LP2989IM-2.5 National Semiconductor, LP2989IM-2.5 Datasheet - Page 11

• Manufacturer Part Number: LP2989IM-2.5
• Description: IC,VOLT REGULATOR,FIXED,+2.5V,BIPOLAR,SOP,8PIN,PLASTIC
• Manufacturer: National Semiconductor

Specifications of LP2989IM-2.5

• Rohs Compliant: NO

Application Hints
est of the three types listed, their capacitance is very stable
with temperature, and DC leakage currrent is extremely low.
One disadvantage is that film capacitors are larger in physi-
cal size than ceramic or tantalum which makes film a poor
choice for either input or output capacitors.
However, their low leakage makes them a good choice for
the noise bypass capacitor. Since the required amount of ca-
pacitance is only .01 µF, small surface-mount film capacitors
are avalable in this size.
SHUTDOWN INPUT OPERATION
The LP2989 is shut off by driving the Shutdown input low,
and turned on by pulling it high. If this feature is not to be
used, the Shutdown input should be tied to V
regulator output on at all times.
To assure proper operation, the signal source used to drive
the Shutdown input must be able to swing above and below
the specified turn-on/turn-off voltage thresholds listed in the
Electrical Characteristics section under V
To prevent mis-operation, the turn-on (and turn-off) voltage
signals applied to the Shutdown input must have a slew rate
which is
40 mV/µs.
(Continued)
ON/OFF
IN
.
to keep the
11
CAUTION: the regulator output voltage can not be guaran-
teed if a slow-moving AC (or DC) signal is applied that is in
the range between the specified turn-on and turn-off volt-
ages listed under the electrical specification V
Electrical Characteristics).
REVERSE INPUT-OUTPUT VOLTAGE
The PNP power transistor used as the pass element in the
LP2989 has an inherent diode connected between the regu-
lator output and input.
During normal operation (where the input voltage is higher
than the output) this diode is reverse-biased.
However, if the output is pulled above the input, this diode
will turn ON and current will flow into the regulator output.
In such cases, a parasitic SCR can latch which will allow a
high current to flow into V
can damage the part.
In any application where the output may be pulled above the
input, an external Schottky diode must be connected from
V
verse voltage across the LP2989 to 0.3V (see Absolute
Maximum Ratings).
IN
to V
OUT
(cathode on V
IN
IN
, anode on V
(and out the ground pin), which
OUT
), to limit the re-
ON/OFF
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(see