National Semicon Introduces 3 op amps with Integrated EMI Filters

National Semiconductor Corp. has introduced three operational amplifiers (op amps) with integrated electromagnetic interference (EMI) filters that maintain the accuracy of analog systems by reducing the effects of radio frequency (RF) interference. The LMV83x op amps deliver highest EMI rejection ratio (EMIRR) of 120 dB, thereby eliminating EMI-induced errors. They also feature 3 MHz unity gain bandwidth while operating on only 240 uA of supply current. This yields a power-to-performance ratio of 80 uA per MHz, which places these devices among National’s PowerWise family of energy-efficient products. The LMV831 single, LMV832 dual and LMV834 quad EMI-hardened op amps reduce development time and board size by minimizing the need for metal shielding, filters and extra components. They are for use in phone accessories, medical instruments, precision weigh scales and other industrial electronic equipment that are sensitive to electromagnetic disturbances in noisy environments. Using an LMV83x op amp would only reduce resolution by 0.2-bits. A wide range of applications can benefit from EMI protection, including filters/buffers, photodiode preamp and piezoelectric sensors.



The LMV831 single, LMV832 dual and LMV834 quad op amps feature CMOS inputs, a maximum input offset voltage of 1 mV, a rail-to-rail output stage and an input common-mode voltage range that includes ground. These devices provide a common-mode rejection ratio (CMRR) and a power supply rejection ratio (PSRR) of 93 dB. The LMV83x devices maintain stability for capacitive loads as large as 200 pF and offer a wide temperature range of -40 degrees C to 125 degrees C. The LMV831 is offered in a 5-pin SC70 package, while the LMV832 is offered in an 8-pin MSOP package and the LMV834 is offered in a 14-pin TSSOP package.