SLOS217I July   1998  – December 2024 THS3001

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Pin Configuration and Functions
  6. 5 Specifications
    1. 5.1 Absolute Maximum Ratings
    2. 5.2 ESD Ratings
    3. 5.3 Recommended Operating Conditions
    4. 5.4 Thermal Information
    5. 5.5 Electrical Characteristics
    6. 5.6 Typical Characteristics
  7. 6 Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagram
    3. 6.3 Device Functional Modes
  8. 7 Application and Implementation
    1. 7.1 Application Information
      1. 7.1.1 Recommended Feedback and Gain Resistor Values
      2. 7.1.2 Noise Calculations
      3. 7.1.3 Slew Rate
      4. 7.1.4 Offset Voltage
    2. 7.2 Typical Applications
      1. 7.2.1 General Configurations
      2. 7.2.2 Driving a Capacitive Load
    3. 7.3 Power Supply Recommendations
    4. 7.4 Layout
      1. 7.4.1 Layout Guidelines
        1. 7.4.1.1 PCB Design Considerations
        2. 7.4.1.2 Thermal Considerations
  9. 8 Device and Documentation Support
    1. 8.1 Device Support
      1. 8.1.1 Evaluation Board
    2. 8.2 Receiving Notification of Documentation Updates
    3. 8.3 Support Resources
    4. 8.4 Trademarks
    5. 8.5 Electrostatic Discharge Caution
    6. 8.6 Glossary
  10. 9 Revision History
  11. 10Mechanical, Packaging, and Orderable Information

7.1.1 Recommended Feedback and Gain Resistor Values

The THS3001 is fabricated using Texas Instruments 30V complementary bipolar process, HVBiCOM. This process provides the excellent isolation and extremely high slew rates that result in excellent distortion characteristics.

As with all current-feedback amplifiers, the bandwidth of the THS3001 is an inversely proportional function of the value of the feedback resistor (see Figures 26 to 34). Table 7-1 shows the recommended resistors for an optimized frequency response. Use these values as a starting point, and after optimized values are found, use a 1% tolerance resistors to maintain frequency response characteristics. For most applications, a feedback resistor value of 1kΩ is recommended, a good compromise between bandwidth and phase margin that yields a stable amplifier.

Table 7-1 Recommended Resistor Values for an Optimized Frequency Response
GAIN RF FOR VCC = ±15V RF FOR VCC = ±5V
1 1kΩ 1kΩ
2, –1 680Ω 750Ω
2 620Ω 620Ω
5 560Ω 620Ω

Consistent with current-feedback amplifiers, increasing the gain is best accomplished by changing the gain resistor, not the feedback resistor. The reason is because the bandwidth of the amplifier is dominated by the feedback resistor value and internal dominant-pole capacitor. The ability to control the amplifier gain independent of the bandwidth constitutes a major advantage of current-feedback amplifiers over conventional voltage-feedback amplifiers. Therefore, after a frequency response is found that is designed for a particular application, adjust the value of the gain resistor to increase or decrease the overall amplifier gain.

Finally, make sure to realize the effects of the feedback resistance on distortion. Increasing the resistance decreases the loop gain and increases the distortion. Knowing that decreasing load impedance increases total harmonic distortion (THD) is also important Typically, the third-order harmonic distortion increases more than the second-order harmonic distortion.