LR12
LR12
High Input Voltage
Adjustable 3-Terminal Linear Regulator
Features
❏
❏
❏
❏
❏
❏
❏
❏
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
General Description
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 R
1
and R
2
as shown in the typical application
circuits. The LR12 regulates the voltage difference between V
OUT
and ADJ pins to a nominal value of 1.20V. The 1.20V is amplified
by the external resistor ratio R
1
and R
2
. An internal constant bias
current of typically 10µA is connected to the ADJ pin. This
increases V
OUT
by a constant voltage of 10µA times R
2
.
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 V
OUT
of the LR12.
To maintain stability, a bypass capacitor of 100nF or larger and a
minimum DC output current of 500µA are required.
The device is available in TO-92, SO-8, and TO-252 (D-PAK)
packages.
Applications
❏
❏
❏
❏
❏
❏
❏
❏
❏
DC/DC SMPS startup circuits
Adjustable high voltage constant current sources
Industrial Controls
Motor Controls
Battery Powered Systems
Power Supplies
Telecom Applications
LED Drivers
Automotive Applications
LR12 Typical Application
*
V
OUT
1.2V to 88V
V
IN
13.2V to
100V
C1
V
IN
V
ADJ
OUT
LR12
R1
C2
R
LOAD
R2
*Required for conditions where V
IN
is less than V
OUT
.
A081605
A081605
1