LM2904DT Dual Operational Amplifier: Features, Package and Specifications
10 April 2024
Ⅱ. Electrical characteristic curves
Ⅴ. Supply voltage and current requirements of LM2904DT
Ⅶ. How to use LM2904DT in circuit design?
Ⅷ. How to apply LM2904DT in transducer amplifier?
The LM2904DT is a dual op-amp integrated circuit manufactured by ST that consists of two independent high-gain operational amplifiers with internal frequency compensation implemented. This circuit can be powered from a single supply over a wide voltage range and its low supply drain is independent of the magnitude of the supply voltage. The device is widely used in sensor amplifiers, DC gain blocks, and all traditional op amp circuits, making them easier to implement in single-supply systems. For example, these circuits can be powered directly from the standard 5V power supply commonly used in logic systems, eliminating the need for additional power supplies and easily providing the required electronic interface. In linear mode, the input common-mode voltage range includes ground and the output voltage can swing to ground, even from a single supply.
Alternative models:
• LM2904D
• LM358DT
• Large DC voltage gain: 100 dB
• Large output voltage swing 0 V to [(VCC +) -1.5 V]
• Low input offset current: 2 nA
• Low input bias current: 20 nA (temperature compensated)
• Input common-mode voltage range includes negative rail
• Frequency compensation implemented internally
• Differential input voltage range equal to the power supply voltage
• Wide bandwidth (unity gain): 1.1 MHz (temperature compensated)
• Very low supply current/amplifier, essentially independent of supply voltage
The following is the package diagram of LM2904 for reference:
The length of LM2904DT is 5 mm, the width is 4 mm, and the height reaches 1.65 mm. It is available in SOIC-8 package form and packaged in tape & reel (TR). SOIC package is small and reliable, so it can meet a wide range of application needs, especially suitable for chip designs with high requirements on sensitivity, complexity and speed. Since the core contact part of the package is made of metal, the temperature control performance of the IC is better, thus extending its service life. Since the SOIC circuit board has a small number of ports, the network connection method is relatively simple when interconnecting devices. In addition, SOIC packages built on standard PCB substrates also facilitate surface mounting of passive components.
To ensure that the power supply system can meet its operating requirements, the following lists some of the LM2904DT supply voltage and current requirements.
1. Supply voltage: Typical value is 3 V to 32 V. This is the range of supply voltage required by the LM2904DT. In the design, we should ensure that the supply voltage provided is within this range.
2. Supply current: Typical value is 1.5 mA to 2.8 mA (per circuit). This is the total supply current consumption of the LM2904DT during operation. This value is an important reference for design and selection of power supply capacity.
3. Output short-circuit current: Typical value is 30 mA to 50 mA, which is the maximum current that the LM2904DT can provide when the output is short-circuited. Care should be taken to avoid excessive loads that could lead to a short-circuit condition.
4. Quiescent current: Typical value is 0.8 mA to 1.6 mA (per circuit). This is the quiescent current consumption of the LM2904DT under normal operating conditions. This value may be an important consideration in some low power applications.
• Its manufacturer is STMicroelectronics.
• The device uses bipolar technology.
• LM2904DT has 2 channels.
• LM2904DT has a common mode rejection ratio of 100 dB.
• Its gain bandwidth product is 1.1 MHz.
• Its input bias current is 200nA.
• Its operating supply current is 1.2mA.
• Its slew rate is 600 mV/us.
• Its installation method is surface mount.
• Its power supply voltage is 3V to 30V.
• The op amp has a temperature range of -40 °C to 125 °C.
• LM2904DT comes in SOIC-8 package and tape & reel (TR) packaging.
• LM2904DT belongs to the category of operational amplifiers - op amps.
Listed below are some common uses of LM2904DT in circuits:
1. Filtering: LM2904DT can be combined with resistors, capacitors and other components to form various filters to extract or suppress specific frequency components in signals. By adjusting the values of resistors and capacitors, the frequency response characteristics of the filter can be customized to achieve different filtering effects such as low pass, high pass, band pass or band stop. A low-pass filter allows low-frequency signals to pass through and suppresses high-frequency signals; a high-pass filter allows high-frequency signals to pass through and suppresses low-frequency signals. Bandpass filters only allow signals within a specific frequency range to pass, while bandstop filters suppress signals within this range.
2. Voltage follower: LM2904DT can be used as a voltage follower, that is, the output voltage is basically the same as the input voltage, but has greater current output capability. As a voltage follower, LM2904DT plays the role of buffering and isolation in the circuit, allowing the output voltage to stably follow changes in the input voltage, while avoiding mutual influence between the front and rear circuits.
3. Signal conversion: LM2904DT can convert the input voltage signal into the corresponding current output through its internal operation amplification mechanism. At the same time, LM2904DT through its flexible circuit configuration and accurate amplification capabilities, can easily realize the current to voltage conversion, so that the current signal can be effectively collected, processed and analyzed.
4. Signal amplification: When weak input signals enter the LM2904DT, its internal operational amplification mechanism will respond quickly to amplify these tiny signals. By adjusting the gain setting of LM2904DT, we can precisely control the amplification of the signal, thus ensuring that the amplitude of the output signal meets the requirements of subsequent circuit processing or measurement.
5. Signal arithmetic: Through different external circuit connections, the LM2904DT can realize a variety of mathematical operations, such as summing, differencing, integrating, differentiating, and so on. This makes it widely used in analog signal processing, control systems and measuring instruments.
6. Comparator: When used as a comparator, the LM2904DT accurately compares the input signal with the reference voltage. When the input signal exceeds the reference voltage, the comparator will output a high level; while when the input signal is lower than the reference voltage, it will output a low level. This logic judgment function enables the LM2904DT to convert analog signals to digital signals, thus achieving an effective connection between analog and digital circuits.
7. Buffering and isolation: LM2904DT can be used as a buffer to effectively reduce the mutual influence between circuits by isolating the front and rear circuits. In complex circuits, various parts are often interrelated, and signal transmission and processing between each other may be interfered. The introduction of the buffer is like a barrier in the circuit, isolating the front and rear circuits, so that each part can work independently and stably.
First, we need to choose the appropriate power supply. Since the LM2904DT can be powered by a single power supply over a wide range of voltages, we need to select a power supply voltage that is suitable for the particular application. Next, we will design the input circuit. In this process, we connect the output of a transducer (e.g., a sensor) to one of the LM2904DT's op-amp inputs. Considering the output signal characteristics of the transducer, we may also need to design an appropriate filter circuit or impedance matching circuit. Subsequently, in order to achieve the desired gain, we need to feed the output signal back to the inverting input of the operational amplifier through an appropriate feedback resistor and feedback network. The LM2904DT has excellent high gain characteristics, so by adjusting the resistance of the feedback resistor, we can easily achieve the desired gain. In addition, depending on the actual need, we may also need to adjust the bias and bias current of the LM2904DT in order to further optimize the performance of the amplifier. After completing these steps, we will design the output circuit to connect the output of the LM2904DT to a suitable load or subsequent circuit. During this process, we may also need to design appropriate buffer or filter circuits to minimize distortion or noise in the output signal. Finally, after completing the circuit design, we need to conduct tests to verify the performance of the amplifier. Based on the test results, we may also need to adjust the circuit parameters to further optimize the amplifier's gain, noise, distortion, and other performance metrics.
Frequently Asked Questions
1. What is the working principle of amplifier?
The amplifier principle is to generate an output signal that is a replica of the input signal with an increased higher magnitude. Note: Amplifiers strengthen or boost the weak signal without changing any input or information. Negative feedback is used in amplifiers.
2. What are the common applications of LM2904DT?
LM2904DT is commonly used in audio amplifiers, voltage followers, signal conditioning circuits, and other low-frequency applications.
3. What are some features of LM2904DT?
Some features include low input offset voltage, low input bias current, high slew rate, and wide voltage supply range, making it suitable for various analog signal processing tasks.
