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Application Report
SLVA696–April 2015
Abstract
AndrewLeverette
ABSTRACT
Traditionally engineers have used discrete active devices in order to boost the output current of an opamp.
ALM2402Q1 is able to eliminate these due to its own class AB output stage that can drive up to 400 mA.
In addition to its output drive capability, it has many protection features that are optimal for driving low
impedances, making it a robust device in industrial and automotive applications. This application note will
describe the features of the ALM2402Q1 and provide some suggested applications for which it may be
used.
Contents
1 Key Benefits.................................................................................................................. 2
2 Features....................................................................................................................... 2
2.1 Output Drive ......................................................................................................... 2
2.2 Stability............................................................................................................... 3
3 Power Budgeting and Thermal Properties................................................................................ 4
4 Applications................................................................................................................... 5
4.1 Tracking LDO........................................................................................................ 5
4.2 Servo (Analog) Motor Drive ....................................................................................... 7
4.3 Resolver Excitation ................................................................................................. 8
5 Conclusion.................................................................................................................... 9
List of Figures
1 Discrete Power Opamp Implementation.................................................................................. 2
2 Output High (VOH) vs. Temperature...................................................................................... 3
3 Output Low (VOL) vs. Temperature....................................................................................... 3
4 Heavy Load Gain ............................................................................................................ 3
5 Light Load Gain .............................................................................................................. 3
6 Heavy Load Phase .......................................................................................................... 4
7 Light Load Phase ............................................................................................................ 4
8 Tracking LDO Example ..................................................................................................... 5
9 PMOS (High Side) & NMOS (Low Side) Output Diode Forward Voltage ............................................ 6
10 ALM2402Q1 Used as a Brushed DC Motor Driver...................................................................... 7
11 ALM2402Q1 Used as a Servo Motor Driver ............................................................................. 8
12 Resolver Exciation........................................................................................................... 9
List of Tables
1 Motor Control Signal and Communication Direction .................................................................... 7
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SLVA696–April 2015 Designing with Dual Power Opamp, ALM2402Q1
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