SBOS818B December   2016  – November 2018 INA1650 , INA1651

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
    1.     INA165x Simplified Internal Schematic
  3. 3 Description
    1.     CMRR Histogram (5746 Channels)
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1.     Pin Functions
    2.     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
    5. 6.5 Electrical Characteristics:
    6. 6.6 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 Audio Signal Path
      2. 7.3.2 Supply Divider
      3. 7.3.3 Electrical Overstress
      4. 7.3.4 Thermal Shutdown
    4. 7.4 Device Functional Modes
      1. 7.4.1 Single-Supply Operation
  8. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Input Common-Mode Range
      2. 8.1.2 Common-Mode Input Impedance
      3. 8.1.3 Start-Up Time in Single-Supply Applications
      4. 8.1.4 Input AC Coupling
      5. 8.1.5 Supply Divider Capacitive Loading
    2. 8.2 Typical Applications
      1. 8.2.1 Line Receiver for Differential Audio Signals in a Split-Supply System
        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 Differential Line Receiver for Single-Supply Applications
      3. 8.2.3 Floating Single-Ended Input Line Receiver for Ground Loop Noise Reduction
      4. 8.2.4 Floating Single-Ended Input Line Receiver With Differential Outputs
      5. 8.2.5 TRS Audio Interface in Single-Supply Applications
      6. 8.2.6 Differential Line Driver With Single-Ended Input
  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 Device Support
      1. 11.1.1 Development Support
        1. 11.1.1.1 TINA-TI (Free Software Download)
        2. 11.1.1.2 TI Precision Designs
    2. 11.2 Documentation Support
      1. 11.2.1 Related Documentation
    3. 11.3 Related Links
    4. 11.4 Receiving Notification of Documentation Updates
    5. 11.5 Community Resources
    6. 11.6 Trademarks
    7. 11.7 Electrostatic Discharge Caution
    8. 11.8 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

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

8.1.4 Input AC Coupling

The signal path in most audio systems is typically AC-coupled to avoid the propagation of DC voltages, which can potentially damage loudspeakers or saturate power amplifiers. The capacitor values must be selected to pass the desired bandwidth of audio signals. The high-pass corner frequency is calculated with Equation 5:

Equation 5. INA1650 INA1651 AI_EQ_001.gif
INA1650 INA1651 AI_D006.gifFigure 47. AC-Coupling Capacitors Form a High-Pass Filter With INA165x Input Resistors

Although the input resistors of the INA165x are matched typically within 0.01%, large capacitors are usually mismatched. The mismatch in the values of the AC-coupling capacitors causes the corner frequencies at the two signal inputs (IN+ and IN–) to be different, which can degrade CMRR at low frequency. For this reason, TI recommends placing the high-pass corner frequency well below the audio bandwidth and to use a resistor in series with the COM pin (RCOM), as shown in Figure 42 if possible. See the Common-Mode Input Impedance section for more information on placing a resistor in series with the COM pin. Figure 48 shows the effect of a 5% mismatch in the values of the input AC-coupling capacitors with and without an RCOM resistor. Comparing CMRR at 100 Hz: 1-µF AC-coupling capacitors with a 5% mismatch degrade the CMRR to 75 dB, while 10-µF capacitors and a 1-MΩ RCOM resistor shows 92 dB of CMRR.

INA1650 INA1651 C107_SBOS818.pngFigure 48. CMRR Degradation Due to a 5% Mismatch in AC-Coupling Capacitors