TL084CN

Description

The TL084CN is the “Quad” version of the TL081. It houses four independent, high-speed, JFET-input operational amplifiers in a single 14-pin package. It is essentially the industry-standard choice when you need the high-performance characteristics of the TL081 series but want to save board space by using a single chip for multiple signal stages.

Key Specifications

• Number of Op-Amps: 4 (Quad)

• Input Stage: JFET (Very high input impedance)

• Slew Rate: 13 V/µs (Fast response)

• Input Bias Current: 30 pA (Very low)

• Supply Voltage: Up to ±18V

• Package Type: DIP-14 (Plastic package)

Pinout Configuration (DIP-14)

The TL084CN uses a standard quad-op-amp pinout.

1. Output 1

2. Inverting Input 1

    

3. Non-Inverting Input 1

    

4. VCC+

    

5. Non-Inverting Input 2

    

6. Inverting Input 2

    

7. Output 2

8. Output 3

9. Inverting Input 3

10. Non-Inverting Input 3

11. VCC-

12. Non-Inverting Input 4

13. Inverting Input 4

14. Output 4

Why Choose the TL084CN?

If you have a design that requires multiple filtering or amplification stages—like a stereo audio equalizer or a multi-channel sensor array—the TL084CN is significantly more efficient than using four individual TL081s.

• Note: Unlike the TL081, the quad TL084CN does not have dedicated Offset Null pins. If your application requires precise zero-offset calibration, you must either add a trim circuit externally or choose the single TL081 for those specific stages.

Common Applications

• Multi-Stage Active Filters: Because it has four amps, you can easily build a 4th-order filter (like a Butterworth or Sallen-Key) using just one chip.

• Audio Mixing Consoles: Perfect for buffering and summing multiple audio channels.

• Instrumentation Amplifiers: Used in designs requiring high input impedance to avoid loading down sensitive sensors.

• Precision Rectifiers: Using multiple stages to accurately convert AC to DC for measurement.

Usage Best Practices

• Power Supply: Like the TL081, this is designed for dual-polarity supplies. If you are using it in a single-supply circuit, ensure you provide a “virtual ground” bias (usually at $V_{CC}/2$) to the non-inverting inputs.

• Decoupling: With four high-speed amplifiers inside one package, the risk of supply-line noise is higher. Place a $0.1\mu\text{F}$ ceramic capacitor (and often a larger $10\mu\text{F}$ electrolytic capacitor) as close as possible to the power pins (4 and 11) to maintain stability.

• Thermal Management: While not a power IC, driving four heavy loads simultaneously can increase internal temperatures. Ensure adequate airflow if you are operating at the higher end of the voltage/current limits.