The LM339DR is a quad comparator IC, which is part of Texas Instruments' range of products. It features four independent Comparators in a single package. Below is a detailed explanation of the LM339DR pinout, pin functions, packaging information, and additional FAQ.
Package Type:
The LM339DR is typically available in a 14-pin Dual In-line Package (DIP) or Surface Mount (SOIC). Here, I’ll provide the SOIC-14 (Surface Mount) package pinout for clarity.
LM339DR Pinout and Functions:
Pin # Pin Name Pin Function Description 1 Output 1 The output of comparator 1. Open collector output, requiring an external pull-up resistor. 2 Inverting Input 1 Inverting input for comparator 1. This pin receives the reference voltage to compare with the non-inverting input. 3 Non-inverting Input 1 Non-inverting input for comparator 1. This pin receives the signal that will be compared with the reference input. 4 V- Negative voltage supply pin. Typically, it connects to ground (0V) in most applications. 5 Inverting Input 2 Inverting input for comparator 2. Similar to comparator 1's inverting input. 6 Non-inverting Input 2 Non-inverting input for comparator 2. Similar to comparator 1's non-inverting input. 7 Output 2 Output of comparator 2. Like output 1, it is an open-collector output requiring an external pull-up resistor. 8 V+ Positive voltage supply pin. Typically connects to a positive voltage rail (e.g., +5V). 9 Output 3 Output of comparator 3. Open collector output, similar to the other outputs requiring an external pull-up resistor. 10 Inverting Input 3 Inverting input for comparator 3. Similar to Comparators 1 and 2. 11 Non-inverting Input 3 Non-inverting input for comparator 3. Similar to comparators 1 and 2. 12 Output 4 Output of comparator 4. Open collector output, requiring external pull-up resistor like other outputs. 13 Inverting Input 4 Inverting input for comparator 4. Similar to other comparators' inverting inputs. 14 Non-inverting Input 4 Non-inverting input for comparator 4. Similar to other comparators' non-inverting inputs.Explanation of Pin Functions:
Comparators (1-4): The LM339DR consists of four independent comparators that compare two analog input voltages and output a high or low signal depending on the comparison.
Open Collector Output: Each comparator output is an open-collector configuration, meaning that the output is either low (0V) or floating. An external pull-up resistor is needed to pull the output to a higher voltage level when the output is not active (low).
Inverting and Non-inverting Inputs: Each comparator has two inputs, one inverting (−) and one non-inverting (+). The comparison between these two inputs determines whether the output will be active or inactive. If the non-inverting input has a higher voltage than the inverting input, the output will be pulled low.
Power Supply Pins (V+ and V-): The LM339DR operates with a dual power supply, where V+ connects to the positive supply voltage and V- connects to ground or the negative supply voltage.
FAQ for LM339DR:
Q1: What is the LM339DR? A1: The LM339DR is a quad comparator IC with four independent open-collector comparator circuits in a single package. It is commonly used for voltage comparison tasks in various applications such as sensors, alarms, and control systems.
Q2: How do I use the LM339DR in a circuit? A2: The LM339DR can be used in voltage comparison circuits. The non-inverting and inverting inputs are connected to the signal and reference voltages, while the output is connected to an external pull-up resistor.
Q3: What type of outputs does the LM339DR have? A3: The LM339DR has open-collector outputs, meaning the output can either be pulled low or be in a floating state. A pull-up resistor is required to bring the output to a high state when not actively driven low.
Q4: Can I use the LM339DR with a single supply voltage? A4: Yes, the LM339DR can be used with a single supply voltage, but it typically requires a supply voltage of V+ (e.g., +5V) and V- (typically ground). You can also use a dual supply if required by your design.
Q5: What voltage range does the LM339DR operate at? A5: The LM339DR operates with a supply voltage ranging from 2V to 36V for single supply operation, or ±1V to ±18V for dual supply operation.
Q6: What is the function of the pull-up resistor on the output pins? A6: The pull-up resistor ensures that the output voltage is pulled high (to V+) when the comparator output is not actively driven low. Without a pull-up resistor, the output would be floating and unpredictable.
Q7: Can I drive a load directly from the LM339DR output? A7: No, the LM339DR has an open-collector output, meaning it cannot drive a load directly. You need to use a pull-up resistor and potentially a transistor or other driver if driving high-current loads.
Q8: How accurate is the voltage comparison in the LM339DR? A8: The accuracy depends on the input voltage and the design of the circuit. The LM339DR offers low offset voltage, which helps improve accuracy in voltage comparison applications.
Q9: What is the typical response time of the LM339DR? A9: The response time of the LM339DR depends on the voltage difference between the inputs and the load. Typically, it can respond in tens of nanoseconds to microseconds.
Q10: How should I protect the inputs of the LM339DR? A10: The inputs of the LM339DR should be protected from over-voltage conditions that could exceed the supply voltage. Adding series resistors and clamping diodes can help protect the inputs.
Q11: Can the LM339DR be used for temperature sensing applications? A11: Yes, the LM339DR can be used for temperature sensing if you have a temperature sensor like a thermistor or thermocouple that provides a voltage signal, which can be compared with a reference voltage.
Q12: Can I use the LM339DR in a low-power design? A12: Yes, the LM339DR is suitable for low-power applications as it consumes very little current when idle.
Q13: What is the maximum current the LM339DR can sink at the output? A13: The LM339DR can sink up to 50mA at each output when the output is pulled low.
Q14: What type of resistor should I use for the pull-up resistor? A14: The value of the pull-up resistor typically ranges from 1kΩ to 10kΩ, depending on the desired output current and voltage.
Q15: Can the LM339DR be used for digital logic comparison? A15: Yes, the LM339DR is frequently used for digital logic comparison, where it compares two digital signals and outputs either high or low.
Q16: Does the LM339DR require an external oscillator for operation? A16: No, the LM339DR does not require an external oscillator. It operates based on the analog voltage comparison between its inputs.
Q17: What happens when the input voltage exceeds the supply voltage? A17: Exceeding the supply voltage on the input pins may damage the LM339DR. It is important to ensure that the input voltage is within the allowable range specified in the datasheet.
Q18: Can I use the LM339DR to compare AC signals? A18: Yes, you can use the LM339DR to compare AC signals, but the signal needs to be biased appropriately to fit within the comparator's input voltage range.
Q19: What is the benefit of using the LM339DR over other comparators? A19: The LM339DR has a low offset voltage, low power consumption, and is capable of working over a wide range of supply voltages, making it versatile for many applications.
Q20: Where can I use the LM339DR in practical applications? A20: The LM339DR can be used in various applications, including signal conditioning, voltage level detection, motor control circuits, and analog-to-digital conversion systems.
Summary
The LM339DR is a versatile, low-power quad comparator IC with open-collector outputs. It is widely used in voltage comparison applications, with each of its four comparators offering independent inputs and outputs. The device features excellent accuracy and flexibility, making it ideal for use in sensors, alarms, and control circuits. The pinout and functionality have been explained in detail, along with common FAQs to aid understanding of its operation.