LP3997 datasheet(5/11 Pages) NSC

5 / 11 page

Electrical Characteristics (Continued)

Unless otherwise noted, V

SD =950mV, VIN =VOUT + 1.0V, CIN = 2.2 µF, IOUT = 1 mA, COUT =2.2 µF and CNOISE = 0.1 µF.

Typical values and limits appearing in normal type apply for T

J = 27˚C. Limits appearing in boldface type apply over the full

temperature range for operation, −40 to +125˚C. (Note 11)

Symbol

Parameter

Conditions

Typ

Limit

Units

Min

Max

HYST

Hysteresis

IN Rising or Falling

OUT

ErrorOutput low Voltage

SINK = 2mA

0.4

OFF

Error Output High Leakage

ERROR = V

OUT(NOM)

µA

DELAY

Delay Pin Current Source

OUT > 95% VOUT(NOM)

2.2

µA

Timing Characteristics

Turn On Time (Note 8)

To 95% Level

w/o C

NOISE

150

250

µs

NOISE = 0.1µF

Transient

Response

Line Transient Response |

δV

OUT|Trise =Tfall = 30µs (Note 8)

δV

IN = 600mV

TBA

(pk - pk)

Load Transient Response

δV

OUT|

rise =Tfall = 1µs (Note 8)

OUT = 1mA to 150mA

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 model is 100pF discharged through a 1.5k

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

pin.

Note 5: The maximum ambient temperature (TA(max)) is dependant on the maximum operating junction temperature (TJ(max-op) = 125˚C), the maximum power

dissipation of the device in te application (PD(max)), and the junction to ambient thermal resistance of the part/package in the application (θJA), as given by the

following equation: TA(max) =TJ(max-op) -(θJA xPD(max)).

Note 6: Junction to ambient thermal resistance is dependant on the application and board layout. In applications where high maximum power dissipation is possible,

special care must be paid to thermal dissipation issues in board design.

Note 7: The device maintains the regulated output voltage without the load.

Note 8: This electrical specification is guaranteed by design.

Note 9: Short circuit current is measured on the input supply line at the point when the short circuit condition reduces the output voltage to 5% of its nominal value.

Note 10: Enable Pin has 6M

Ω typical, resistor connected to GND.

Note 11: 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

Typ

Limit

Units

Min

Max

Output Capacitor

Capacitance(Note 12)

1.0

0.7

µF

ESR

500

Ω

Note 12: The capacitor tolerance should be 30% or better over temperature. The full operating conditions for the application should be considered when selecting

a suitable capacitor to ensure that the minimum value of capacitance is always met. Recommended capacitor type is X7R. However, dependent on application, X5R,

Y5V, and Z5U can also be used. (See capacitor characteristics section in Application Hints)

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