High RF Noise Immunity Operational Amplifiers
with Excellent EMC Performance
with Excellent EMC Performance
Annoyed by Failing RF Noise Immunity Testing after Finishing Board Design?
Operational amplifiers and comparators are widely used for automotive applications such as amplifying small signals from various sensors and current detection. When the operational amplifier used in automotive ECU (Electronic Control Unit) is interfered by the external electromagnetic noises (EMI) beyond the operating frequency, the output voltage will fluctuate, and the ECU will be malfunction. For this reason, operational amplifiers with high EMC performance such as one highly immune to RF noise interference are required.
Importance and Problems on RF Noise Immunity
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The noise immunity are generally evaluated in the final stage of vehicle development. If a problem is discovered, the design of ECU pattern and the selection of mounted parts return from the analysis to the countermeasures. It will affect the design man-hours. The multi-function of vehicle increases the number of installed ECUs. However, the increase of smart phones and electronic devices with communication functions has made electromagnetic interference become very serious. Therefore, there are stronger demands for operational amplifiers with high EMC performance.
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Reduction of Customers' Design Workload Thanks to Industry-leading EMC Performance.
IEC 62132-4 / ED-5008 Compliant Benchmarks to Prevent Design Rework.
In addition to the input terminal, the RF noise immunity (EMS) of the power-supply terminal has also been enhanced
The EMI of an operational amplifier generally intrudes from the input terminal with weak EMI immunity, so the EMC countermeasures of most products have been taken only for the input terminals. Compared to taking similar countermeasures on board (near the target IC), these products provide certain benefits, such as reduction in mounting area and component costs due to configuring filters, and enhancement of margin against oscillation. However, considering the noises superimposed on the wire harness intrude from the power supply terminal of the amplifier, the interference countermeasure is not complete.
Nisshinbo Micro Devices took optimal EMC countermeasures for each stage based on the exhaustive analysis of the EMI noise intrusion path to each stage circuit of the operational amplifier, the effect on the circuit operation, and the mechanism of the malfunction. Therefore, the immunity (EMS) of the power-supply terminal as well as the input terminal was successfully improved to the industry-leading level. Since it is a countermeasure for IC internal circuits, it is hard to be affected by the chip layout and the assembly conditions, provides stable and high EMC performance. By minimizing the risk of design rework after the noise evaluation, our products contribute to the reduction of customers' total development costs.
Achieve industry-leading (RF noise) immunity as a single component by the noise evaluation based on IEC 62132-4
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Operational amplifiers are used for various applications, and the same operational amplifiers are installed in various electrical and electronic devices. Since the required EMC standards are different with every situation, it is very important to compare and evaluate the EMI immunity of a single operational amplifier properly.
The NJM2904B / NJM2902B have been compared / evaluated based on the international standard IEC 62132-4 and JEITA standard ED-5008, and confirmed that they are the industry-leading level. So you can use them with confidence from new design to consideration of replacement.
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DPI evaluation results based on IEC 62132-4, ED-5008
The following figures show DPI evaluation results for an input terminal (left) and a power-supply terminal (right). The test conditions are as follows: the circuit configuration is a voltage follower, the maximum forward power is 27 dBm, and a failure criterion is defined as an output voltage fluctuation of 300 mV. These figures show the maximum forward power at which operational amplifiers do not malfunction, with forward power on the vertical axis and frequency on the horizontal axis. The higher the value on the figures, the higher the immunity. The NJM2904B and NJM2902B have the industry's highest level of EMC performance for both input and power-supply terminals.
- IEC 62132-4 (IEC)
It is one of the IEC 62132 series that measure the EMC (immunity) of semiconductors. DPI (Direct Power Injection) testing according to IEC 62132-4 is a test that evaluates immunity performance by injecting power into the IC terminal with capacitive coupling and measure the limit power when the IC operates normally. - ED-5008 (JEITA)
It is a JEITA standard, EMC Performance equivalence test of semiconductor. It is a standard for evaluating the EMC performance differences of semiconductors, and the evaluation method conforms to IEC 62132-4.
