SBOS859B March   2018  – July 2018 INA1620


  1. Features
  2. Applications
  3. Description
    1.     Device Images
      1.      INA1620 Simplified Internal Schematic
      2.      FFT: 1 kHz, 32-Ω Load, 50 mW
  4. Revision History
  5. Pin Configuration and Functions
    1.     Pin Functions
  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. Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Matched Thin-Film Resistor Pairs
      2. 7.3.2 Power Dissipation
      3. 7.3.3 Thermal Shutdown
      4. 7.3.4 EN Pin
      5. 7.3.5 GND Pin
      6. 7.3.6 Input Protection
    4. 7.4 Device Functional Modes
      1. 7.4.1 Shutdown Mode
      2. 7.4.2 Output Transients During Power Up and Power Down
  8. Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Noise Performance
      2. 8.1.2 Resistor Tolerance
      3. 8.1.3 EMI Rejection
      4. 8.1.4 EMIRR +IN Test Configuration
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
      3. 8.2.3 Application Curves
    3. 8.3 Other Application Examples
      1. 8.3.1 Preamplifier for Professional Microphones
  9. Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Development Support
        1. TINA-TI (Free Software Download)
        2. TI Precision Designs
    2. 11.2 Documentation Support
      1. 11.2.1 Related Documentation
    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

Power Dissipation

The INA1620 is capable of high output current with power-supply voltages up to ±18 V. Internal power dissipation increases when operating at high supply voltages. The power dissipated in the op amp (POPA) is calculated using Equation 1:

Equation 1. INA1620 ai_opapwr_eq.gif

In order to calculate the worst-case power dissipation in the op amp, the ac and dc cases must be considered separately.

In the case of constant output current (dc) to a resistive load, the maximum power dissipation in the op amp occurs when the output voltage is half the positive supply voltage. This calculation assumes that the op amp is sourcing current from the positive supply to a grounded load. If the op amp sinks current from a grounded load, modify Equation 2 to include the negative supply voltage instead of the positive.

Equation 2. INA1620 ai_dcmaxpwr_eq_u.gif

The maximum power dissipation in the op amp for a sinusoidal output current (ac) to a resistive load occurs when the peak output voltage is 2/π times the supply voltage, given symmetrical supply voltages:

Equation 3. INA1620 ai_acmaxpwr_eq.gif

The dominant pathway for the INA1620 to dissipate heat is through the package thermal pad and pins to the PCB. Copper leadframe construction used in the INA1620 improves heat dissipation compared to conventional materials. PCB layout greatly affects thermal performance. Connect the INA1620 package thermal pad to a copper pour at the most negative supply potential. This copper pour can be connected to a larger copper plane within the PCB using vias to improve power dissipation. Figure 45 shows an analogous thermal circuit that can be used for approximating the junction temperature of the INA1620. The power dissipated in the INA1620 is represented by current source PD; the ambient temperature is represented by voltage source 25ºC; and the junction-to-board and board-to-ambient thermal resistances are represented by resistors RθJB and RθBA, respectively. The board-to-ambient thermal resistance is unique to every application. The sum of RθJB and RθBA is the junction-to-ambient thermal resistance of the system. The value for junction-to-ambient thermal resistance reported in the Thermal Information table is determined using the JEDEC standard test PCB. The voltages in the analogous thermal circuit at the points TJ and TPCB represent the INA1620 junction and PCB temperatures, respectively.

INA1620 SBOS859_d305_thermal.epsFigure 45. Approximate Thermal System Model of the INA1620 Soldered to a PCB