Output Capacitor, Recommended Specification

Symbol

Parameter

Conditions

Typ

Limit

Units

Min

Max

OUT

Output Capacitor

Capacitance

2.2

µF

ESR

500

Ω

20020308

FIGURE 1. Line Transient Response Input Perturbation

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