SBOS875C August   2017  – February 2023 THS3491

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Device Comparison Table
  6. 6 Pin Configuration and Functions
  7. 7 Bare Die Information
  8. 8 Specifications
    1. 8.1 Absolute Maximum Ratings
    2. 8.2 ESD Ratings
    3. 8.3 Recommended Operating Conditions
    4. 8.4 Thermal Information
    5. 8.5 Electrical Characteristics: VS = ±15 V
    6. 8.6 Electrical Characteristics: VS = ±7.5 V
    7. 8.7 Typical Characteristics: ±15 V
    8. 8.8 Typical Characteristics: ±7.5 V
  9. 9 Detailed Description
    1. 9.1 Overview
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
      1. 9.3.1 Power-Down (PD) Pin
      2. 9.3.2 Power-Down Reference (REF) Pin
      3. 9.3.3 Internal Junction Temperature Sense (TJ_SENSE) Pin
    4. 9.4 Device Functional Modes
      1. 9.4.1 Wideband Noninverting Operation
      2. 9.4.2 Wideband, Inverting Operation
      3. 9.4.3 Single-Supply Operation
      4. 9.4.4 Maximum Recommended Output Voltage
  10. 10Application and Implementation
    1. 10.1 Application Information
      1. 10.1.1 Driving Capacitive Loads
      2. 10.1.2 Video Distribution
    2. 10.2 Typical Application
      1. 10.2.1 Design Requirements
      2. 10.2.2 Detailed Design Procedure
      3. 10.2.3 Application Curves
    3. 10.3 Power Supply Recommendations
    4. 10.4 Layout
      1. 10.4.1 Layout Guidelines
        1. 10.4.1.1 PowerPAD™ Integrated Circuit Package Design Considerations (DDA Package Only)
          1. 10.4.1.1.1 PowerPAD™ Integrated Circuit Package Layout Considerations
          2. 10.4.1.1.2 Power Dissipation and Thermal Considerations
      2. 10.4.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Documentation Support
      1. 11.1.1 Related Documentation
    2. 11.2 Receiving Notification of Documentation Updates
    3. 11.3 Support Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

9.4.1 Wideband Noninverting Operation

The THS3491 is a 900-MHz current-feedback operational amplifier that is designed to operate from a power supply of ±7 V to ±16 V.

#SLOS420FIG3931 shows the THS3491 in a noninverting gain configuration of 5 V/V which is used to generate the majority of the performance curves. Most of the curves are characterized using signal sources with a 50-Ω source impedance and measurement equipment presenting a 50-Ω load impedance.

GUID-A64CF8DA-2D70-4730-A316-A5B0C1490DAA-low.gifFigure 9-1 Wideband Noninverting Gain Configuration (5 V/V)

Current-feedback amplifiers are highly dependent on the RF feedback resistor for maximum performance and stability. Table 9-2 provides the optimal resistor values for RF and RG at different gains to achieve maximum bandwidth with minimal peaking in the frequency response. Use lower RF values for higher bandwidth. Note that this can cause additional peaking and a reduction in phase margin. Conversely, increasing RF decreases the bandwidth but phase margin increases and stability improves. To gain further insight on the feedback and stability analysis of current-feedback amplifiers like the THS3491, see the Current-feedback Amplifiers section of TI Precision Labs.

Table 9-2 Recommended Resistor Values for Minimum Peaking and Optimal Frequency Response
With RLOAD = 100 Ω
GAIN (V/V)RGT PACKAGEDDA PACKAGE
RG (Ω)RF (Ω)RG (Ω)RF (Ω)
29769762.1k2.1k
5143576200798
1054.949978.7704
202038329.4564