| As China gradually changes from a large country of electronic components consumption and production to a strong country of design and development,the research and manufacture of domestic electronic components is gradually developing in the direction of high quality and high performance.As the core device of driving circuit in the field of electronic communication,domestic integrated power operational amplifier faces a major challenge under the demand of miniaturization,intelligence and high reliability of products.Therefore,in this paper,in response to the above research background,a domestic integrated power operational amplifier is selected as the research object,and the reliability problem of the product is focused on,the current-limiting protection function is designed and experimentally tested,and the electric-thermal-force coupling simulation analysis and package thermal resistance optimization are studied.The main contents are as follows:(1)Current-limiting protection design of power operational amplifierTo address the problem of the vulnerability of the domestic integrated power amplifier to overcharge stress failure,the current-limiting protection function is designed by combining the internal power chip circuit and package structure of the device.In the theoretical part,the current limiting protection circuit is designed first,and the check resistor is designed according to the structure of op amp circuit and the implementation form of current limiting module.The design of the check resistor is mainly based on ANSYS Q3 D Extractor software,through theoretical calculations to obtain the value of the check resistor and the effective length of the check resistor model,the use of Q3 D software can extract the characteristics of the small size RLCG parameters,the design of the check resistor model to meet the design requirements,and through Cadence simulation to verify the effectiveness of the design of current limiting protection.The experimental verification part is mainly for the power amplifier manufacturing samples with current-limit protection design,and the current-limit protection verification test platform is built.The results show that within a certain applied power consumption range,the sample with current-limit protection design remains unchanged when the output current reaches 6A,and the maximum error in the sample is 0.5% compared with the theoretical design value through statistical analysis of the experimental data.After the experiment,the device without the current-limit protection design is analyzed for failure,and the analysis results show that the design without current-limit protection fails when the chip power supply side and output side generate over-electrical stress at load.(2)Electric-thermal-mechanical coupling simulation analysisBased on ANSYS finite element simulation software,the power amplifier electricthermal-mechanical coupled steady-state simulation model is established by using the circuit principle and Q3 D Extractor software to calculate the chip port equivalent conductivity.By gradually increasing the power consumption,the two power amplifier simulation models before and after the current-limit protection design are compared.The results show that the current density at the output of the model with the current-limit design is smaller than that of the device without the current-limit design,and the maximum chip temperature at the maximum output value is about 10°C lower than that of the model without the current-limit design,and the bonding lead stress strain near the power supply side of the chip and the output side of the chip in the model without the current-limit design is much larger than that of the model with the current-limit design at this moment.The coupled electrical-thermalmechanical simulation model not only analyzes the characteristics of the current-limiting protection design from multiple physical fields,but also provides theoretical guidance for the failure analysis of such power operational amplifiers.(3)Power amplifier TO-3 package thermal performance optimizationBased on the package structure of power operational amplifier,Icepak thermal simulation software is used to optimize the design of seven factors affecting package thermal performance in power amplifier package: chip substrate thickness,chip spacing,solder layer thickness,solder layer area,solder layer material,thermal substrate thickness and thermal substrate material through orthogonal experiments and response surface optimization methods.The optimization results reduce the thermal resistance of the power amplifier package housing from 1.53°C/W to 1.012°C/W,which greatly improves the thermal performance of the power amplifier package.In this paper,through the above reliability design and simulation analysis and optimization of power amplifier,the product avoids the problem of over-electrical stress failure caused by load short circuit or access to abnormal voltage;analyzes the failure mechanism under the action of multi-physical field coupling;optimizes the design of structure and material for the thermal performance of power amplifier package,and improves the reliability of power amplifier. |
