SBOS492F June   2009  – May 2018 OPA2354A-Q1 , OPA354A-Q1 , OPA4354-Q1

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Simplified Schematic
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1.     Pin Functions: OPA354A-Q1
    2.     Pin Functions: OPA2354A-Q1
    3.     Pin Functions: OPA4354-Q1
  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: OPA354A-Q1
    5. 6.5 Thermal Information: OPA2354A-Q1
    6. 6.6 Thermal Information: OPA4354A-Q1
    7. 6.7 Electrical Characteristics
    8. 6.8 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 Operating Voltage
      2. 7.3.2 Rail-to-Rail Input
      3. 7.3.3 Rail-to-Rail Output
      4. 7.3.4 Output Drive
      5. 7.3.5 Video
      6. 7.3.6 Driving Analog-to-Digital Converters
      7. 7.3.7 Capacitive Load and Stability
      8. 7.3.8 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 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 Documentation Support
      1. 11.1.1 Related Documentation
    2. 11.2 Related Links
    3. 11.3 Receiving Notification of Documentation Updates
    4. 11.4 Community Resources
    5. 11.5 Trademarks
    6. 11.6 Electrostatic Discharge Caution
    7. 11.7 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 OPAx354-Q1 family of devices is designed for active filter applications that require a wide bandwidth, fast slew rate, low-noise, single-supply operational amplifier. Figure 42 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 anti-aliasing filter used in front of an ADC.

One point to observe 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 43).

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.

OPA354A-Q1 OPA2354A-Q1 OPA4354-Q1 ai_2order_lopass_filt_sbos492.gifFigure 42. Second-Order Butterworth 500-kHz Low-Pass Filter
OPA354A-Q1 OPA2354A-Q1 OPA4354-Q1 ai_sallen_key_sbos492.gifFigure 43. OPAx354-Q1 Configured as a Three-Pole, 20-kHz, Sallen-Key Filter