National Semiconductor has introduced a zero-drift, programmable instrumentation amplifier with on-chip diagnostics. The LMP8358 simplifies pressure and thermocouple bridge measurements by allowing users to detect shorts, open circuits, and degraded source connections in remote industrial applications. This diagnostic capability prevents circuit shutdowns in medical instruments, precision weigh scales, pressure sensors, and motor control systems. The device uses patented techniques to measure and continuously correct its input offset voltage (5µV typical), eliminating offset drift over time and temperature, as well as the effect of 1/f noise. This leads to a flat noise spectrum of 27nV/sqrtHz. The device's programmable frequency compensation enables programmable bandwidths, and its offset compensation circuit does not introduce distortion and aliasing for signals lower than 12kHz of bandwidth. The device is equipped with electromagnetic interference suppression filters to reduce unwanted radio frequency interference from external sources, such as cell phones or nearby antennas. The device is built using the company's CMOS7-5V process technology.
