SBOS079C March   1999  – February 2023 OPA2277 , OPA277 , OPA4277

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and 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: OPA277
    5. 6.5 Thermal Information: OPA2277
    6. 6.6 Thermal Information: OPA4277
    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 Offset Voltage Adjustment
      3. 7.3.3 Input Protection
      4. 7.3.4 Input Bias Current Cancellation
      5. 7.3.5 EMI Rejection Ratio (EMIRR)
        1. 7.3.5.1 EMIRR IN+ Test Configuration
    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 Second-Order, Low-Pass Filter
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
        3. 8.2.1.3 Application Curve
      2. 8.2.2 Load Cell Amplifier
      3. 8.2.3 Thermocouple Low-Offset, Low-Drift Loop Measurement With Diode Cold Junction Compensation
    3. 8.3 Power Supply Recommendations
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
        1. 8.4.1.1 DRM Package (8-Pin VSON)
      2. 8.4.2 Layout Example
  9. 9 Device and Documentation Support
    1. 9.1 Device Support
      1. 9.1.1 Development Support
        1. 9.1.1.1 PSpice® for TI
        2. 9.1.1.2 TINA-TI™ Simulation Software (Free Download)
        3. 9.1.1.3 DIP-Adapter-EVM
        4. 9.1.1.4 DIYAMP-EVM
        5. 9.1.1.5 TI Reference Designs
        6. 9.1.1.6 Filter Design Tool
    2. 9.2 Documentation Support
      1. 9.2.1 Related Documentation
    3. 9.3 Receiving Notification of Documentation Updates
    4. 9.4 Support Resources
    5. 9.5 Trademarks
    6. 9.6 Electrostatic Discharge Caution
    7. 9.7 Glossary
  10. 10Mechanical, Packaging, and Orderable Information

Package Options

Refer to the PDF data sheet for device specific package drawings

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

7.3.5 EMI Rejection Ratio (EMIRR)

The electromagnetic interference (EMI) rejection ratio, or EMIRR, describes the EMI immunity of operational amplifiers. An adverse effect that is common to many operational amplifiers is a change in the offset voltage as a result of RF signal rectification. An operational amplifier that is more efficient at rejecting this change in offset as a result of EMI has a higher EMIRR and is quantified by a decibel value. Measuring EMIRR can be performed in many ways, but this report provides the EMIRR IN+, which specifically describes the EMIRR performance when the RF signal is applied to the noninverting input pin of the operational amplifier. In general, only the noninverting input is tested for EMIRR for the following three reasons:

  1. Operational amplifier input pins are known to be the most sensitive to EMI, and typically rectify RF signals better than the supply or output pins.
  2. The noninverting and inverting operational amplifier inputs have symmetrical physical layouts and exhibit nearly matching EMIRR performance.
  3. EMIRR is easier to measure on noninverting pins than on other pins because the noninverting input terminal can be isolated on a printed circuit board (PCB). This isolation allows the RF signal to be applied directly to the noninverting input terminal with no complex interactions from other components or connecting PCB traces.
A more formal discussion of the EMIRR IN+ definition and test method is provided in the EMI Rejection Ratio of Operational Amplifiers application note, available for download at www.ti.com. #SBOS0795497 shows the EMIRR IN+ of the OPA277 plotted versus frequency.

GUID-E95B504C-7DA4-4DC7-A118-9E44C8223F6A-low.gifFigure 7-4 OPA277 EMIRR IN+ vs Frequency

If available, any dual and quad operational amplifier device versions have nearly similar EMIRR IN+ performance. The OPA277 unity-gain bandwidth is 1 MHz. EMIRR performance below this frequency denotes interfering signals that fall within the operational amplifier bandwidth.

Table 7-1 shows the EMIRR IN+ values for the OPA277 at particular frequencies commonly encountered in real-world applications. Applications listed in Table 7-1 can be centered on or operated near the particular frequency shown. This information is of special interest to designers working with these types of applications, or working in other fields likely to encounter RF interference from broad sources, such as the industrial, scientific, and medical (ISM) radio band.

Table 7-1 OPA277 EMIRR IN+ for Frequencies of Interest
FREQUENCY APPLICATION/ALLOCATION EMIRR IN+
400 MHz Mobile radio, mobile satellite-space operation, weather, radar, UHF 59.1 dB
900 MHz GSM, radio com-nav-GPS (to 1.6 GHz), ISM, aeronautical mobile, UHF 77.9 dB
1.8 GHz GSM, mobile personal comm. broadband, satellite, L-band 91.3 dB
2.4 GHz 802.11b/g/n, Bluetooth®, mobile personal comm, ISM, amateur radio-satellite, S-band 93.3 dB
3.6 GHz Radiolocation, aero comm-nav, satellite, mobile, S-band 105.9 dB
5.0 GHz 802.11a/n, aero comm-nav, mobile comm, space-satellite operation, C-band 107.5 dB