National Semiconductor has added on-chip diagnostic capabilities to its range of instrumentation amplifiers.
Its first device is a zero-drift, programmable instrumentation amplifier, the LMP8358 which is intended for use in pressure and thermocouple bridge measurements.
It can be used 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,” said the supplier.
The LMP8358 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/sqrt Hz.
There is programmable frequency compensation and the chip’s offset compensation circuit helps avoid distortion and aliasing for signals lower than 12kHz of bandwidth.
The LMP8358 is built on National’s CMOS7-5V process technology.
Gain settings can be programmed to 10, 20, 50, 100, 200, 500 or 1000 through a serial peripheral interface (SPI) or parallel interface.
“All gain settings have less than 0.1% typical gain error,” said the company.