JAJSHC9B May   2019  – October 2021

PRODUCTION DATA

1. 特長
2. アプリケーション
3. 概要
4. Revision History
5. Pin Configuration and Functions
6. Specifications
7. Detailed Description
1. 7.1 Overview
2. 7.2 Functional Block Diagram
3. 7.3 Feature Description
4. 7.4 Device Functional Modes
8. Application and Implementation
1. 8.1 Application Information
2. 8.2 Typical Application
1. 8.2.1 Design Requirements
2. 8.2.2 Detailed Design Procedure
1. 8.2.2.1 Resolver Excitation Input (Op Amp Output)
2. 8.2.2.2 Resolver Output
3. 8.2.2.3 Power Dissipation and Thermal Reliability
3. 8.2.3 Application Curves
9. Power Supply Recommendations
10. 10Layout
11. 11Device and Documentation Support
12. 12Mechanical, Packaging, and Orderable Information

• PWP|14
• PWP|14

#### 8.2.2.3 Power Dissipation and Thermal Reliability

Power dissipation is critical to many industrial and automotive applications. Resolvers are typically chosen over other position feedback techniques because of reliability and accuracy in harsh conditions and high temperatures.

The ALM2402F-Q1 is capable of high output current with power-supply voltages up to 16 V. Internal power dissipation increases when operating at high supply voltages. The power dissipated in the op amp (POPA) is calculated using Equation 6:

Equation 6.

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 7 to include the negative supply voltage instead of the positive.

Equation 7.

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, as shown in Equation 8:

Equation 8.

After the total power dissipation is determined, the junction temperature at the worst expected ambient temperature case must be determined by using Equation 9:

Equation 9.