NJM2904BR Quad Op Amp with High RF Noise Immunity

Nisshinbo Micro Devices' op amps and comparators are used for automotive applications such as amplifying small signals from various sensors and current detection. When external electromagnetic noises (EMI) interferes with the op amp used in automotive electronic control units (ECU) beyond the operating frequency, the output voltage will fluctuate and the ECU will malfunction. This requires an op amp with high EMC performance and high immunity to RF noise interference.

The EMI of an op amp can intrude from the input terminal with weak EMI immunity, so EMC countermeasures of most products were taken only for the input terminals. Compared to taking similar countermeasures onboard (near the target IC), these products provide benefits such as a reduction in the mounting area and component costs due to configuring filters and margin enhancement against oscillation. Considering the noises superimposed on the wire harness intruding from the power supply terminal of the amp, the interference countermeasure is not complete.

Nisshinbo Micro Devices takes optimal EMC countermeasures for each stage based on the exhaustive analysis of the EMI noise intrusion path to each stage circuit of the op amp, the effect on the circuit operation, and the mechanism of the malfunction. The immunity (EMS) of the power supply terminal and the input terminal were successfully improved to the industry-leading level. The devices provide stable and high EMC performance. They are countermeasures for the IC internal circuits, making it hard to be affected by the chip layout and the assembly conditions. By minimizing the risk of design rework after the noise evaluation, these products contribute to the reduction of customers' total development costs.