JAJSJW5 June   2024 OPA596

ADVANCE INFORMATION  

  1.   1
  2. 1 特長
  3. 2 アプリケーション
  4. 3 概要
  5. 4 Pin Configuration and Functions
  6. 5 Specifications
    1. 5.1 Absolute Maximum Ratings
    2. 5.2 ESD Ratings
    3. 5.3 Recommended Operating Conditions
    4. 5.4 Thermal Information
    5. 5.5 Electrical Characteristics
  7. 6 Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagram
    3. 6.3 Feature Description
      1. 6.3.1 Mux-Friendly Inputs
      2. 6.3.2 Thermal Protection
      3. 6.3.3 Slew Boost
      4. 6.3.4 Overload Recovery
    4. 6.4 Device Functional Modes
  8. 7 Application and Implementation
    1. 7.1 Application Information
    2. 7.2 Typical Applications
      1. 7.2.1 Bridge-Connected Piezoelectric Driver
        1. 7.2.1.1 Design Requirements
        2. 7.2.1.2 Detailed Design Procedure
      2. 7.2.2 DAC Output Gain and Buffer
        1. 7.2.2.1 Design Requirements
        2. 7.2.2.2 Detailed Design Procedure
      3. 7.2.3 Single-Supply Piezoelectric Driver
      4. 7.2.4 High-Side Current Sense
      5. 7.2.5 High-Voltage Instrumentation Amplifier
      6. 7.2.6 Composite Amplifier
    3. 7.3 Power Supply Recommendations
    4. 7.4 Layout
      1. 7.4.1 Layout Guidelines
        1. 7.4.1.1 Thermal Considerations
      2. 7.4.2 Layout Example
  9. 8 Device and Documentation Support
    1. 8.1 ドキュメントの更新通知を受け取る方法
    2. 8.2 サポート・リソース
    3. 8.3 Trademarks
    4. 8.4 静電気放電に関する注意事項
    5. 8.5 用語集
  10. 9 Revision History
  11. 10Mechanical, Packaging, and Orderable Information
    1. 10.1 Tape and Reel Information

7.4.1.1 Thermal Considerations

Through normal operation, the op amps can self-heat. Self-heating is a natural increase in the die junction temperature that occurs in every amplifier. This self-heating is a result of several factors, including quiescent power consumption, package thermal resistance, PCB layout, and device operating conditions.

Operate the OPAx596 within the rated junction temperature, TJ, range to avoid thermal shutdown. Use the Equation 2 to determine the estimated TJ

Equation 2. T J = P D   ×   θ J A + T A

In a quiescent state, PD is given by the product of the power supply and the quiescent current of the op amp. Equation 3 shows the calculation of TJ for the OPAx596 assuming an 85V power supply is used and an operating temperature of 25°C.

Equation 3. T J = 85 V   × 490 μ A × 165.4 ° C W + 25 ° C
Equation 4. T J = 31.89 ° C

The low power consumption of the OPAx596 causes minimal self-heating even in a small SOT23-5 package as given by Equation 4. In a loaded condition, PD is equal to addition of the quiescent power, PDQ and the power dissipated by the output stage, PDL. The worst-case condition is given when the output voltage is equal to ½ of either supply rail (assuming symmetrical supplies, V+ and V-). In a worst-case condition, PDL is given by Equation 5.

Equation 5. P D L = ( V + ) 2 4 × R L

For example, assume the OPAx596 is powered with bipolar ±42.5V power supplies and drives a 5kΩ load, RL, to ground. The maximum increase in TJ is expected to be about 22°C as given by Equation 6. In this example, to keep the op amp within the Absolute Maximum Ratings, operate in TA well under 128°C to account for different factors.

Equation 6. ∆ T J = 41.7 m W + 90.3 m W × 165.4 ° C W