SBOS196I December   2001  – February 2024 OPA656

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Device Comparison Table
  6. 5 Pin Configuration and Functions
  7. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Electrical Characteristics: High Grade DC Specifications
    7. 6.7 Typical Characteristics: VS = ±5 V
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Feature Description
      1. 7.2.1 Input and ESD Protection
    3. 7.3 Device Functional Modes
  9. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Wideband, Noninverting Operation
      2. 8.1.2 Wideband, Inverting Gain Operation
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
      3. 8.2.3 Application Curves
    3. 8.3 Power Supply Recommendations
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
        1. 8.4.1.1 Demonstration Fixtures
        2. 8.4.1.2 Thermal Considerations
      2. 8.4.2 Layout Example
  10. 9 Device and Documentation Support
    1. 9.1 Documentation Support
      1. 9.1.1 Related Documentation
    2. 9.2 Receiving Notification of Documentation Updates
    3. 9.3 Support Resources
    4. 9.4 Trademarks
    5. 9.5 Electrostatic Discharge Caution
    6. 9.6 Glossary
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information

Package Options

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • D|8
  • DBV|5
Thermal pad, mechanical data (Package|Pins)
Orderable Information

8.1.1 Wideband, Noninverting Operation

The OPA656 provides a unique combination of a broadband, unity gain stable, voltage-feedback amplifier with the dc precision of a trimmed JFET-input stage. The very high gain bandwidth product (GBP) of 230 MHz can be used to either deliver high signal bandwidths for low-gain buffers, or to deliver broadband, low-noise transimpedance bandwidth to photodiode-detector applications. To achieve the full performance of the OPA656, careful attention to printed-circuit-board (PCB) layout and component selection is required, as discussed in the remaining sections of this data sheet.

Figure 8-1 shows the noninverting gain of +2 V/V circuit used as the basis for most of the Typical Characteristics. Most of the curves were characterized using signal sources with 50‑Ω driving impedance, and with measurement equipment presenting a 50‑Ω load impedance. In Figure 8-1, the 50‑Ω shunt resistor at the VI terminal matches the source impedance of the test generator, while the 50‑Ω series resistor at the VO terminal provides a matching resistor for the measurement equipment load. Generally, data sheet voltage swing specifications are at the output pin (VO in Figure 8-1) while output power specifications are at the matched 50‑Ω load. The total 100-Ω load at the output combined with the 500‑Ω total feedback network load, presents the OPA656 with an effective output load of 83 Ω for the circuit of Figure 8-1.

GUID-8D6F6BC7-8B60-4039-BC26-097B98E7E646-low.gifFigure 8-1 Noninverting G = +2 V/V Specifications and Test Circuit

Voltage-feedback operational amplifiers, unlike current feedback products, can use a wide range of resistor values to set the gain. To retain a controlled frequency response for the noninverting voltage amplifier of Figure 8-1, ensure that the parallel combination of RF || RG is always < 200 Ω. In the noninverting configuration, the parallel combination of RF || RG forms a pole with the parasitic input capacitance at the inverting node of the OPA656 (including layout parasitics). For best performance, ensure this pole is at a frequency greater than the closed-loop bandwidth for the OPA656. For this reason, TI recommends a direct short from the output to the inverting input for the unity-gain follower application.