What is the voltage of each pin of the LM339N

Do you want to test the LM339?Please ** a copy of the LM339 data, and then measure the voltage of each pin against the data. There are 4 voltage comparators inside, and when the power supply voltage is normal, the voltage of the non-inverting input of the comparator is greater than that of the inverting input voltage, and the output level is high.

Conversely, if the voltage of the non-inverting input is less than that of the inverting input, the output is low, and the test method is the same for the 4 comparators.

Key features:

1.The offset voltage is small, typically 2mV

2.The power supply voltage range is wide, the single power supply is 2--36V, and the dual power supply voltage is plus or minus 1V-plus or minus 18V

3.The internal resistance of the comparison signal source is limited widely.

4.The common mode range is relatively large.

5.The differential input voltage range is large enough to be equal to the supply voltage.

6.The output potential can be selected flexibly and conveniently.

Performance parameters. Dual in-line 14-pin package.

Number of channels: 4 channels

Output Type: Open Collector

Compensation voltage (max): 5 mV

Input bias current (max): 250 na

Supply voltage (max): 36 V

Supply voltage (min): 18 V

Supply current (max): 2 mA

Maximum operating temperature: 70 C

Minimum operating temperature: 0 C

Power consumption = 265mW

Pin No. Pin Function Operating Voltage (V) On-Circuit Resistance Value (K) 1 Voltage Sampling Output 4

2 Voltage sampling output 0

3 Power input 5 4

4 Voltage sampling inverting input 4

5. Voltage sampling in-phase input.

6 Voltage sampling inverting input 4

7. Voltage sampling non-inverting input.

8 Voltage sampling inverting input 4

9. Voltage sampling inverting input.

10 Voltage sampling inverting input 10

11 Voltage sampling non-inverting input.

12 0 0

13 Voltage sampling output 4

14 Voltage sampling output 4

The LM339 is similar to an operational amplifier with non-adjustable gain. Each comparator has two inputs and one output. One of the two inputs is called a non-inverting input, denoted by a "+", and the other is called an inverting input, denoted by a "-".

When comparing two voltages, add a fixed voltage to the reference voltage at any input (also known as a threshold level, which can be selected at any point in the LM339 input common-mode range) and add a signal voltage at the other input to end the comparison.

When the voltage at the "+" terminal is higher than the "-terminal", the output tube closes, which is equivalent to an open circuit at the output. When the voltage at the "-terminal" is higher than the "+" terminal, the output tube is saturated, which is equivalent to the output terminal being connected to a low potential. The voltage difference between the two input terminals is greater than 10mV, ensuring that the output can be reliably switched from one state to another.

Therefore, it is desirable to use the LM339 for weak signal detection, etc.

The output of the LM339 is equivalent to a transistor without collector resistance. In use, the output must be connected to a positive resistor (called a pull-up resistor, 3-15k). Choosing a pull-up resistor with a different value affects the high potential value at the output.

Because when the output transistor is turned off, its collector voltage basically depends on the value of the pull-up resistance and the load. In addition, the outputs of the comparator are allowed to be connected together.

Measurement method of voltage of each pin of LM339 chip:

1. First of all, it is necessary to find the reference point (ground terminal) of the chip and the negative pole of the power supply. As shown in the figure below, pin 12 is the ground end.

2. Take the grounding terminal as the reference point, use the DC 20 volt file of the multimeter, the black pen to the ground, and the red pen to measure the power supply voltage of the chip respectively, and then measure the voltage value of the input and output pins of each group of voltage comparators, and record the voltage parameters one by one.

3. LM339 is a chip with 4 sets of independent voltage comparators, the specific voltage value can refer to the LM339 data parameters, and the data measured by different peripheral circuits are not the same.

If it is a single power supply, the black watch pen is grounded, the +- power supply is also the black watch pen ground, but the measured output is sometimes negative, connected to the pull-up resistor, the output is positive and negative, and the single power supply is zero and high.

The 12 feet are the power negative, which is often referred to as the ground.

The LM339 is an open-collector output, and its pull-down output current is typically 16mA, which is usually not enough to drive a relay (it may be possible to drive a reed relay), but a triode current amplification circuit can be added to drive the relay. If you use a common emitter circuit to amplify the current, the two inputs of the LM339 should be interchanged. As shown in the figure below

The output current of LM339 is 15mA, because the output of LM339 is an open collector, so the output current is a sink current, that is, the current flows inward. Drive the relay, connect the pole of the relay coil to the output of LM339, and connect the other pole of the relay coil to the power supply. I choose a compact relay with a voltage of 5V, 12V, and a relay with a coil current of up to about 10mA.

There are four sets of voltage comparators inside the LM339, and their own voltage can be designed and selected from +2V to +36V, and it is not a problem to drive a relay.

The LM339 manifold is equipped with four independent voltage comparators inside, which are characterized by:

1) The offset voltage is small, the typical value is 2mV;

2) Wide range of power supply voltage, single power supply is 2-36V, dual power supply voltage is 1V-18V;

3) The internal resistance limit of the comparison signal source is wide;

4) The common mode range is very large, which is 0 (;

5) The differential input voltage range is large, which can be equal to the power supply voltage;

6) The output potential can be selected flexibly and conveniently.

The LM339 manifold is packaged in a C-14 package, and Figure 1 shows the appearance and pin arrangement. Due to the flexible use and wide application of LM339, the world's major IC manufacturers and companies have launched their own four comparators, such as IR2339, ANI339, SF339, etc., their parameters are basically the same, and they can be used interchangeably.

The LM339 is similar to an operational amplifier with non-adjustable gain. Each comparator has two inputs and one output. One of the two inputs is called the inverting input, denoted by a "+", and the other is called an inverting input, denoted by a "-".

When used to compare two voltages, add a fixed voltage to either input as a reference voltage (also known as a threshold level, which selects any point in the LM339 input common-mode range) and a signal voltage to be compared at the other end. When the voltage of the "+" terminal is higher than that of 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 the "+" terminal, the output tube is saturated, which is equivalent to the output termination with a low potential.

A voltage difference of more than 10mV between the two inputs ensures that the output can be reliably converted from one state to another, so the LM339 is ideal for weak signal detection. The output end of LM339 is equivalent to a crystal transistor without a collector resistor, and a resistor (called pull-up resistor, 3-15K) must be connected to the positive power supply from the output terminal to the positive power supply when in use. Choosing a pull-up resistor with different resistance values will affect the value of the high potential at the output.

Because when the output transistor is cut off, its collector voltage basically depends on the value of the pull-up resistance and the load. In addition, the outputs of each comparator can be connected together.

Single-limit comparator circuit.

lm339

Pin 5, Pin 7, Pin 8, Pin 10 are the "+" of the op amp circuit

Pin 4, Pin 6, Pin 9, Pin 11 are the "-" of the op amp circuit

Pin 2, Pin 1, Pin 14, Pin 13 is the "output" of the op amp circuit, also called outPin 3 is the power supply (power supply positive).

Pin 12 is the ground wire (power negative).

--This chip consists of four sets of circuits called op amps.

5, 4, 2 feet in a group.

7, 6, 1 foot in a group.

A group of 8, 9, 14 feet.

10, 11, 13 feet in a group.

--When comparing the two sets of voltages, connect the two sets of voltages to the "+" and "-" pins of any one of the op amps.

When the voltage on the "than" - "pin" is higher, the "output" pin will be high voltage. (Compare circuit electricity is usually 3 pin supply voltage).

When the voltage is higher than the voltage on the +" pin, the output pin will be low. (Compare the circuit electricity will usually be 12 pins without voltage).

Do you see it?

The upper limit of the working power supply voltage of LM339 is 36V, and 24V is impossible to damage.

The pull-up resistor in parallel with the relay coil is not necessary and can be removed.

The drive relay should be connected to the bleed diode in parallel at the relay coil, otherwise a high induced electromotive force will be generated to break down the components on the circuit board at the moment the relay is disconnected. See the image below

Dual in-line 14-pin package.

Number of channels: 4 channels

Output Type: Open Collector

Compensation voltage (max): 5 mV

Input bias current (max): 250 na

Supply voltage (max): 36 V

Supply voltage (min): 18 V

Supply current (max): 2 mA

Maximum operating temperature: 70 C

Minimum operating temperature: 0 C

Power consumption = 265mW

Pin No. Pin Function Operating Voltage (V) On-Circuit Resistance Value (K) 1 Voltage Sampling Output 4

2 Voltage sampling output 0

3 Power input 5 4

4 Voltage sampling inverting input 4

5. Voltage sampling in-phase input.

6 Voltage sampling inverting input 4

7. Voltage sampling non-inverting input.

8 Voltage sampling inverting input 4

9. Voltage sampling inverting input.

10 Voltage sampling inverting input 10

11 Voltage sampling non-inverting input.

12 0 0

13 Voltage sampling output 4

14 Voltage sampling output 4