This is information on a product in full production.
February 2014 DocID8059 Rev 12 1/17
LK112S
Low noise and low drop voltage regulator with shutdown function
Datasheet
-
production data
Features
•Output current up to 200 mA
•Low-dropout voltage (500 mV max. at I
OUT
=
200 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
•V
OUT
tolerance ± 2% (at 25 °C)
•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)
Description
The LK112S is a low-dropout linear regulator with
shutdown function. The internal switch can be
controlled b y TTL or CMOS logic levels. The
device is ON when the control pin is pulled to a
high logic level. An external capacitor can be
connected to the noise bypass pin to reduce the
output noise level to 30 µVrms. An internal PNP
pass transistor is used to achieve a low-dropout
voltage.
The LK112S has a very low quiescent current in
ON mode while in OFF mode the I
q
is reduced to
100 nA max. The internal thermal shutdown
circuitry limits the junction temperature below
150 °C. The load current is internally monitored
and in the presence of a short-circuit or
overcurrent conditions at the output, the device
shuts down.
SOT23-5L
Table 1. Device summary
Part number Output voltage
LK112SM18TR 1.8 V
LK112SM33TR 3.3 V
LK112SM50TR 5.0 V
www.st.com
Contents LK112S
2/17 DocI D8059 Rev 12
Contents
1 Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2 Pin configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3 Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
4 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
5 Typical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
6 Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
7 Packaging mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
8 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
DocID8059 Rev 12 3/17
LK112S Diagram
17
1 Diagram
Figure 1. Schematic diag ram
Pin configuration LK112S
4/17 DocI D8059 Rev 12
2 Pin configuration
Figure 2. Pin connection (top view)
Table 2.
Pin description
Pin n° Symbol Note
1 SHDN Shutdown input disables the regulator when it is connected to GND or to a positive
voltage lower than 0.6 V
2GND
Ground pin: internally connected to the die attach flag to decrease the total thermal
resistance and increase the package ability to dissipate power
3 Bypass Bypass pin: 0.1 µF bypass to improve the
thermal noise performance
4 OUT Output port
5 IN Input port
DocID8059 Rev 12 5/17
LK112S Maximum ratings
17
3 Maximum ratings
Table 3. Absolute maximum ratings
Symbol Parameter Value Unit
V
I
DC input voltage 16 V
V
SHDN
DC input voltage 16 V
I
O
Output current Internally limited
T
STG
Storage temperature range -55 to 150 °C
T
OP
Operating junction temperature range -40 to 125 °C
Table 4. Thermal data
Symbol Parameter SOT23-5L Unit
R
thJC
Thermal resistance junction-case 81 °C/W
R
thJA
Thermal resistance junction-ambient 255 °C/W
Ele ctrical characteristics LK112S
6/17 DocI D8059 Rev 12
4 Electrical characteristics
T
J
= 25 °C, V
IN
= V
OUT
+1 V, I
OUT
= 0 mA, V
SHDN
= 1.8 V, C
I
= 1 µF, C
O
= 2.2 µF, C
BYPASS
=
0.1 µF unless otherwise specified.
Note: For versions with an output voltage lower than 2 V VIN = 2.4 V
Table 5. LK112S electrical characteristics
Symbol Parameter Test conditions Min. Typ. Max. Unit
I
d
Quiescent curren t ON mode (except I
SHDN
) 175 250 µA
OFF mode, V
I
= 8 V, V
SHDN
= 0 V 0 0.1 µA
V
O
Output voltage I
O
= 30 mA -2 +2 %
ΔV
O
Line regulation V
I
= V
O
+1 V to V
O
+6 V, V
O
≤ 5.6 V 0.7 20 mV
V
I
= V
O
+1 V to V
O
+6 V, V
O
> 5.6 V 0.8 40 mV
ΔV
O
Load regulation I
O
= 1 to 60 mA 15 30 mV
I
O
= 1 to 200 mA 30 90 mV
V
d
Dropout voltage I
O
= 60 mA 0.17 0.24 V
I
O
= 200 mA
(1)
0.35 0.5 V
I
SC
Short-circuit current 200 mA
SVR Supply vo ltage rejection V
I
= V
O
+1.5 V, C
BYP
= 0.1 µF
C
O
= 10 µF, f = 400 Hz, I
O
= 30 mA 55 dB
eN Output noise voltage B= 10 Hz to 80 kHz, C
BYP
= 0.1 µF
C
O
= 10 µF, V
I
= V
O
+1.5 V, I
O
= 60 mA 30 µVrms
I
SHDN
Shutdown input current V
SHDN
= 1.8 V, output ON 12 35 µA
V
SHDN
Shutd ow n inp ut logi c Output ON 1.8 V
Output OF F 0.6
ΔV
O
/T
J
Output voltage
temperature coefficient I
O
= 10 mA 0.09 mV/°C
1. For versions with an output voltage higher than 2.1 V only.
DocID8059 Rev 12 7/17
LK112S Typical ch ara cter ist ics
17
5 Typical characteristics
(Unless otherwise specified, T
J
= 25 °C, C
I
= 1 µF, C
O
= 2.2 µF, C
BYP
= 100 nF)
Figure 3. Output voltage vs temperature
V
out
=2.5 V Figure 4. Output voltage vs temperature
V
out
=3.8 V
Figure 5. Line regulation vs temperature Figure 6. Load regulation vs temperature
Typical characteristics LK112S
8/17 DocI D8059 Rev 12
Figure 7. Dropout voltage vs temperature Figure 8. Short-circuit current vs dropout
voltage
Figure 9. Output voltage vs input voltage Figure 10. Shutdown voltage vs temperature
Figure 11. Shutdown current vs shutdown
voltage Figure 12. Supply voltage rejection vs
temperature
2.5 V
2 V
30 mA
DocID8059 Rev 12 9/17
LK112S Typical ch ara cter ist ics
17
Figure 13. Supply voltage rejection vs output
current Figure 14. Supply voltage rejection vs
frequency
Figure 15. Supply volt age rejection vs
temperature Figure 16. Shutdown current vs temperature
Figure 17. Quiescent current vs input voltage Figure 18. Quiescent current vs shutdown
voltage
Typical characteristics LK112S
10/17 DocID8059 Rev 12
Figure 19. Quiescent current vs temperature Figure 20. Reverse current vs reverse voltage
Figure 21. Stability Figure 22. Noise spectrum
Figure 23. Start-up transient C
BYP
=10 nF Figure 24. Start-up transient C
BYP
=100 nF
V
I
=3.5V, V
O
=2.5V, V
SHDN
= 0 to 1.8V, R
L
=2.5kΩ, C
I
=1µF,
C
O
=4.7µF, C
BYP
=10nF
V
I
=3.5V, V
O
=2.5V, V
SHDN
= 0 to 1.8V, R
L
=68Ω, C
I
=1µF,
C
O
=4.7 µF, C
BYP
=100nF
DocID8059 Rev 12 11/17
LK112S Typical ch ara cter ist ics
17
Figure 25. Line transient Co=100 µF Figure 26. Line transient Co=10 µF
V
I
=3.5 to 4 .5 V, V
O
=2.5V, V
SHDN
= 1.8V, I
O
=30mA, no C
I
,
C
O
=100µF, C
BYP
=10nF, t
s
=t
f
=2µs
V
I
=3.5 to 4.5V, V
O
=2.5V, V
SHDN
= 1.8V, I
O
=30mA, no C
I
,
C
O
=10µF, C
BYP
=10nF, t
s
=t
f
=2µs
Figure 27. Line transient Co =1 µF Figure 28. Load transient Vo=2.5 V, Co=2.2 µF
V
I
=3.5 to 4 .5 V, V
O
=2.5V, V
SHDN
= 1.8V, I
O
=30mA, no C
I
,
C
O
=1µF, C
BYP
=1n F, t
s
=t
f
=2µs
V
I
=3.5V, V
O
=2.5V, V
SHDN
= 1.8V, I
O
=50 to 100mA, C
I
=1µF,
C
O
=2.2 µF, C
BYP
=10 nF, t
s
=t
f
=250ns
Figure 29. Load transient Vo=2.5 V, Co=10 µF Figure 30. Load transient Vo=3.8 V,Co=2.2 µF
V
I
=3.5V, V
O
=2.5V, V
SHDN
= 1.8V, I
O
=50 to 100mA, C
I
=1µF,
C
O
=10µF, C
BYP
=100nF, t
s
=t
f
=250ns
V
I
=4.8V, V
O
=3.8V, V
SHDN
= 1.8V, I
O
=50 to 100mA, C
I
=1µF,
C
O
=2.2 µF, C
BYP
=10 nF, t
s
=t
f
=250ns
Package mechanical data LK112S
12/17 DocID8059 Rev 12
6 Package mechanical data
In order to meet environmental requirements, ST offers these devices in different grades of
ECOPACK
®
packages, depending on their level of environmental compliance. ECOPACK
®
specifications, grade definitions and product status are available at: www.st.com.
ECOPACK
®
is an ST trademark.
Figure 31. SOT23-5L mechanical drawings
BN
DocID8059 Rev 12 13/17
LK112S Package mechanical data
17
Figure 32. SOT23-5L recommended footprint (dimensions in mm)
Table 6. SOT23-5L mechanical data
Dim. mm
Min. Typ. Max.
A0.90 1.45
A1 0 0.15
A2 0.90 1.30
b0.30 0.50
c2.09 0.20
D2.95
E1.60
e0.95
H2.80
L0.30 0.60
θ08
BN
Packagi ng mechan ic al data LK112S
14/17 DocID8059 Rev 12
7 Packaging mechanical data
Figure 33.SOT23-5L tape and reel drawings
DocID8059 Rev 12 15/17
LK112S Packaging mechanical data
17
Figure 34.SOT23-5L tape and reel mechanical data
Dim. mm
Min. Typ. Max.
A180
C 12.8 13.0 13.2
D20.2
N60
T14.4
Ao 3.13 3.23 3.33
Bo 3.07 3.17 3.27
Ko 1.27 1.37 1.47
Po 3.9 4.0 4.1
P 3.9 4.0 4.1
Revision history LK112S
16/17 DocID8059 Rev 12
8 Revision history
Table 7. Document revision history
Date Revision Changes
31-Aug-2004 3 Mistak e on fig. 19.
31-Jan-2005 4 Change maturity code.
12-Jun-2006 5 Order codes updated.
17-Oct-2006 6 The T
OP
value on table 2 updated.
20-Jul-2007 7 Add Table 1 in cover page.
21-Sep-2007 8 Fea ture s updated .
11-Dec-2007 9 Modified: Table 6.
12-Feb-2008 10 Modified: Table 6.
10-Jul-2008 11 Modified: Table 1 and Table 6.
11-Feb-2014 12
Part number LK112Sxx changed to LK112S.
Updated the title and the Description in cover page, Table 2: Pin description,
Section 5: Typical characteristics and Section 6: Package mechanical data.
Added Section 7: Packaging mechanical data.
Minor text changes.
DocID8059 Rev 12 17/17
LK112S
17
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