How to use the LM339 quad voltage comparator

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How to use the LM339 quad voltage comparator [Copy link]

The LM339 integrated circuit has four independent voltage comparators installed inside. The characteristics of this voltage comparator are: 1) small offset voltage, typical value is 2mV; 2) wide power supply voltage range, single power supply is 2-36V, dual power supply voltage is ±1V-±18V; 3) wide internal resistance limit for comparison signal source; 4) large common mode range, 0~(Ucc-1.5V)Vo; 5) large differential input voltage range, large enough to be equal to the power supply voltage; 6) output terminal potential can be flexibly and conveniently selected. The LM339 integrated circuit adopts C-14 package, and Figure 1 shows the appearance and pin arrangement diagram. Because LM339 is flexible and widely used, major IC manufacturers and companies in the world have launched their own four comparators, such as IR2339, ANI339, SF339, etc. Their parameters are basically the same and can be used interchangeably. Figure 1 LM339 is similar to an operational amplifier with non-adjustable gain. Each comparator has two input terminals and one output terminal. One of the two input terminals is called the in-phase input terminal, represented by "+", and the other is called the inverting input terminal, represented by "-". When used to compare two voltages, a fixed voltage is added to any input terminal as a reference voltage (also called a threshold level, which can be selected at any point in the LM339 input common mode range), and a signal voltage to be compared is added to the other terminal. When the voltage at the "+" terminal is higher than that at the "-" terminal, the output tube is cut off, which is equivalent to an open circuit at the output terminal. When the voltage at the "-" terminal is higher than that at the "+" terminal, the output tube is saturated, which is equivalent to a low potential at the output terminal. If the voltage difference between the two input terminals is greater than 10mV, it can ensure that the output can be reliably converted from one state to another. Therefore, it is ideal to use LM339 in occasions such as weak signal detection. The output terminal of LM339 is equivalent to a crystal triode without a collector resistor. When in use, a resistor (called a pull-up resistor, select 3-15K) is generally connected from the output terminal to the positive power supply. Selecting pull-up resistors of different resistance values will affect the value of the high potential of the output terminal. Because when the output transistor is cut off, its collector voltage basically depends on the value of the pull-up resistor and the load. In addition, the output terminals of each comparator can be connected together for use.

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I don't really understand common mode and differential mode input voltages. If my chip is powered by 5V, can my comparator input be greater than 5V for comparison? ? ?