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

7.3.11 Wideband Transimpedance Amplifier

Wide bandwidth, low input bias current, and low input voltage and current noise make the OPA357 an ideal wideband photodiode transimpedance amplifier for low-voltage single-supply applications. Low-voltage noise is important because photodiode capacitance causes the effective noise gain of the circuit to increase at high frequency.

The key elements to a transimpedance design, as shown in Figure 40, are the expected diode capacitance (including the parasitic input common-mode and differential-mode input capacitance (2 + 2)pF for the OPA357), the desired transimpedance gain (RF), and the gain bandwidth product (GBP) for the OPA357 (100 MHz). With these three variables set, the feedback capacitor value (CF) can be set to control the frequency response.

OPA357 OPA2357 OPA357_SBOS235_transimpedance_amplifier.gifFigure 40. Transimpedance Amplifier

To achieve a maximally flat 2nd-order Butterworth frequency response, set the feedback pole to:

Equation 1. OPA357 OPA2357 eq_butterworth_sbos235.gif

Typical surface-mount resistors have a parasitic capacitance of approximately 0.2 pF that must be deducted from the calculated feedback capacitance value.

Bandwidth is calculated by:

Equation 2. OPA357 OPA2357 eq_bandwidth_sbos235.gif

For even higher transimpedance bandwidth, the high-speed CMOS OPA355 (200-MHz GBW) or the OPA655 (400-MHz GBW) can be used.