The "LM2902DR" refers to a specific integrated circuit (IC) made by Texas Instruments. It is a part of the LM2900 series of operational amplifiers (op-amps). The "DR" in the part number refers to the specific package type used, which is an "SOIC-8" package.
Pinout Specifications and Circuit Principle Instructions for LM2902DR (SOIC-8 Package)
The LM2902DR is a quad operational amplifier. This means that the IC contains four independent op-amps inside the same package. Below is the pinout and detailed description of each pin function in the SOIC-8 package.
Pin Configuration (SOIC-8 Package)Pin 1 (Non-Inverting Input of Op-Amp 1): The non-inverting input for the first op-amp. Signals applied to this pin are amplified in the positive direction by the corresponding op-amp.
Pin 2 (Inverting Input of Op-Amp 1): The inverting input for the first op-amp. The signal applied here will result in an amplified output that is inverted (opposite phase).
Pin 3 (Output of Op-Amp 1): This is the output of the first operational amplifier in the LM2902. The amplified signal is taken from this pin. The output is typically used in feedback loops to stabilize the circuit.
Pin 4 (Negative Supply Voltage, V-): This is the negative supply voltage pin. For the LM2902 to function, this pin must be connected to the negative side of the power supply. It is typically used in dual-supply configurations.
Pin 5 (Non-Inverting Input of Op-Amp 2): The non-inverting input for the second op-amp inside the IC. It is where the input signal is applied to generate a positive output voltage.
Pin 6 (Inverting Input of Op-Amp 2): The inverting input for the second op-amp. The signal applied to this pin results in an output that is phase-inverted.
Pin 7 (Output of Op-Amp 2): The output of the second operational amplifier. The amplified signal is taken from this pin.
Pin 8 (Positive Supply Voltage, V+): This is the positive supply voltage pin. The LM2902 requires a positive voltage for operation, which is connected to this pin.
Pin Function and Usage in Detail
Pin Number Pin Name Function Description 1 Non-Inverting Input of Op-Amp 1 Non-inverting input of the first op-amp. A positive voltage signal applied here will be amplified positively. 2 Inverting Input of Op-Amp 1 Inverting input of the first op-amp. A signal applied here will cause the output to be inverted. 3 Output of Op-Amp 1 Output of the first operational amplifier. The signal outputted here is the result of the amplification process. 4 Negative Supply Voltage (V-) Connects to the negative supply voltage. Typically used in a dual-supply configuration. 5 Non-Inverting Input of Op-Amp 2 Non-inverting input of the second op-amp. A positive signal applied to this pin is amplified and outputted in a positive phase. 6 Inverting Input of Op-Amp 2 Inverting input of the second op-amp. Signal here leads to an output that is the inverse of the input signal. 7 Output of Op-Amp 2 Output of the second operational amplifier, where the amplified signal is available for use. 8 Positive Supply Voltage (V+) Connects to the positive supply voltage. This is necessary for the operational amplifiers to function.Frequently Asked Questions (FAQ)
Q1: What is the LM2902DR used for? A1: The LM2902DR is used as a quad operational amplifier in various applications, including signal amplification, filtering, and instrumentation circuits.
Q2: What type of package does the LM2902DR come in? A2: The LM2902DR comes in the SOIC-8 package, which has 8 pins.
Q3: How do I connect the LM2902DR in my circuit? A3: Connect the negative supply voltage to pin 4 and the positive supply voltage to pin 8. Each op-amp has a non-inverting input (pin 1, 5), an inverting input (pin 2, 6), and an output (pin 3, 7).
Q4: Can the LM2902DR be used in single-supply circuits? A4: Yes, the LM2902DR can operate in single-supply configurations, where the negative supply pin (pin 4) is grounded.
Q5: What is the voltage range for the LM2902DR? A5: The LM2902DR can operate with supply voltages ranging from ±3V to ±32V, or a single supply of 5V to 32V.
Q6: How much current does the LM2902DR consume? A6: The typical supply current for the LM2902DR is about 1 mA per op-amp, totaling around 4 mA for all four op-amps.
Q7: Can the LM2902DR output both positive and negative voltages? A7: Yes, the LM2902DR can output both positive and negative voltages depending on the supply configuration and input signal.
Q8: What is the typical response time of the LM2902DR? A8: The LM2902DR has a typical slew rate of 0.3 V/μs, which determines how quickly it can change its output voltage in response to input changes.
Q9: Is the LM2902DR suitable for high-frequency applications? A9: The LM2902DR is more suitable for low-frequency applications, with a typical gain-bandwidth product of 1 MHz.
Q10: What is the input impedance of the LM2902DR? A10: The input impedance of the LM2902DR is typically 2 MΩ, which allows it to interface with high-impedance sources.
Q11: How stable is the LM2902DR in terms of temperature? A11: The LM2902DR operates within a wide temperature range of -40°C to +85°C, providing stability in a variety of environments.
Q12: Can the LM2902DR be used in feedback loops? A12: Yes, the LM2902DR is commonly used in feedback loops in amplifying circuits to control gain and stability.
Q13: How do I use the LM2902DR in an inverting amplifier configuration? A13: To use the LM2902DR in an inverting amplifier configuration, connect the input signal to the inverting input (pin 2 or 6), and use feedback from the output (pin 3 or 7) to the inverting input.
Q14: How do I use the LM2902DR in a non-inverting amplifier configuration? A14: For a non-inverting amplifier, connect the input signal to the non-inverting input (pin 1 or 5), and connect feedback from the output (pin 3 or 7) to the inverting input (pin 2 or 6).
Q15: What is the common-mode rejection ratio (CMRR) of the LM2902DR? A15: The typical CMRR for the LM2902DR is 80 dB, indicating its ability to reject common-mode signals effectively.
Q16: What are the output voltage swing limits of the LM2902DR? A16: The output voltage swing of the LM2902DR is typically within the supply rails, meaning it can swing close to V+ and V- but not necessarily all the way to the rails.
Q17: What is the power dissipation of the LM2902DR? A17: The power dissipation of the LM2902DR depends on the supply voltage and the load, but it is typically around 1 mW per op-amp.
Q18: How should I decouple the power supply when using the LM2902DR? A18: It is recommended to use decoupling capacitor s (typically 0.1 μF) between the supply pins (V+ and V-) and ground to reduce noise and improve stability.
Q19: Can I use the LM2902DR in audio applications? A19: The LM2902DR can be used in audio applications, but it is not ideal for high-fidelity audio due to its limited frequency response and slew rate.
Q20: What is the output drive capability of the LM2902DR? A20: The LM2902DR can drive a load of up to 10 kΩ with a reasonable output voltage swing, making it suitable for many general-purpose applications.
The LM2902DR is a versatile and reliable operational amplifier that can be used in a wide range of electronic applications, from basic amplification to more complex feedback and filtering circuits.
