TL082 JFET-Input Dual Operational Amplifier: Datasheet Breakdown and Design Guide

Key Takeaway

• Positioning: The TL082 is a high-speed, general-purpose dual JFET-input operational amplifier optimized for high-impedance signal conditioning where low input bias current is critical.

• Key Spec Highlight: Features a high slew rate of 13 V/µs and extremely low input bias current (30 pA typical), making it superior to standard bipolar op-amps like the LM358 for high-speed audio and sensor applications.

• Supply Chain Status:  High Counterfeit Risk. Due to market popularity, unauthorized sources frequently rebrand superior low-cost bipolar chips (like LM358) as TL082s. Always procure from authorized distributors.

TL082 product photo

1. Technical Architecture and Core Advantages

The TL082 integrates two independent operational amplifiers on a single monolithic chip. Its JFET-input architecture provides specific advantages over standard bipolar inputs, primarily in input impedance and slew rate performance.

1.1 Signal Processing Core (JFET Input Stage)

The TL082 utilizes high-voltage JFET transistors at the input stage. Use this architecture when your design requires: 

High Input Impedance: Minimizes loading effects on sensor sources. 

Low Input Bias Current: Typical 30 pA (at 25°C), significantly reducing error in high-impedance feedback networks. 

High Slew Rate: The 13 V/µs capability allows the device to track fast-changing signals without distortion, a common limitation in older general-purpose op-amps.

1.2 Output Stage & Protection

The output stage is designed for robust operation in industrial environments. 

Short-Circuit Protection: Built-in output short-circuit protection prevents damage during temporary fault conditions. 

Latch-Up Free: The internal design prevents latch-up, provided the inputs remain within the common-mode range. 

Internal Frequency Compensation: Eliminates the need for external compensation components for unity-gain stability.

TL082 functional block diagram internal architecture

2. Naming / Variant Map and Selection Guide

The TL082 series uses specific suffixes to denote package types and temperature grades.

2.1 Part Number Decoding

Follow this logic to select the correct part for your bill of materials (BOM):

• TL082C: Commercial standard grade.

• TL082I: Industrial temperature grade.

• Dt / PT: Suffixes indicating surface mount package styles (SO-8 vs TSSOP-8).

• P: Suffix typically indicating Through-Hole (DIP-8).

2.2 Core Variant Comparison

3. Key Specifications Explained

Engineer's Note: Values below are typical at 25°C. The TL082 is NOT a rail-to-rail device. Designs must account for headroom.

3.1 Power & Operating Conditions

The TL082 requires a dual supply for optimal symmetrical performance but can operate on a single supply if biased correctly. 

Supply Voltage (Vcc): Operating range is ±6V to ±18V. 

Design Constraint: This device requires significant voltage headroom. It is not suitable for 3.3V or 5V logic-level single-supply systems without a split-rail architecture.

3.2 Performance & Efficiency

• Slew Rate: 13 V/µs (Typical @ Vcc = ±15V). This defines the maximum rate of change of the output voltage.

• Gain Bandwidth Product (GBP): 4 MHz. Sufficient for audio pre-amplifiers and medium-speed active filters.

• Input Bias Current: 30 pA. Critical for "Sample and Hold" circuits where leakage current causes voltage droop.

slew rate vs frequency graph

4. Design Notes and Common Integration Issues

4.1 PCB Layout Guidelines

To preserve the low bias current and high slew rate performance: 

Guard Rings: For high-impedance designs, place guard rings around the inverting input pins driven by the input voltage to minimize leakage currents. 

Power Rails: Place 0.1µF ceramic decoupling capacitors as close as possible to the VCC+ and VCC- pins to suppress high-frequency noise. 

Trace Separation: Keep analog inputs away from high-speed digital switching traces to prevent capacitive coupling of noise.

TL082 pinout diagram and footprint

4.2 Debugging Common Faults (Pain Points)

Problem 1: Phase Reversal

Symptom: The output suddenly flips polarity or latches to the opposite rail. 

Cause: The input common-mode voltage range is exceeded, particularly near the negative supply rail. 

Fix: Ensure input signals remain within the specified common-mode range. Leave at least a 3V headroom from the negative rail (e.g., if Vee is -15V, inputs should not go below -12V).

Problem 2: Counterfeit Components

Symptom: High noise, slow slew rate, or high input bias current closer to an LM358. 

Cause: Unscrupulous vendors re-labeling cheaper bipolar op-amps as JFET TL082s. 

Fix: Strictly purchase from authorized Tier-1 distributors (Mouser, DigiKey) to avoid "fake" silicon.

Problem 3: Clipping / Signal Distortion on Low Voltage

Symptom: Output signal is clipped even though it is within supply rails. 

Cause: The TL082 is not rail-to-rail. 

Fix: Increase supply voltage or migrate to a modern rail-to-rail alternative like the TS912 if strictly low-voltage operation is required.

5. Typical Applications

5.1 System Integration Analysis: Audio Pre-Amplifier

The TL082 is an industry standard for audio pre-amplifiers due to its 13 V/µs slew rate and JFET inputs. 

Why it works: The high input impedance does not load the audio source (e.g., guitar pickup or microphone), maintaining signal fidelity. The high slew rate ensures that high-frequency transients are amplified without "slewing" distortion. 

Implementation Note: Use a dual supply (e.g., ±12V) to maximize dynamic range and avoid the complexity of virtual grounds required in single-supply designs.

TL082 typical application circuit schematic

6. Competitors and Alternatives

When selecting a manufacturing partner or looking for upgrades:

• Vs. Texas Instruments TL082: Direct competitor. The specs are nearly identical as this is a standard industry part number. Selection often depends on stock availability and pricing.

• Vs. Analog Devices AD712: A precision upgrade. Offers tighter offset voltage but typically at a higher cost.

• Vs. Microchip MCP602: A CMOS alternative. Better for low-voltage, rail-to-rail applications where the high-voltage requirement of the TL082 is a hindrance.

• Migration Path: For 5V systems, consider migrating to Maxim Integrated MAX44251 or MCP602 for true rail-to-rail performance.

7. FAQ

• Q: What is the absolute maximum supply voltage for the TL082?    

  The TL082 typically supports dual supplies up to ±18V; always verify thermal dissipation limits in the datasheet.

• Q: Does the TL082 support rail-to-rail output?    

  No, the TL082 requires headroom regarding both the positive and negative power rails; output swing is typically Vcc - 1.5V to Vee + 1.5V.

• Q: Why does my TL082 output invert when the input goes low?  

   This is known as phase reversal, occurring when the input voltage drops below the allowed common-mode range (close to Vee).

• Q: Can I replace an LM358 with a TL082 directly?    

  Not always; while the pinout is often compatible, the TL082 requires a dual supply or specific biasing and does not support ground-sensing inputs like the LM358.

• Q: What is the main naming difference between TL082CP and TL082CD?    

  TL082CP is the DIP-8 (Through-Hole) package, while TL082CD is the SO-8 (Surface Mount) package.

8. Resources and Downloads

• Datasheet: TL082-1852339 Datasheet (PDF)

• Dev Tools: Breadboard (for DIP-8 variant), Audio DIY Kits.