LP2981IM5-5.0 National Semiconductor, LP2981IM5-5.0 Datasheet - Page 12
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LP2981IM5-5.0
Manufacturer Part Number
LP2981IM5-5.0
Description
Linear Voltage Regulator IC
Manufacturer
National Semiconductor
Datasheets
1.LP2981IM5-5.0.pdf
(16 pages)
2.LP2981IM5-5.0.pdf
(16 pages)
3.LP2981IM5-5.0.pdf
(16 pages)
Specifications of LP2981IM5-5.0
No. Of Pins
5
Output Current
0.1A
Mounting Type
Surface Mount
Voltage Regulator Type
LDO Linear
Peak Reflow Compatible (260 C)
No
Output Voltage
5V
Current Rating
0.1A
Output Voltage Max
5V
Lead Free Status / RoHS Status
Contains lead / RoHS non-compliant
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Company:
Part Number:
LP2981IM5-5.0
Manufacturer:
NS
Quantity:
5 321
Company:
Part Number:
LP2981IM5-5.0
Manufacturer:
NS
Quantity:
11
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Application Hints
REVERSE CURRENT PATH
The power transistor used in the LP2981 has an inherent di-
ode connected between the regulator input and output (see
below).
FIGURE 3. 3V/3.3 µF ESR Curves
FIGURE 2. 5V/10 µF ESR Curves
FIGURE 4. 3V/10 µF ESR Curves
(Continued)
DS012506-39
DS012506-40
DS012506-42
12
If the output is forced above the input by more than a V
this diode will become forward biased and current will flow
from the V
This current must be limited to
to the part.
The internal diode can also be turned on by abruptly step-
ping the input voltage to a value below the output voltage.
To prevent regulator mis-operation, a Schottky diode should
be used in any application where input/output voltage condi-
tions can cause the internal diode to be turned on (see be-
low).
As shown, the Schottky diode is connected in parallel with
the internal parasitic diode and prevents it from being turned
on by limiting the voltage drop across it to about 0.3V.
ON/OFF INPUT OPERATION
The LP2981 is shut off by pulling the ON/OFF input low, and
turned on by driving the input high. If this feature is not to be
used, the ON/OFF input should be tied to V
regulator on at all times (the ON/OFF input must not be left
floating).
To ensure proper operation, the signal source used to drive
the ON/OFF input must be able to swing above and below
the specified turn-on/turn-off voltage thresholds which guar-
antee an ON or OFF state (see Electrical Characteristics).
The ON/OFF signal may come from either a totem-pole out-
put, or an open-collector output with pull-up resistor to the
LP2981 input voltage or another logic supply. The high-level
voltage may exceed the LP2981 input voltage, but must re-
main within the Absolute Maximum Ratings for the ON/OFF
pin.
It is also important that the turn-on/turn-off voltage signals
applied to the ON/OFF input have a slew rate which is
greater than 40 mV/µs.
Important: the regulator shutdown function will operate incor-
rectly if a slow-moving signal is applied to the ON/OFF input.
Micro SMD Mounting
The micro SMD package requires specific mounting tech-
niques which are detailed in National Semiconductor Appli-
cation Note # 1112. Referring to the section Surface Mount
Technology (SMT) Assembly Considerations , it should be
noted that the pad style which must be used with the 5-pin
package is the NSMD (non-solder mask defined) type.
OUT
terminal to V
IN
.
<
100 mA to prevent damage
DS012506-41
IN
DS012506-43
to keep the
BE
,