LP2980AIM5-1.8/NOPB National Semiconductor, LP2980AIM5-1.8/NOPB Datasheet - Page 12
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LP2980AIM5-1.8/NOPB
Manufacturer Part Number
LP2980AIM5-1.8/NOPB
Description
IC REG LDO MICROPOWER SOT23-5
Manufacturer
National Semiconductor
Datasheet
1.LP2980AIM5X-4.7NOPB.pdf
(16 pages)
Specifications of LP2980AIM5-1.8/NOPB
Regulator Topology
Positive Fixed
Voltage - Output
1.8V
Voltage - Input
2.1 ~ 16 V
Voltage - Dropout (typical)
0.12V @ 50mA
Number Of Regulators
1
Current - Output
50mA
Current - Limit (min)
100mA
Operating Temperature
-40°C ~ 125°C
Mounting Type
Surface Mount
Package / Case
SOT-23-5, SC-74A, SOT-25
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Other names
LP2980AIM5-1.8
LP2980AIM5-1.8TR
LP2980AIM5-1.8TR
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Part Number:
LP2980AIM5-1.8/NOPB
Manufacturer:
TI/德州仪器
Quantity:
20 000
www.national.com
REVERSE CURRENT PATH
The internal PNP power transistor used as the pass element
in the LP2980 has an inherent diode connected between the
regulator output and input. During normal operation (where
the input voltage is higher than the output) this diode is re-
verse biased (See Figure 4).
However, if the input voltage is more than a V
output voltage, 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 the V
the ground pin, which can damage the part.
The internal diode can also be turned on if the input voltage
is abruptly stepped down to a voltage which is a V
the output voltage.
FIGURE 4. LP2980 Reverse Current Path
FIGURE 3. 10 μF ESR Range
1207850
IN
BE
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pin and out
below the
BE
below
12
In any application where the output voltage may be higher
than the input voltage, an external Schottky diode must be
connected from V
V
LP2980 to 0.3V (See Absolute Maximum Ratings).
ON/OFF INPUT OPERATION
The LP2980 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
ulator 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 guarantee
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
LP2980 input voltage or another logic supply. The high-level
voltage may exceed the LP2980 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 not oper-
ate correctly if a slow-moving signal is used to drive the ON/
OFF input.
FIGURE 5. Adding External Schottky Diode Protection
OUT
. See Figure 5), to limit the reverse voltage across the
IN
to V
OUT
(cathode on V
IN
to keep the reg-
IN
, anode on
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