LK112xx
Low noise low drop voltage regulator with shutdown function
Features
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Output current up to 150 mA
Low dropout voltage (350 mV at I
OUT
= 50 mA)
Very low quiescent current: 0.1 µA in OFF
mode and max. 250 µA in ON mode at
I
OUT
= 0 mA
Low output noise: typ 30 µV at I
OUT
= 60 mA
and 10 Hz < f < 80 kHz
Wide range of output voltages
Internal current and thermal limit
Operative input voltage from:
V
OUT
+ 0.5 to 14 V (for V
OUT
> 2 V)
or from 2.5 V to 14 V (for V
OUT
< 2 V)
The LK112xx has a very low quiescent current in
ON MODE while in OFF MODE the I
q
is reduced
down to 100 nA max. The internal thermal
shutdown circuitry limits the junction temperature
to below 150 °C. The load current is internally
monitored and the device will shutdown in the
presence of a short circuit or overcurrent
condition at the output.
SOT23-5L
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Description
The LK112xx is a low dropout linear regulator with
a built in electronic switch. The internal switch can
be controlled by TTL or CMOS logic levels. The
device is ON state when the control pin is pulled
to a logic high level. An external capacitor can be
used connected to the noise bypass pin to lower
the output noise level to 30 µVrms. An internal
PNP pass transistor is used to achieve a low
dropout voltage.
Table 1.
Device summary
Part numbers
LK112XX14
LK112XX15
LK112XX18
LK112XX19
LK112XX20
LK112XX22
LK112XX23
LK112XX24
LK112XX25
LK112XX26
LK112XX29
LK112XX31
LK112XX33
LK112XX34
LK112XX35
LK112XX37
LK112XX39
LK112XX41
LK112XX42
LK112XX43
LK112XX44
LK112XX45
LK112XX46
LK112XX48
LK112XX49
LK112XX50
LK112XX60
LK112XX80
July 2008
Rev 15
1/17
www.st.com
17
Contents
LK112xx
Contents
1
2
3
4
5
6
7
8
Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Pin configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Typical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Order codes
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
2/17
Pin configuration
LK112xx
2
Figure 2.
Pin configuration
Pin connection (top view)
Table 2.
Pin n°
1
2
3
4
5
Pin description
Symbol
SHDN
GND
Bypass
OUT
IN
Note
Shutdown input: disables the regulator when is connected to GND or to positive
voltage less than 0.6 V
Ground pin: Internally connected to the die attach flag to decrease the total thermal
resistance and increase the package ability to dissipate power.
Bypass pin: bypass with 0.1 µF to improve the V
REF
thermal noise performances.
Output port
Input port
4/17
LK112xx
Maximum ratings
3
Table 3.
Maximum ratings
Absolute maximum ratings
Parameter
DC input voltage
DC input voltage
Output current
Storage temperature range
Operating junction temperature range
Value
16
16
Internally limited
-55 to 150
-40 to 125
°C
°C
Unit
V
V
Symbol
V
I
V
SHDN
I
O
T
STG
T
OP
Table 4.
Symbol
R
thJC
R
thJA
Thermal data
Parameter
Thermal resistance junction-case
Thermal resistance junction-ambient
SOT23-5L
81
255
Unit
°C/W
°C/W
5/17
Microcontroller MCU
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