Low noise low drop voltage regulator with shutdown function
Features
■ Output current up to 200 mA
■ Low dropout voltage (500 mV max at
I
= 200 mA)
OUT
■ Very low quiescent current: 0.1 µA in OFF
mode and max 250 µA in ON mode at
I
= 0 mA
OUT
■ Low output noise: typ. 30 µV at I
and 10 Hz < f < 80 kHz
■ Wide range of output voltages
■ Internal current and thermal limit
■ V
■ Operative input voltage from:
tolerance ± 2% (at 25 °C)
OUT
V
+ 0.5 to 14 V (for V
OUT
OUT
or from 2.5 V to 14 V (for V
> 2 V)
OUT
Description
The LK112Sxx 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
OUT
< 2 V)
= 60 mA
LK112Sxx
SOT23-5L
µVrms. An internal PNP pass transistor is used to
achieve a low dropout voltage.
The LK112Sxx has a very low quiescent current
in ON MODE while in OFF MODE the Iq 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.
Table 1. Device summary
Part numbers
LK112SXX13 LK112SXX24 LK112SXX36 LK112SXX45
LK112SXX14 LK112SXX26 LK112SXX37 LK112SXX46
LK112SXX18 LK112SXX28 LK112SXX38 LK112SXX47
LK112SXX19 LK112SXX29 LK112SXX39 LK112SXX48
LK112SXX20 LK112SXX31 LK112SXX41 LK112SXX49
LK112SXX21 LK112SXX33 LK112SXX42 LK112SXX50
LK112SXX22 LK112SXX34 LK112SXX43
LK112SXX23 LK112SXX35 LK112SXX44
July 2008 Rev 11 1/17
www.st.com
17
Contents LK112Sxx
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 Order codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
8 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
2/17
LK112Sxx Diagram
1 Diagram
Figure 1. Schematic diagram
3/17
Pin configuration LK112Sxx
2 Pin configuration
Figure 2. Pin connection (top view)
Table 2. Pin description
Pin n° Symbol Note
1 SHDN
2GND
3 Bypass Bypass Pin: Bypass with 0.1 µF to improve the V
4 OUT Output port
5 IN Input port
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.
thermal noise performances.
REF
4/17
LK112Sxx Maximum ratings
3 Maximum ratings
Table 3. Absolute maximum ratings
Symbol Parameter Value Unit
V
SHDN
T
T
V
I
I
O
STG
OP
DC input voltage 16 V
DC input voltage 16 V
Output current Internally limited
Storage temperature range -55 to 150 °C
Operating junction temperature range -40 to 125 °C
Table 4. Thermal data
Symbol Parameter SOT23-5L Unit
R
thJC
R
thJA
Thermal resistance junction-case 81 °C/W
Thermal resistance junction-ambient 255 °C/W
5/17
Electrical characteristics LK112Sxx
4 Electrical characteristics
Table 5. Electrical characteristics for LK112S (TJ = 25 °C, VIN=V
V
= 1.8 V, CI = 1 µF, CO = 2.2 µF, C
SHDN
BYPASS
= 0.1 µF unless otherwise specified)
OUT
+1 V
(1)
, I
OUT
= 0mA,
Symbol Parameter Test conditions Min. Typ. Max. Unit
I
Quiescent current
d
V
Output voltage IO = 30mA (see table)
O
ΔV
ΔV
Line regulation
O
Load regulation
O
V
Dropout voltage
d
Short circuit current 200 mA
I
SC
SVR Supply voltage rejection
eN Output noise voltage
I
SHDN
Shutdown input current V
ON MODE (except I
(2)
(2)
= 8V, V
I
BYP
OFF MODE, V
V
= VO+1V to VO+6V, VO ≤ 5.6V 0.7 20 mV
I
= VO+1V to VO+6V, VO > 5.6V 0.8 40 mV
V
I
I
= 1 to 60mA 15 30 mV
O
= 1 to 200mA 30 90 mV
I
O
I
= 60 mA
O
I
= 200 mA
O
= VO+1.5V, C
V
I
= 10µF, f = 400Hz, IO = 30mA
C
O
B= 10Hz to 80kHz, C
CO = 10µF, VI = VO+1.5V, IO = 60mA
= 1.8V, Output ON 12 35 µA
SHDN
)175250µA
SHDN
= 0V 0 0.1 µA
SHDN
0.17 0.24 V
0.35 0.5 V
= 0.1µF
= 0.1µF
BYP
55 dB
30 µVrms
Output ON 1.8
V
Shutdown input logic
SHDN
Output OFF 0.6
V
ΔVO/T
1. For version with output voltage less than 2V VIN=2.4V
2. Only for version with output voltage more than 2.1V
Output voltage
J
temperature coefficient
= 10mA 0.09 mV/°C
I
O
6/17
LK112Sxx Typical characteristics
5 Typical characteristics
(Unless otherwise specified, TJ = 25 °C, CI = 1 µF, CO = 2.2 µF, C
Figure 3. Output voltage vs temperature Figure 4. Output voltage vs temperature
Figure 5. Line regulation vs temperature Figure 6. Load regulation vs temperature
= 100 nF)
BYP
Figure 7. Dropout voltage vs temperature Figure 8. Short circuit current vs dropout
voltage
7/17
Typical characteristics LK112Sxx
Figure 9. Output voltage vs input voltage Figure 10. Shutdown voltage vs temperature
Figure 11. Shutdown current vs shutdown
voltage
Figure 13. Supply voltage rejection vs output
current
Figure 12. Supply voltage rejection vs
temperature
Figure 14. Supply voltage rejection vs
frequency
8/17
LK112Sxx Typical characteristics
Figure 15. Supply voltage rejection vs
temperature
Figure 16. Quiescent current vs temperature
Figure 17. Quiescent current vs input voltage Figure 18. Quiescent current vs shutdown
voltage
Figure 19. Quiescent current vs temperature Figure 20. Reverse current vs reverse voltage
9/17
Typical characteristics LK112Sxx
Figure 21. Stability Figure 22. Spectrum noise
Figure 23. Start-up transient Figure 24. Start-up transient
VI=3.5V, VO=2.5V, V
CO=4.7µF, C
Figure 25. Line transient Figure 26. Line transient
BYP
VI=3.5 to 4.5V, VO=2.5V, V
C
=100µF, C
O
= 0 to 1.8V, RL=2.5kΩ, CI=1µF,
SHDN
=10nF
= 1.8V, IO=30mA, no CI,
SHDN
=10nF, ts=tf=2µs
BYP
VI=3.5V, VO=2.5V, V
CO=4.7µF, C
BYP
SHDN
=100nF
VI=3.5 to 4.5V, VO=2.5V, V
C
=10µF, C
O
=10nF, ts=tf=2µs
BYP
= 0 to 1.8V, RL=68Ω, CI=1µF,
SHDN
10/17
= 1.8V, IO=30mA, no CI,
LK112Sxx Typical characteristics
Figure 27. Line transient Figure 28. Load transient
VI=3.5 to 4.5V, VO=2.5V, V
C
=1µF, C
O
Figure 29. Load transient Figure 30. Load transient
VI=3.5V, VO=2.5V, V
CO=10µF, C
=1nF, ts=tf=2µs
BYP
SHDN
=100nF, ts=tf=250ns
BYP
= 1.8V, IO=30mA, no CI,
SHDN
= 1.8V, IO=50 to 100mA, CI=1µF,
VI=3.5V, VO=2.5V, V
C
=2.2µF, C
O
VI=4.8V, VO=3.8V, V
CO=2.2µF, C
BYP
BYP
= 1.8V, IO=50 to 100mA, CI=1µF,
SHDN
=10nF, ts=tf=250ns
= 1.8V, IO=50 to 100mA, CI=1µF,
SHDN
=10nF, ts=tf=250ns
11/17
Package mechanical data LK112Sxx
6 Package mechanical data
In order to meet environmental requirements, ST offers these devices in ECOPACK®
packages. These packages have a lead-free second level interconnect. The category of
second Level Interconnect is marked on the package and on the inner box label, in
compliance with JEDEC Standard JESD97. The maximum ratings related to soldering
conditions are also marked on the inner box label. ECOPACK is an ST trademark.
ECOPACK specifications are available at: www.st.com.
12/17
LK112Sxx Package mechanical data
SOT23-5L mechanical data
mm. mils.
Dim.
Min. Typ. Max. Min. Typ. Max.
A0.90 1.45 35.4 57.1
A1 0.00 0.10 0.0 3.9
A2 0.901.30 35.4 51.2
b 0.35 0.50 13.7 19.7
C0.09 0.20 3.5 7.8
D2.80 3.00 110.2 118.1
E 1.50 1.75 59.0 68.8
e0.95 37.4
H 2.60 3.00 102.3 118.1
L 0.10 0.60 3.9 23.6
7049676D
13/17
Package mechanical data LK112Sxx
Tape & reel SOT23-xL mechanical data
Dim.
Min. Typ. Max. Min. Typ. Max.
A180 7.086
C 12.8 13.0 13.2 0.504 0.512 0.519
D 20.2 0.795
N60 2.362
T 14.4 0.567
Ao 3.133.233.33 0.123 0.127 0.131
Bo 3.07 3.17 3.27 0.120 0.124 0.128
Ko 1.27 1.37 1.47 0.050 0.054 0.0.58
Po 3.9 4.0 4.1 0.153 0.157 0.161
P 3.9 4.0 4.1 0.153 0.157 0.161
mm. inch.
14/17
LK112Sxx Order codes
7 Order codes
Table 6. Order codes
Part number Output voltage V
LK112SM13TR
LK112SM14TR
(1)
(1)
1.3V 1.24V 1.36V 2.4V
1.4V 1.34V 1.46V 2.4V
Min. V
OUT
Max. Test voltage
OUT
LK112SM18TR 1.8V 1.74V 1.86V 2.4V
LK112SM19TR
LK112SM20TR
LK112SM21TR
LK112SM22TR
LK112SM23TR
LK112SM24TR
LK112SM26TR
(1)
(1)
(1)
(1)
(1)
(1)
(1)
1.9V 1.84V 1.96V 2.4V
2.0V 1.94V 2.06V 3.0V
2.1V 2.04V 2.16V 3.1V
2.2V 2.14V 2.26V 3.2V
2.3V 2.24V 2.36V 3.3V
2.4V 2.34V 2.46V 3.4V
2.6V 2.54V 2.66V 3.6V
LK112SM28TR 2.8V 2.74V 2.86V 3.8V
LK112SM29TR
LK112SM31TR
(1)
(1)
2.9V 2.84V 2.96V 3.9V
3.1V 3.04V 3.16V 4.1V
LK112SM33TR 3.3V 3.24V 3.36V 4.3V
LK112SM34TR
LK112SM35TR
LK112SM36TR
LK112SM37TR
LK112SM38TR
LK112SM39TR
LK112SM41TR
LK112SM42TR
LK112SM43TR
LK112SM44TR
LK112SM45TR
LK112SM46TR
LK112SM47TR
LK112SM48TR
LK112SM49TR
(1)
(1)
(1)
(1)
(1)
(1)
(1)
(1)
(1)
(1)
(1)
(1)
(1)
(1)
(1)
3.4V 3.335V 3.465V 4.4V
3.5V 3.435V 3.565V 4.5V
3.6V 3.535V 3.655V 4.6V
3.7V 3.630V 3.770V 4.7V
3.8V 3.725V 3.875V 4.8V
3.9V 3.825V 3.975V 4.9V
4.1V 4.020V 4.180V 5.1V
4.2V 4.120V 4.280V 5.2V
4.3V 4.215V 4.385V 5.3V
4.4V 4.315V 4.485V 5.4V
4.5V 4.410V 4.590V 5.5V
4.6V 4.510V 4.690V 5.6V
4.7V 4.605V 4.795V 5.7V
4.8V 4.705V 4.895V 5.8V
4.9V 4.800V 5.000V 5.9V
LK112SM50TR 5.0V 4.900V 5.100V 6.0V
1. Available on request.
15/17
Revision history LK112Sxx
8 Revision history
Table 7. Document revision history
Date Revision Changes
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 Ta b le 1 in cover page.
21-Sep-2007 8 Features updated.
11-Dec-2007 9 Modified: Ta bl e 6 .
12-Feb-2008 10 Modified: Table 6 on page 15.
10-Jul-2008 11 Modified: Table 1 on page 1 and Table 6 on page 15.
16/17
LK112Sxx
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