SBOS919C August   2019  – August 2020 OPA862

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
    5. 6.5 Electrical Characteristics: VS = ±2.5 V to ±5 V
    6. 6.6 Typical Characteristics: VS = ±5 V
    7. 6.7 Typical Characteristics: VS = ±2.5 V
    8. 6.8 Typical Characteristics: VS = 1.9 V, –1.4 V
    9. 6.9 Typical Characteristics: VS = 1.9 V, –1.4 V to ±5 V
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Input and ESD Protection
      2. 7.3.2 Anti-Phase Reversal Protection
      3. 7.3.3 Precision and Low Noise
    4. 7.4 Device Functional Modes
      1. 7.4.1 Split-Supply Operation (±1.5 V to ±6.3 V)
      2. 7.4.2 Single-Supply Operation (3 V to 12.6 V)
  8. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Single-Ended-to-Differential Gain of 4 V/V
    2. 8.2 Typical Applications
      1. 8.2.1 Single-Ended to Differential with 2.5-V Output Common-Mode Voltage
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
        3. 8.2.1.3 Application Curves
      2. 8.2.2 Transimpedance Amplifier Configuration
        1. 8.2.2.1 Design Requirements
        2. 8.2.2.2 Detailed Design Procedure
        3. 8.2.2.3 Application Curves
      3. 8.2.3 DC Level-Shifting
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Examples
  11. 11Device and Documentation Support
    1. 11.1 Documentation Support
      1. 11.1.1 Related Documentation
    2. 11.2 Receiving Notification of Documentation Updates
    3. 11.3 Support Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

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

8.2.2 Transimpedance Amplifier Configuration

With recent advancements in light-sensing technology, transimpedance (TIA) applications are becoming popular, ranging in signal bandwidth needs from tens of kHz to hundreds of MHz. Because the current output of the photodiode in these TIA applications is unipolar, a key challenge in interfacing with the fully differential input analog-to-digital converters (ADCs) is maximizing the differential signal to the ADC in order to maximize the signal-to-noise ratio (SNR).

As illustrated in the output waveform of Figure 8-6, only half the differential output signal swing of the FDA is available. On the contrary, by using the OPA862 as the TIA stage, a single-device interface to the ADC can be designed that also allows the full differential swing to the ADC and set the desired output common-mode as shown in Figure 8-5. VREF is used to set the output common-mode voltage and VDC is used to DC shift the outputs such that for a zero photodiode current, VOD (equal to VOUT+ – VOUT–) is at one of the peaks of the desired differential peak-to-peak swing. Whether the VOD peak at the zero photodiode current is at a high or low peak is determined by the direction of current through RF in the presence of the photodiode signal current.

GUID-58FAE4C6-24E2-4BA8-91A9-927B199A6B62-low.gifFigure 8-5 Improved TIA Signal Chain With the OPA862
GUID-A749B1AC-CA50-40C4-9D71-AF447B29C3C7-low.gifFigure 8-6 Conventional TIA Signal Chain