LK112S
Low noise and low drop voltage regulator with shutdown function
Datasheet - production data
Description
The LK112S is a low-dropout linear regulator with
shutdown function. The internal switch can be
controlled by 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.
SOT23-5L
Features
• Output current up to 200 mA
• Low-dropout voltage (500 mV max. at IOUT =
200 mA)
• Very low quiescent current: 0.1 µA in OFF
mode and max. 250 µA in ON mode at IOUT = 0
mA
The LK112S has a very low quiescent current in
ON mode while in OFF mode the Iq 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.
• Low output noise: typ. 30 µV at IOUT = 60 mA
and 10 Hz < f < 80 kHz
• Wide range of output voltages
• Internal current and thermal limit
• VOUT tolerance ± 2% (at 25 °C)
• Operative input voltage from: VOUT + 0.5 to 14
V (for VOUT > 2 V) or from 2.5 V to 14 V (for
VOUT < 2 V)
Table 1. Device summary
Part number
Output voltage
LK112SM18TR
1.8 V
LK112SM33TR
3.3 V
LK112SM50TR
5.0 V
February 2014
This is information on a product in full production.
DocID8059 Rev 12
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www.st.com
Contents
LK112S
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
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LK112S
1
Diagram
Diagram
Figure 1. Schematic diagram
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Pin configuration
2
LK112S
Pin configuration
Figure 2. Pin connection (top view)
Table 2. Pin description
4/17
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
2
GND
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
4
OUT
5
IN
Bypass pin: 0.1 µF bypass to improve the thermal noise performance
Output port
Input port
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LK112S
Maximum ratings
3
Maximum ratings
Table 3. Absolute maximum ratings
Symbol
Parameter
Value
Unit
VI
DC input voltage
16
V
VSHDN
DC input voltage
16
V
IO
Output current
Internally limited
TSTG
Storage temperature range
-55 to 150
°C
TOP
Operating junction temperature range
-40 to 125
°C
Table 4. Thermal data
Symbol
Parameter
SOT23-5L
Unit
RthJC
Thermal resistance junction-case
81
°C/W
RthJA
Thermal resistance junction-ambient
255
°C/W
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Electrical characteristics
4
LK112S
Electrical characteristics
TJ = 25 °C, VIN = VOUT +1 V, IOUT = 0 mA, VSHDN = 1.8 V, CI = 1 µF, CO = 2.2 µF, CBYPASS =
0.1 µF unless otherwise specified.
Table 5. LK112S electrical characteristics
Symbol
Parameter
Id
Quiescent current
VO
Output voltage
ΔVO
Line regulation
ΔVO
Load regulation
Vd
Dropout voltage
ISC
Short-circuit current
Test conditions
Min.
ON mode (except ISHDN)
OFF mode, VI = 8 V, VSHDN = 0 V
IO = 30 mA
Typ.
Max.
Unit
175
250
µA
0
0.1
µA
+2
%
-2
VI = VO+1 V to VO+6 V, VO ≤ 5.6 V
0.7
20
mV
VI = VO+1 V to VO+6 V, VO > 5.6 V
0.8
40
mV
IO = 1 to 60 mA
15
30
mV
IO = 1 to 200 mA
30
90
mV
0.17
0.24
V
0.35
0.5
V
IO = 60 mA
IO = 200
mA(1)
200
mA
Supply voltage rejection
VI = VO+1.5 V, CBYP = 0.1 µF
CO = 10 µF, f = 400 Hz, IO = 30 mA
55
dB
Output noise voltage
B= 10 Hz to 80 kHz, CBYP = 0.1 µF
CO = 10 µF, VI = VO+1.5 V, IO = 60 mA
30
µVrms
ISHDN
Shutdown input current
VSHDN = 1.8 V, output ON
12
VSHDN
Shutdown input logic
ΔVO/TJ
Output voltage
temperature coefficient
SVR
eN
Output ON
6/17
µA
1.8
V
Output OFF
IO = 10 mA
1. For versions with an output voltage higher than 2.1 V only.
Note:
35
For versions with an output voltage lower than 2 V VIN = 2.4 V
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0.6
0.09
mV/°C
LK112S
5
Typical characteristics
Typical characteristics
(Unless otherwise specified, TJ = 25 °C, CI = 1 µF, CO = 2.2 µF, CBYP = 100 nF)
Figure 3. Output voltage vs temperature
Figure 4. Output voltage vs temperature
Vout=2.5 V
Vout=3.8 V
Figure 5. Line regulation vs temperature
Figure 6. Load regulation vs temperature
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Typical characteristics
LK112S
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
2.5 V
2V
30 mA
Figure 11. Shutdown current vs shutdown
voltage
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Figure 12. Supply voltage rejection vs
temperature
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LK112S
Typical characteristics
Figure 13. Supply voltage rejection vs output
current
Figure 14. Supply voltage rejection vs
frequency
Figure 15. Supply voltage rejection vs
temperature
Figure 16. Shutdown current vs temperature
Figure 17. Quiescent current vs input voltage
Figure 18. Quiescent current vs shutdown
voltage
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Typical characteristics
LK112S
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 CBYP=10 nF
Figure 24. Start-up transient CBYP=100 nF
VI=3.5V, VO=2.5V, VSHDN= 0 to 1.8V, RL=2.5kΩ, CI=1µF,
CO=4.7µF, CBYP=10nF
10/17
VI=3.5V, VO=2.5V, VSHDN= 0 to 1.8V, RL=68Ω, CI=1µF,
CO=4.7µF, CBYP=100nF
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LK112S
Typical characteristics
Figure 25. Line transient Co=100 µF
VI=3.5 to 4.5V, VO=2.5V, VSHDN= 1.8V, IO=30mA, no CI,
CO=100µF, CBYP=10nF, ts=tf=2µs
Figure 27. Line transient Co=1 µF
VI=3.5 to 4.5V, VO=2.5V, VSHDN= 1.8V, IO=30mA, no CI,
CO=1µF, CBYP=1nF, ts=tf=2µs
Figure 29. Load transient Vo=2.5 V, Co=10 µF
VI=3.5V, VO=2.5V, VSHDN= 1.8V, IO=50 to 100mA, CI=1µF,
CO=10µF, CBYP=100nF, ts=tf=250ns
Figure 26. Line transient Co=10 µF
VI=3.5 to 4.5V, VO=2.5V, VSHDN= 1.8V, IO=30mA, no CI,
CO=10µF, CBYP=10nF, ts=tf=2µs
Figure 28. Load transient Vo=2.5 V, Co=2.2 µF
VI=3.5V, VO=2.5V, VSHDN= 1.8V, IO=50 to 100mA, CI=1µF,
CO=2.2µF, CBYP=10nF, ts=tf=250ns
Figure 30. Load transient Vo=3.8 V,Co=2.2 µF
VI=4.8V, VO=3.8V, VSHDN= 1.8V, IO=50 to 100mA, CI=1µF,
CO=2.2µF, CBYP=10nF, ts=tf=250ns
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Package mechanical data
6
LK112S
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
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LK112S
Package mechanical data
Table 6. SOT23-5L mechanical data
mm
Dim.
Min.
Typ.
Max.
A
0.90
1.45
A1
0
0.15
A2
0.90
1.30
b
0.30
0.50
c
2.09
0.20
D
2.95
E
1.60
e
0.95
H
2.80
L
0.30
0.60
θ
0
8
Figure 32. SOT23-5L recommended footprint (dimensions in mm)
BN
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Packaging mechanical data
7
LK112S
Packaging mechanical data
Figure 33.SOT23-5L tape and reel drawings
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LK112S
Packaging mechanical data
Figure 34.SOT23-5L tape and reel mechanical data
mm
Dim.
Min.
Typ.
A
Max.
180
C
12.8
D
20.2
N
60
13.0
T
13.2
14.4
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
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Revision history
8
LK112S
Revision history
Table 7. Document revision history
Date
Revision
31-Aug-2004
3
Mistake on fig. 19.
31-Jan-2005
4
Change maturity code.
12-Jun-2006
5
Order codes updated.
17-Oct-2006
6
The TOP value on table 2 updated.
20-Jul-2007
7
Add Table 1 in cover page.
21-Sep-2007
8
Features 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.
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.
11-Feb-2014
16/17
Changes
DocID8059 Rev 12
LK112S
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