SLOSEE7 May   2025 OPA810-Q1

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Device Comparison Table
  6. 5 Pin Configuration and Functions
  7. 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: 24V
    6. 6.6 Electrical Characteristics: 5V
    7. 6.7 Typical Characteristics: VS = 24V
    8. 6.8 Typical Characteristics: VS = 5V
    9. 6.9 Typical Characteristics: ±2.375V to ±12V Split Supply
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Architecture
      2. 7.3.2 ESD Protection
    4. 7.4 Device Functional Modes
      1. 7.4.1 Split-Supply Operation (±2.375V to ±13.5V)
      2. 7.4.2 Single-Supply Operation (4.75V to 27V)
  9. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Amplifier Gain Configurations
      2. 8.1.2 Selection of Feedback Resistors
      3. 8.1.3 Noise Analysis and the Effect of Resistor Elements on Total Noise
    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
        3. 8.2.1.3 Application Curves
      2. 8.2.2 Multichannel Sensor Interface
    3. 8.3 Power Supply Recommendations
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
        1. 8.4.1.1 Thermal Considerations
      2. 8.4.2 Layout Example
  10. 9 Device and Documentation Support
    1. 9.1 Documentation Support
      1. 9.1.1 Related Documentation
    2. 9.2 Receiving Notification of Documentation Updates
    3. 9.3 Support Resources
    4. 9.4 Trademarks
    5. 9.5 Electrostatic Discharge Caution
    6. 9.6 Glossary
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information

Package Options

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • DBV|5
Thermal pad, mechanical data (Package|Pins)
Orderable Information

8.1.3 Noise Analysis and the Effect of Resistor Elements on Total Noise

The OPA810-Q1 provides a low input-referred broadband noise voltage density of 6.3nV/√Hz while requiring a low 3.7mA quiescent supply current. To take full advantage of this low input noise, careful attention to the other possible noise contributors is required. Figure 8-10 shows the operational amplifier noise analysis model with all the noise terms included. In this model, all the noise terms are taken to be noise voltage or current density terms in nV/√Hz or pA/√Hz.

OPA810-Q1 Operational-Amplifier Noise-Analysis Model Figure 8-10 Operational-Amplifier Noise-Analysis Model

The total output-spot-noise voltage is computed as the square root of the squared contributing terms to the output noise voltage. This computation adds all the contributing noise powers at the output by superposition, then calculates the square root to get back to a spot noise voltage. Figure 8-10 shows the general form for this output noise voltage using the terms shown in Equation 7.

Equation 7. EO = (ENI2 +(IBNRS)2+4kTRS )NG2+(IBIRF)2 +4kTRFNG 

Dividing this expression by the noise gain (NG = 1 + RF / RG) shows the equivalent input referred spot noise voltage at the noninverting input; see Equation 8.

Equation 8. EN = ENI2 +(IBNRS)2+4kTRS+(IBIRFNG)2 +4kTRFNG 

Substituting large resistor values into Equation 8 can quickly dominate the total equivalent input referred noise. A source impedance on the noninverting input of 2kΩ adds a Johnson voltage noise term similar to that of the amplifier (6.3nV/√Hz).

Table 8-1 compares the noise contributions from the various terms when the OPA810-Q1 is configured in a noninverting gain of 5V/V as Figure 8-11 shows. Two cases are considered where the resistor values in case 2 are 10 × the resistor values in case 1. The total output noise in case 1 is 34nV/√Hz, whereas the noise in case 2 is 51.5nV/√Hz. The large value resistors in case 2 dilute the benefits of selecting a low-noise amplifier like the OPA810-Q1. To minimize total system noise, reduce the size of the resistor values. This reduction increases the amplifiers output load and results in a degradation of distortion performance. The increased loading increases the dynamic power consumption of the amplifier. The circuit designer must make the appropriate tradeoffs to maximize the overall performance of the amplifier to match the system requirements.

OPA810-Q1 Comparing Noise Contributors: Two Cases With the Amplifier in a Noninverting Gain of 5V/V Figure 8-11 Comparing Noise Contributors: Two Cases With the Amplifier in a Noninverting Gain of 5V/V
Table 8-1 Comparing Noise Contributions for the Circuit in Figure 8-11
NOISE SOURCE OUTPUT NOISE EQUATION CASE 1 CASE 2
NOISE SOURCE VALUE VOLTAGE NOISE CONTRIBUTION (nV/√Hz) NOISE POWER CONTRIBUTION (nV2/Hz) CONTRIBUTION (%) NOISE SOURCE VALUE VOLTAGE NOISE CONTRIBUTION (nV/√Hz) NOISE POWER CONTRIBUTION (nV2/Hz) CONTRIBUTION (%)
Source resistor, RS ERS (1 + RF /RG) 1.82nV/√Hz 9.1 82.81 7.15 5.76nV/√Hz 28.8 829.44 31.29
Gain resistor, RG ERG (RF / RG) 2.04nV/√Hz 8.16 66.59 5.75 6.44nV/√Hz 25.76 663.58 25.03
Feedback resistor, RF ERF 4.07nV/√Hz 4.07 16.57 1.43 12.87nV/√Hz 12.87 165.64 6.25
Amplifier voltage noise, ENI ENI (1 + RF / RG) 6.3nV/√Hz 31.5 992.25 85.67 6.3nV/√Hz 31.5 992.25 37.43
Inverting current noise, IBI IBI (RF || RG) 5fA/√Hz 5.0E-3 — — 5fA/√Hz 50E-3 — —
Noninverting current noise, IBN IBNRS (1 + RF/ RG) 5fA/√Hz 1.0E-3 — — 5fA/√Hz 10E-3 — —