## TL084MP: JFET-Input Quad Operational Amplifier The **TL084MP** belongs to the TL08x family of general-purpose operational amplifiers. It is distinguished by its high-speed JFET (Junction Field-Effect Transistor) input stage and its specific military/high-reliability temperature rating. --- ### 1. Key Technical Specifications The "MP" suffix typically denotes a specific package and military-grade temperature range. Below are the primary electronic characteristics: | Parameter | Typical Value | | :--- | :--- | | **Number of Channels** | 4 (Quad) | | **Input Type** | JFET | | **Supply Voltage Range** | $\pm5V$ to $\pm15V$ (Max $\pm18V$) | | **Input Bias Current** | 30 pA (extremely low) | | **Slew Rate** | 13 V/µs | | **Gain Bandwidth Product** | 3 MHz | | **Operating Temperature** | -55°C to 125°C | --- ### 2. Internal Electronic Features The TL084MP is designed with several internal stages that define its performance: * **JFET Input Stage:** Unlike bipolar op-amps, the use of JFETs at the input ensures very high input impedance ($10^{12} \Omega$). This prevents the circuit from loading the source signal. * **Internal Frequency Compensation:** It is internally compensated for unity gain stability, meaning it won't oscillate even when the output is fed directly back to the negative input. * **Output Short-Circuit Protection:** The device includes circuitry to prevent damage if the output is accidentally grounded or shorted. * **Low Harmonic Distortion:** It maintains high signal integrity, typically around 0.003%, making it suitable for high-fidelity audio applications. --- ### 3. Pinout Configuration The TL084MP is a 14-pin device. The four amplifiers share the power supply pins but operate independently. | Pin Number | Function | Pin Number | Function | | :--- | :--- | :--- | :--- | | 1 | Output 1 | 8 | Output 3 | | 2 | Inverting Input 1 | 9 | Inverting Input 3 | | 3 | Non-inverting Input 1 | 10 | Non-inverting Input 3 | | 4 | $V_{CC}+$ (Positive Supply) | 11 | $V_{CC}-$ (Negative Supply) | | 5 | Non-inverting Input 2 | 12 | Non-inverting Input 4 | | 6 | Inverting Input 2 | 13 | Inverting Input 4 | | 7 | Output 2 | 14 | Output 4 | --- ### 4. Common Applications Due to its high input impedance and wide temperature range, the TL084MP is used in: 1. **High-Impedance Buffers:** Connecting sensors with very low current output. 2. **Active Filters:** Designing low-pass, high-pass, and band-pass filters with minimal signal degradation. 3. **Audio Preamplifiers:** Used in mixers and equalizers due to low noise and high slew rate. 4. **Military/Aerospace Electronics:** Where components must survive extreme cold or heat. --- ### 5. Circuit Example: Basic Non-Inverting Amplifier ```python # Gain Formula: Vout = Vin * (1 + R2/R1) # Input (+) connects to Pin 3 # Feedback Resistor (R2) connects Pin 1 to Pin 2 # Gain Resistor (R1) connects Pin 2 to Ground ```