LP3994 datasheet(5/12 Pages) NSC

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Electrical Characteristics(Notes 2, 7) (Continued)

Unless otherwise noted, V

EN = 1.2, VIN =VOUT + 1.0V, CIN = 1 µF, IOUT = 1 mA, COUT = 1 µF. Typical values and limits ap-

pearing in normal type apply for T

J = 25˚C. Limits appearing in boldface type apply over the full temperature range for opera-

tion, −40 to +125˚C. (Notes 13, 14)

Symbol

Parameter

Conditions

Min

Typ

Max

Units

PSRR

Power Supply Rejection Ratio

f = 100Hz, I

OUT = 1mA to 50mA

f = 50kHz, I

OUT = 1mA to 50mA

f = 1MHz, I

OUT = 1mA

f = 1MHz, I

OUT = 50mA

Output noise Voltage (Note 9)

BW = 100Hz to 100kHz,

IN = 4.2V, IOUT = 1mA

µV

RMS

SHUTDOWN

Thermal Shutdown Temperature

160

˚C

Thermal Shutdown Hysteresis

Enable Control Characteristics

Maximum Input Current at

EN Input

EN = 0.0V and VIN = 5.5V

0.015

µA

Low Input Threshold

IN = 2.5V to 5.5V

0.4

High Input Threshold

IN = 2.5V to 5.5V

1.2

Timing Characteristics

ON1

Turn On Time (Note 9)

10 to 90% of V

OUT(NOM) (Note 10)

µS

ON2

To 95% Level (Note 11)

100

Transient

Response

Line Transient Response |

δV

OUT|

Figure 1 (Note 9)

Load Transient Response

δV

OUT|

Figure 2 (Note 9)

Note 1: Absolute Maximum Ratings are limits beyond which damage can 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: Internal thermal shutdown circuitry protects the device from permanent damage

Note 4: The human body is 100pF discharge through 1.5kW resistor into each pin. The machine model is a 200 pF capacitor discharged directly into each pin.

Note 5: In applications where high power dissipation and/or poor thermal resistance is present, the maximum ambient temperature may have to be derated.

Maximum ambient temperature (TA(max)) is dependant on the maximum operating junction temperature (TJ(max-op)), the maximum power dissipation (PD(max)), and

the junction to ambient thermal resistance in the application (

θJA). This relationship is given by :-

A(max) =TJ(max-op) −(PD(max) x

JA)

See Applications section.

Note 6: Junction to ambient thermal resistance is highly application and board layout dependent. In applications where high maximum power dissipation exists, the

thermal dissipation issues should be addressed in the board layout design.

Note 7: Min and Max limits are guaranteed by design, test, or statistical analysis. Typical numbers are not guaranteed, but do represent the most likely norm.

Note 8: The device maintains the regulated output voltage without the load.

Note 9: This electrical specification is guaranteed by design.

Note 10: Time for VOUT to rise from 10 to 90% of VOUT(nom).

Note 11: Time from VEN = 1.2V to VOUT = 95%(VOUT(nom)).

Note 12: Short circuit current is measured on the input supply line at the point when the short circuit condition reduces the output voltage to 95% of its nominal value.

Note 13: CIN, and COUT: Low ESR surface mont devices used in setting electrical characteristics.

Note 14: All limits are guaranteed. All electrical characteristics having room-temperature limits are tested during production at TJ = 25˚C or correlated using

Statistical Quality Control methods. Operation over the temperature specification is guaranteed by correlating the electrical characteristics to process and

temperature variations and applying statistical process control.

Output Capacitor, Recommended Specifications

Symbol

Parameter

Conditions

Min

Typ

Max

Units

Output Capacitor

Capacitance(Note 15)

0.7

1.0

µF

ESR

500

Ω

Note 15: The capacitor tolerance should be ±30% or better over the full temperature range. The full range of operating conditions for the capacitor in the application

should be considered during device selection to ensure this minimum capacitance specification is met. X7R capacitor types are recommended to meet the full device

temperature range, however X5R, Y5V, and Z5U types may be used with careful consideration of the application and its operating conditions. (See Capacitor

Sections in Application Hints.)

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