SBOS673D September   2017  – December 2018 OPA2837 , OPA837

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
    1.     Low-Power, Low-Noise, Precision, Single-Ended SAR ADC Driver With True Ground Input and Output Range
  3. 3 Description
    1.     Device Images
  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: OPA837
    5. 6.5  Thermal Information: OPA2837
    6. 6.6  Electrical Characteristics: VS = 5 V
    7. 6.7  Electrical Characteristics: VS = 3 V
    8. 6.8  Typical Characteristics: VS = 5.0 V
    9. 6.9  Typical Characteristics: VS = 3.0 V
    10. 6.10 Typical Characteristics: ±2.5-V to ±1.5-V Split Supply
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagrams
    3. 7.3 Feature Description
      1. 7.3.1 OPA837 Comparison
      2. 7.3.2 Input Common-Mode Voltage Range
      3. 7.3.3 Output Voltage Range
      4. 7.3.4 Power-Down Operation
      5. 7.3.5 Low-Power Applications and the Effects of Resistor Values on Bandwidth
      6. 7.3.6 Driving Capacitive Loads
    4. 7.4 Device Functional Modes
      1. 7.4.1 Split-Supply Operation (±1.35 V to ±2.7 V)
      2. 7.4.2 Single-Supply Operation (2.7 V to 5.4 V)
  8. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1  Noninverting Amplifier
      2. 8.1.2  Inverting Amplifier
      3. 8.1.3  Output DC Error Calculations
      4. 8.1.4  Output Noise Calculations
      5. 8.1.5  Instrumentation Amplifier
      6. 8.1.6  Attenuators
      7. 8.1.7  Differential to Single-Ended Amplifier
      8. 8.1.8  Differential-to-Differential Amplifier
      9. 8.1.9  Pulse Application With Single-Supply Circuit
      10. 8.1.10 ADC Driver Performance
    2. 8.2 Typical Applications
      1. 8.2.1 Active Filters
        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 Implementing a 2:1 Active Multiplexer
        1. 8.2.2.1 Design Requirements
        2. 8.2.2.2 Detailed Design Procedure
      3. 8.2.3 1-Bit PGA Operation
        1. 8.2.3.1 Design Requirements
        2. 8.2.3.2 Detailed Design Procedure
  9. 9 Power Supply Recommendations
  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

8.1.1 Noninverting Amplifier

The OPAx837 can be used as a noninverting amplifier with a signal input to the noninverting input, VIN+. A basic block diagram of the circuit is illustrated in Figure 62. VREF is often ground when split supplies are used.

Calculate the amplifier output according to Equation 1 if VIN = VREF + VSIG.

Equation 1. OPA837 OPA2837 EQ1_vout_los713.gif

The signal gain of the circuit is set by Equation 2, and VREF provides a reference around which the input and output signals swing. Output signals are in-phase with the input signals within the flat portion of the frequency response. For a high-speed, low-noise device such as the OPAx837, the values selected for RF (and RG for the desired gain) can strongly influence the operation of the circuit. For the characteristic curves, the noninverting circuit of Figure 74 shows the test configuration set for a gain of 2 V/V. Table 2 lists the recommended resistor values over gain.

Equation 2. OPA837 OPA2837 Iline1_G_los713.gif
OPA837 OPA2837 sbos673_sch_Non_inverting_GainX2.gifFigure 74. Characterization Test Circuit for Network, Spectrum Analyzer

Table 2 lists the recommended resistor values from target gains of 1 V/V to 10 V/V where standard E96 values are shown. This table controls the RF and RG values to set the resistor noise contribution at approximately 50% of the total output noise power. These values increase the spot noise at the output over what the op amp voltage noise produces by 41%. Lower values reduce the output noise of any design at the cost of more power in the feedback circuit. Using the TINA model and simulation tool shows the impact of different resistor value choices on response shape and noise.

Table 2. Noninverting Recommended Resistor Values

TARGET GAIN (V/V) RF (Ω) RG (Ω) ACTUAL GAIN (V/V) GAIN (dB)
1 0 Open 1.00 0.00
1.5 1190 2370 1.50 3.53
2 2000 2000 2.00 6.02
3 2260 1130 3.00 9.54
4 2370 787 4.01 12.07
5 2490 619 5.02 14.02
6 2550 511 5.99 15.55
7 2610 432 7.04 16.95
8 2670 383 7.97 18.03
9 2670 332 9.04 19.13
10 2670 294 10.08 20.07