LP2957AIS National Semiconductor, LP2957AIS Datasheet - Page 3

• Manufacturer Part Number: LP2957AIS
• Description: 5V Low-Dropout Regulator for P Applications
• Manufacturer: National Semiconductor

e
SHUTDOWN INPUT
V
HYST
I
DROPOUT DETECTION COMPARATOR
I
V
V
(Max)
V
(Min)
HYST
B
OH
Limits in standard typeface are for T
less otherwise specified: V
n
SD
OL
THR
THR
Electrical Characteristics
Note 1: Absolute maximum ratings indicate limits beyond which damage to the component may occur. Electrical specifications do not apply when operating the de-
vice outside of its rated operating conditions.
Note 2: The maximum allowable power dissipation is a function of the maximum junction temperature, T
and the ambient temperature, T
Exceeding the maximum allowable power dissipation will result in excessive die temperature, and the regulator will go into thermal shutdown. The junction-to-ambient
thermal resistance of the TO-220 (without heatsink) is 60˚C/W and 73˚C/W for the TO-263. If the TO-263 package is used, the thermal resistance can be reduced
by increasing the P.C. board copper area thermally connected to the package: Using 0.5 Square inches of copper area,
area,
used, the effective junction-to-ambient thermal resistance is the sum of the junction-to-case resistance (3˚C/W), the specified thermal resistance of the heatsink se-
lected, and the thermal resistance of the interface between the heatsink and the LP2957 (see Application Hints).
Note 3: Output voltage temperature coefficient is defined as the worst case voltage change divided by the total temperature range.
Note 4: Regulation is measured at constant junction temperature using low duty cycle pulse testing. Parts are tested separately for load regulation in the load ranges
0.1 mA–1 mA and 1 mA–250 mA. Changes in output voltage due to heating effects are covered by the thermal regulation specification.
Note 5: Dropout voltage is defined as the input to output voltage differential at which the output voltage drops 100 mV below the value measured with a 1V input
to output differential.
Note 6: Ground pin current is the regulator quiescent current. The total current drawn from the source is the sum of the load current plus the ground pin current.
Note 7: Thermal regulation is defined as the change in output voltage at a time T after a change in power dissipation is applied, excluding load or line regulation ef-
fects. Specifications are for a 200 mA load pulse at V
Note 8: Voltages are referenced to the nominal regulated output voltage.
Note 9: When used in dual-supply systems where the regulator load is returned to a negative supply, the output voltage must be diode-clamped to ground.
Symbol
(ON)
JA
is 37˚C/W; and with 1.6 or more square inches of copper area,
Output Noise Voltage
(10 Hz to 100 kHz)
I
Output Turn-On
Threshold Voltage
Hysteresis
Input Bias
Current
Output “HIGH”
Leakage
Output “LOW”
Voltage
Upper Threshold
Voltage
Lower Threshold
Voltage
Hysteresis
L
= 100 mA
Parameter
A
. The maximum allowable power dissipation at any ambient temperature is calculated using:
IN
= 6V, I
L
J
= 25˚C, and limits in boldface type apply over the full operating temperature range. Un-
= 1 mA, C
C
C
V
V
V
I
(Note 8)
(Note 8)
(Note 8)
IN
O
IN(SD)
OH
IN
L
L
(Continued)
(COMP) = 400 µA
= 20V (3W pulse) for T = 10 ms.
= 2.2 µF
= 33 µF
= 4V
= 30V
Conditions
L
= 0V to 5V
= 2.2 µF, V
JA
is 32˚C/W. The junction-to-case thermal resistance is 3˚C/W. If an external heatsink is
SD
3
= 3V.
Typical
−240
−350
0.01
500
320
150
10
60
6
1.155
1.140
−320
−380
−450
−640
Min
−30
−50
J
LP2957AI
(MAX), the junction-to-ambient thermal resistance,
1.305
1.320
−150
−100
−230
−160
Max
250
400
30
50
1
2
JA
is 50˚C/W, with 1 square inch of copper
1.155
1.140
−320
−380
−450
−640
Min
−30
−50
LP2957I
1.305
1.320
−150
−100
−230
−160
Max
250
400
30
50
1
2
www.national.com
Units
RMS
mV
mV
mV
mV
mV
µV
nA
µA
V
JA
,