The LK112S is a low d ropout li near regul ator 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 30µV
. An internal PNP
rms
pass transistor is used t o achieve a low dropout
voltage.
SOT23-5L
The LK112S has a very low quiescent current in
ON MODE while in OFF MODE the Iq is reduced
down to 100nA max. The internal thermal
shutdown circuitry limits the juntion 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.
SCHEMATIC DIAGRAM
1/11February 2003
Page 2
LK112S SERIES
ABSOLUTE MAXIMUM RATINGS
SymbolParameter²ValueUnit
V
V
SHDN
I
T
T
CONNECTION DIAGRAM (top view) PIN DESCRIPTION
DC Input Voltage
I
Shutdown Input Voltage
Output Current
O
Storage Temperature Range
stg
Operating Junction Temperature Range
op
SOT23-5L
16V
16V
Internally limited
-55 to +150°C
-30 to +80°C
Pin N° SymbolName and Function
1SHDN Shutdown Input: Disables the
regulator when is connected to GND
or to positive voltage less than 0.6V
2GNDGround Pin: Internally connected to
the die attach flag to decrease the
total thermal resistance and increase
the package ability to dissipate
power.
3Bypass Bypass Pin: Bypass with 0.1µF to
improve the Vref thermal noise
performances.
4OU TOutput Port
5INInput Port
ELECTRICAL CHARACTERISTICS FOR LK112 (T
V
=1.8V, CI = 1 µF, CO = 2.2µ F, C
SHDN
BYPASS
= 0.1µF unless otherwise specified)
= 25°C, VIN=V
j
+1V (see Note 1), I
OUT
OUT
=0mA,
SymbolParameterTest ConditionsMin.Typ.Max.Unit
I
Quiescent CurrentON MODE (except I
d
OFF MODE V
Output VoltageIO = 30mA(see table)
V
O
∆V
∆V
SVRSupply Voltage RejectionV
Line RegulationVI = VO+1V to VO+6V,VO ≤ 5.6V0.720mV
O
= VO+1V to VO+6V,VO > 5.6V0.840mV
V
I
Load RegulationIO = 1 to 60mA1530mV
O
= 1 to 200mA3090mV
I
O
V
Dropout VoltageIO = 60 mA (see Note 2)0.170.24V
d
= 200 mA (see Note 2)0.350.5V
I
O
Short Circuit Current200mA
I
SC
= VO+1.5VC
I
C
= 10µFf = 400Hz IO = 30mA
O
eNOutput Noise VoltageB= 10Hz to 80KHz C
C
= 10µFVI = VO+1.5V,IO = 60mA
O
I
SHDN
V
∆V
Note 1: fo r version wi th output vol tage less than 2V VIN=2.4V
Note 2: only for version with output voltage more than 2.1V
Shutdown Input CurrentV
Shutdown Input LogicOutput ON
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