LR12 Datasheet, PDF (1/9 Pages) Supertex, Inc – High Input Voltage Adjustable 3-Terminal Linear Regulator

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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
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
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 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.
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.
The device is available in TO-92, SO-8, and TO-252 (D-PAK)
packages.
LR12 Typical Application
*
V_IN
13.2V to
100V
C1
V
V
IN
OUT
ADJ
LR12
R2
V_OUT
1.2V to 88V
R1
C2
R_LOAD
*Required for conditions where V_IN is less than V_OUT.
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