LR12
LR12
High Input Voltage
Adjustable 3-Terminal Linear Regulator
Features
General Description
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The Supertex LR12 is a high voltage, low output current, adjustable
linear regulator. It has a wide operating input voltage range of
13.2V to 100V. The output voltage can be adjusted from 1.20V to
88V provided that the input voltage is at least 12V greater than the
output voltage. The output voltage can be adjusted by means of
two external resistors R1 and R2 as shown in the typical application
circuits. The LR12 regulates the voltage difference between VOUT
and ADJ pins to a nominal value of 1.20V. The 1.20V is amplified
by the external resistor ratio R1 and R2. An internal constant bias
current of typically 10µA is connected to the ADJ pin. This
increases VOUT by a constant voltage of 10µA times R2.
13.2V to 100V Input Voltage Range
Stable with 100nF output capacitor
Adjustable 1.20V to 88V output regulation
5% reference voltage tolerance
Output current limiting, 50mA min.
10µA typical ADJ current
Over temperature protection
Available in 3 different packages
The LR12 has current limiting and temperature limiting. The
output current limit is 100mA maximum and the minimum
temperature limit is 125°C. An output short circuit current will
therefore be limited to 100mA maximum. When the junction
temperature reaches its temperature limit, the output current and/
or output voltage will decrease to keep the junction temperature
from exceeding its temperature limit. For SMPS start-up circuit
applications, the LR12 turns off when an external voltage greater
than the output voltage of the LR12 is applied to VOUT of the LR12.
To maintain stability, a bypass capacitor of 100nF or larger and a
minimum DC output current of 500µA are required.
Applications
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DC/DC SMPS startup circuits
Adjustable high voltage constant current sources
Industrial Controls
Motor Controls
Battery Powered Systems
Power Supplies
The device is available in TO-92, SO-8, and TO-252 (D-PAK)
packages.
Telecom Applications
LED Drivers
Automotive Applications
LR12 Typical Application
*
VOUT
1.2V to 88V
VIN
VIN
13.2V to
100V
V
OUT
ADJ
R1
LR12
C2
C1
RLOAD
R2
*Required for conditions where VIN is less than VOUT.
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LR12
Ordering Information
Package Options
SO-8
TO-2521
TO-92
LR12LG
LR12LG-G
LR12K4
LR12K4-G
LR12N3
LR12N3-G
Notes:
1. TO-252 supplied on 2000 piece carrier tape reels only
-G indicates package is RoHS compliant “Green”
Pin Configurations
VOUT
Absolute Maximum Ratings
VIN-ADJ
ADJ
NC
1
8
VOUT
2
7
NC
VIN
3
6
4
5
VOUT
VOUT
VOUT
ADJ
TO-252
(D-PAK)
SO-8
-0.5V to +120V
-10V to +10V
Operating Ambient Temperature Range
-40°C to +85°C
Operating Junction Temperature Range
-40°C to +125°C
Storage Temperature Range
-65°C to +150°C
TO-92
ADJ
-0.5V to +120V
VOUT
VIN – VOUT
VIN
VOUT-ADJ
VIN
Electrical Characteristics
Test conditions unless otherwise specified: -40°C < TA < 85°C.
Symbol
Parameter
Min
VIN - VOUT
Input to Output Voltage Difference
12
VOUT
Overall Output Voltage Regulation
1.14
∆VOUT
Typ
Max
Units
98.8
V
1.20
1.26
V
Line Regulation
0.003
0.03
%/V
15V<VIN<100V, VOUT = 5V, IOUT = 0.5mA
∆VOUT
Load Regulation
1.4
3.0
%
VIN = 15V, VOUT = 5V, 0.5mA<IOUT<50mA
∆VOUT
Temperature Regulation
+1
%
-1
Test Conditions
13.2V<VIN<100V, R1 = 2.4KΩ, R2 = 0
VIN = 15V, VOUT = 5V, IOUT = 10mA,
-40°C<TA<85°C
IOUT
Output Current Limit
IOUT
Output Current Limit
IOUT
Minimum Output Current
IADJ
Adjust Output Current
C2
Minimum Output Load Capacitance
50
mA
TJ < 85°C, VIN - VOUT = 12V
0.5
mA
TJ > 125°C, VIN - VOUT = 100V
mA
Includes R1 and load current
0.5
5
10
100
DVOUT/DVIN Ripple Rejection Ratio
50
TLIMIT
125
Junction Temperature Limit
100
15
µA
nF
60
dB
120Hz, VOUT = 5V
°C
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LR12
Thermal Characteristics
Power Dissipation
@ TA=25°C
θJC
θJA
°C/W
°C/W
TO-92
0.6W
125
170
SO-8
1.8W
—
55†
TO-252
2.0W
6.25
50†
Package
†
Mounted on FR4 board, 25mm x 25mm x 1.57mm.
Significant PD increase possible on ceramic substrate.
Functional Block Diagram
VIN
LR12
Pass
Element
Overtemp &
Overcurrent
VOUT
6.5V
1KΩ
1.2V
10μA
ADJ
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LR12
Typical Application Circuits
*
V
VIN=17V to 100V
VOUT =5.0V
V
IN
OUT
ADJ
R1
6.04KΩ
±1%
LR12
C1
C2
100nF
R2
18.2KΩ
±1%
VOUT = 1.20V 1+ R2 + IADJ R2
R1
Figure 1: High Input Voltage, 5.0V Output Linear Regulator
* Required for conditions where VIN is less than VOUT.
VIN=15V to 100V
+
VAuxiliary
Vout1
-
LR12
VIN
+
V
OUT
ADJ
Vout2
-
Vcc
FB
PWM IC
Figure 2: SMPS Start-Up Circuit
IOUT =
LR12
+
VIN
1.20V
R
VOUT
R
ADJ
VIN = 15V
to 100V
100nF
-
Figure 3: High Voltage Adjustable Constant Current Source
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LR12
Typical Performance Curves
Temperature Variation
1.30
1.25
LR12
ADJ
2.4KΩ
13.2V
100nF
VOUT (V)
VOUT=1.2V
VIN
1.20
1.15
1.10
1.05
1.00
-50
-25
0
25
50
75
100
125
o
T(junction) ( C)
Load Regulation
5.30
5.25
V
VIN
OUT
= 5.0V
IOUT
5.20
LR12
5.15
6.04KΩ
±1%
100nF
25V
VOUT (V)
ADJ
RLOAD
18.2KΩ
±1%
5.10
5.05
5.00
4.95
4.90
4.85
4.80
0
5
10
15
20
25
30
35
40
45
50
IOUT (mA)
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LR12
Typical Performance Curves
VOUT vs. VIN
6
V
V
IN
= 5.0V
5
OUT
ADJ
VOUT (V)
LR12
6.04KΩ
±1%
100nF
0V to 50V
1KΩ
18.2KΩ
±1%
4
3
2
1
0
0
20
40
60
80
100
VIN (V)
Ripple Rejection
-65
IOUT
Ripple Rejection Ratio (dB)
VOUT = 5.0V
VIN
LR12
20VP-P
@ 120Hz
ADJ
65V
6.04KΩ
±1%
100nF
RLOAD
18.2KΩ
±1%
-64
-63
-62
-61
-60
0
10
20
30
40
50
IOUT (mA)
Current Limit
100
IC (mA)
90
80
70
60
50
-40
-20
0
20
40
60
80
100
o
Temperature ( C)
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LR12
Typical Performance Curves
Load Transient Response
V
SW
VOUT=5.0V
IN
Closed
LR12
ADJ
6.04KΩ
±1%
SW
100nF
25V
Open
10KΩ
18.2KΩ
±1%
509Ω
VOUT
200mV/div
Load Transient Response, Load = 509Ω
Line Transient Response
100V
VOUT
VIN
VIN
LR12
0V
ADJ
6.04KΩ
±1%
100nF
10KΩ
18.2KΩ
±1%
VIN
50V/div
VOUT
5V/div
Line Turn On/Off Response
VIN
50V/div
VIN
50V/div
VOUT
5V/div
VOUT
5V/div
Line Power Up Transient
Line Power Down Transient
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LR12
3 Lead TO-92 Plastic Package (N3)
0.190 ± 0.020
(4.826 ± 0.508)
D
0.190 ± 0.020
(4.826 ± 0.508)
A
0.500
MIN
(12.700)
0.018
Ty p
(0.457)
0.050
MAX
(1.270)
Uncontrolled
Lead Dia.
5° NOM
Seating Plane
L
123
0.015 ± 0.005
Typ
(0.381 ± 0.127)
Before Lead Finish
b
0.050 ± 0.005
(1.270 ± 0.127)
e1
0.100 ± 0.005
(2.540 ± 0.127)
e
C
H
0.050 ± 0.005
(1.270 ± 0.127)
E
0.140 ± 0.005
(3.556 ± 0.127)
10° NOM
1
2 3
0.090
R NOM
(2.286)
8-Lead Small Outline Package (LG, TG)
0.192 ± 0.005
(4.8895 ± 0.1143)
D
H
0.236 ± 0.008
(5.9944 ± 0.2032)
H1
E
0.154 ± 0.004
(3.9116 ± 0.1016)
0.193 ± 0.012
(4.9022 ± 0.3048)
h
7° (4 PLCS)
0.010 ± 0.002
C
(0.254 ± 0.0508)
0.061 ± 0.008
A
(1.5494 ± 0.2032)
45°
L1
0° - 8 °
e
B
A1
0.007 ± 0.003
(0.1778 ± 0.0762)
0.020 ± 0.009
(0.508 ± 0.2286)
0.050
TYP.
(1.270)
0.016 ± 0.002
(0.4064 ± 0.0508)
Note: Circle (e.g. B ) indicates JEDEC Reference.
L
0.035 ± 0.015
(0.889 ± 0.381)
Measurement Legend =
0.0275 ± 0.0025
(0.6985 ± 0.0635)
Dimensions in Inches
(Dimensions in Millimeters)
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LR12
Doc.# DSFP-LR12
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