LM3411-L Datasheet, PDF (1/31 Pages) Texas Instruments – Precision Secondary Regulator and Driver

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LM3411-L Precision Secondary Regulator and Driver
LM3411-L
SNVSAX5 – JUNE 2017
1 Features
•1 Fixed Voltages of 3.3 V and 5 V With Initial
Tolerance of ±1% for Standard Grade and ±0.5%
for A Grade
• Custom Voltages Available (3 V to 17 V)
• Wide Output Current Range (20 μA to 15 mA)
• Low Temperature Coefficient
• Available in 5-Pin SOT-23 Surface-Mount
Package (Tape and Reel)
2 Applications
• Secondary Controller for Isolated DC-DC PWM
Switching Regulators Systems
• Use With LDO Regulator for High-Precision,
Fixed-Output Regulators
• Precision Monitoring Applications
• Use With Many Types of Regulators to Increase
Precision and Improve Performance
3 Description
The LM3411-L is a low-power fixed-voltage (3.3 V or
5 V) precision shunt regulator designed specifically
for driving an optoisolator to provide feedback
isolation in a switching regulator.
The LM3411-L circuitry includes an internally
compensated operational amplifier, a bandgap
reference, NPN output transistor, and voltage setting
resistors.
A trimmed precision bandgap reference with
temperature drift curvature correction provides a
ensured 1% precision over the operating temperature
range (A grade version). The inverting input of the
amplifier is externally accessible for loop frequency
compensation when used as part of a larger servo
system. The output is an open-emitter NPN transistor
capable of driving up to 15 mA of load current.
Because of its small die size, the LM3411-L has been
made available in the subminiature 5-pin SOT-23
surface-mount package. This package is ideal for use
in space-critical applications.
Although its main application is to provide a precision
output voltage (no trimming required) and maintain
very good regulation in isolated DC-DC converters, it
can also be used with other types of voltage
regulators or power semiconductors to provide a
precision output voltage without precision resistors or
trimming.
Typical Application Schematic
V+
Isolation Barrier
Simplified Pulse
Width Modulator
(PWM)
(Primary Side)
Feedback
Output
+
OUT
(+) IN
LM3411-L
COMP.
CC
+
Regulated
Output Voltage
-
Opto-isolator
( - ) GND
Copyright © 2017, Texas Instruments Incorporated
Device Information⁽¹⁾
PART NUMBER
PACKAGE
BODY SIZE (NOM)
LM3411-L
SOT-23 (5)
2.90 mm × 1.60 mm
(1) For all available packages, see the orderable addendum at
the end of the data sheet.
LM3411-L Functional Diagram
(+) IN
OUT
1.23 V ⁺
+
31 k
COMP.
±
Rf
( - ) GND _{Rf, 52 k for 3.3 V}
94 k for 5 V
Copyright © 2017, Texas Instruments Incorporated
1
An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,
intellectual property matters and other important disclaimers. PRODUCTION DATA.