SBOS235F March   2002  – April 2018 OPA2357 , OPA357

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Simplified Schematic
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1.     Pin Functions
  6. 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: VS = +2.7-V to +5.5-V Single-Supply
    6. 6.6 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1  OPAx357 Comparison
      2. 7.3.2  Operating Voltage
      3. 7.3.3  Enable Function
      4. 7.3.4  Rail-to-Rail Input
      5. 7.3.5  Rail-to-Rail Output
      6. 7.3.6  Output Drive
      7. 7.3.7  Video
      8. 7.3.8  Wideband Video Multiplexing
      9. 7.3.9  Driving Analog-to-Digital Converters
      10. 7.3.10 Capacitive Load and Stability
      11. 7.3.11 Wideband Transimpedance Amplifier
    4. 7.4 Device Functional Modes
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Applications
      1. 8.2.1 Transimpedance Amplifier
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
          1. 8.2.1.2.1 Custom Design With WEBENCH® Tools
          2. 8.2.1.2.2 OPAx357 Design Procedure
            1. 8.2.1.2.2.1 Optimizing the Transimpedance Circuit
        3. 8.2.1.3 Application Curve
      2. 8.2.2 High-Impedance Sensor Interface
      3. 8.2.3 Driving ADCs
      4. 8.2.4 Active Filter
  9. 9 Power Supply Recommendations
    1. 9.1 Power Dissipation
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Development Support
        1. 11.1.1.1 Custom Design With WEBENCH® Tools
    2. 11.2 Documentation Support
      1. 11.2.1 Related Documentation
    3. 11.3 Related Links
    4. 11.4 Receiving Notification of Documentation Updates
    5. 11.5 Community Resources
    6. 11.6 Trademarks
    7. 11.7 Electrostatic Discharge Caution
    8. 11.8 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

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

8.2.4 Active Filter

The OPAx357 family of devices is designed for active filter applications that require a wide bandwidth, fast slew rate, low-noise, single-supply operational amplifier. Figure 46 shows a 500-kHz, second-order, low-pass filter using the multiple-feedback (MFB) topology. The components are selected to provide a maximally-flat Butterworth response. Beyond the cutoff frequency, roll-off is –40 dB/dec. The Butterworth response is designed for applications requiring predictable gain characteristics, such as the antialiasing filter used in front of an A/D converter.

One point to note when considering the MFB filter is that the output is inverted relative to the input. If this inversion is not required, or not desired, a noninverting output can be achieved through one of the following options:

  1. Adding an inverting amplifier
  2. Adding an additional second-order MFB stage
  3. Using a noninverting filter topology, such as the Sallen-Key (see Figure 47).

MFB and Sallen-Key, low-pass and high-pass filter synthesis is accomplished using TI’s FilterPro™ program. This software is available as a free download on www.ti.com.

OPA357 OPA2357 ai_2order_lopass_filt_sbos492.gifFigure 46. Second-Order, Butterworth, 500-kHz, Low-Pass Filter
OPA357 OPA2357 ai_sallen_key_sbos492.gifFigure 47. OPAx357 Configured as a Three-Pole, 20-kHz, Sallen-Key Filter