LK112xx
Low noise low drop voltage regulator with shutdown function
Features
■Output current up to 150 mA
■Low dropout voltage (350 mV at IOUT = 50 mA)
■ Very low quiescent current: |
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– 0.1 µA in OFF mode and max. 250 µA in |
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ON mode at IOUT = 0 mA |
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■ Low output noise: |
SOT23-5L |
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– typ. 30 µV at IOUT = 60 mA and 10 Hz < f < |
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80 kHz |
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■ Wide range of output voltages |
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■ Internal current and thermal limit |
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■ Operative input voltage from: |
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– VOUT + 0.5 to 14 V (for VOUT > 2 V) or from |
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2.5 V to 14 V (for VOUT < 2 V) |
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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. The LK112xx 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 |
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Part numbers |
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LK112XX15 |
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LK112XX25 |
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LK112XX50 |
LK112XX60 |
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LK112XX18 |
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LK112XX33 |
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LK112XX55 |
LK112XX80 |
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February 2011 |
Doc ID 7362 Rev 16 |
1/17 |
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www.st.com |
Contents |
LK112xx |
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Contents
1 |
Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . |
. 3 |
2 |
Pin configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . |
. 4 |
3 |
Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . |
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4 |
Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . |
6 |
5 |
Typical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . |
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6 |
Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . |
12 |
7 |
Order codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . |
15 |
8 |
Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . |
16 |
2/17 |
Doc ID 7362 Rev 16 |
LK112xx |
Diagram |
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Doc ID 7362 Rev 16 |
3/17 |
Pin configuration |
LK112xx |
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Table 2. |
Pin description |
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Pin n° |
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Symbol |
Note |
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1 |
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SHDN |
Shutdown input: disables the regulator when is connected to GND or to positive |
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voltage less than 0.6 V |
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2 |
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GND |
Ground pin: Internally connected to the die attach flag to decrease the total thermal |
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resistance and increase the package ability to dissipate power. |
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3 |
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Bypass |
Bypass pin: bypass with 0.1 µF to improve the VREF thermal noise performances. |
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OUT |
Output port |
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5 |
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IN |
Input port |
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4/17 |
Doc ID 7362 Rev 16 |
LK112xx |
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Maximum ratings |
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3 |
Maximum ratings |
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Table 3. |
Absolute maximum ratings |
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Symbol |
Parameter |
Value |
Unit |
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VI |
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DC input voltage |
16 |
V |
VSHDN |
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DC input voltage |
16 |
V |
IO |
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Output current |
Internally limited |
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TSTG |
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Storage temperature range |
-55 to 150 |
°C |
TOP |
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Operating junction temperature range |
-40 to 125 |
°C |
Table 4. |
Thermal data |
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Symbol |
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Parameter |
SOT23-5L |
Unit |
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RthJC |
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Thermal resistance junction-case |
81 |
°C/W |
RthJA |
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Thermal resistance junction-ambient |
255 |
°C/W |
Doc ID 7362 Rev 16 |
5/17 |
Electrical characteristics |
LK112xx |
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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. |
Electrical characteristics for LK112 |
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Symbol |
Parameter |
Test conditions |
Min. |
Typ. |
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Max. |
Unit |
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Iq |
Quiescent current |
ON MODE (except ISHDN) |
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175 |
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250 |
µA |
OFF MODE, VI = 8V, VSHDN = 0V |
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0 |
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0.1 |
µA |
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VO |
Output voltage |
IO = 30mA |
(see table) |
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VO |
Line regulation |
VI = VO+1V to VO+6V, VO ≤ 5.6V |
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0.7 |
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20 |
mV |
VI = VO+1V to VO+6V, VO > 5.6V |
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0.8 |
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40 |
mV |
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VO |
Load regulation |
IO = 1 to 60mA |
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15 |
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30 |
mV |
IO = 1 to 150mA |
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25 |
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90 |
mV |
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I = 60 mA (1) |
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0.17 |
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0.24 |
V |
Vd |
Dropout voltage |
O |
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I = 150 mA (1) |
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0.29 |
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0.35 |
V |
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O |
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IO |
Output current limit |
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150 |
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mA |
SVR |
Supply voltage rejection |
VI = VO+1.5V, CBYP = 0.1µF |
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55 |
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dB |
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CO = 10µF, f = 400Hz, IO = 30mA |
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eN |
Output noise voltage |
B= 10Hz to 80kHz, CBYP = 0.1µF |
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30 |
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µVrms |
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CO = 10µF, VI = VO+1.5V, IO = 60mA |
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ISHDN |
Shutdown input current |
VSHDN = 1.8V, Output ON |
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12 |
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35 |
µA |
VSHDN |
Shutdown input logic |
Output ON |
1.8 |
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V |
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Output OFF |
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0.6 |
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VO/TJ |
Output voltage |
IO = 10mA |
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0.09 |
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mV/°C |
temperature coefficient |
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1. Only for version with output voltage more than 2.1 V |
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Note: |
For version with output voltage less than 2 V, VIN = 2.4 V. |
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6/17 |
Doc ID 7362 Rev 16 |