National Semi intros zero-drift amplifier

HONG KONG: Analog power management technology major National Semiconductor Corp today announced the launch what is said to be the industry’s first 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, said a press release. This diagnostic capability prevents circuit shutdowns in medical instruments, precision weigh scales, pressure sensors and motor control systems.

National Semiconductor said the LMP8358 uses patented techniques to measure and continuously correct its input offset voltage (5 uV typical), eliminating offset drift over time and temperature, as well as the effect of 1/f noise.

The LMP8358 is equipped with electromagnetic interference (EMI) suppression filters to reduce unwanted radio frequency (RF) interference from external sources, such as cell phones or nearby antennas. Additional filtering can be added with one external capacitor, the release added.

The LMP8358 is built on National’s CMOS7-5V process technology and provides an optimized signal path solution for precision systems when combined with the 16-bit ADC161S626 or 14-bit ADC141S626 analog-to-digital converters.

The LMP8358 is said to provide glitch-free transitions between gain settings, which 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 per cent typical gain error.

Supplied in 14-pin SOIC and 14-pin TSSOP packages, the LMP8358 operates from a single 2.7V to 5V supply and operates over a wide temperature range of -40 degrees C to 125 degrees C. The amplifier provides 10 uV maximum offset voltage and 50 nV/C maximum offset voltage drift. It features a gain bandwidth (GBW) of 8 MHz while consuming only 1.7 mA of supply current.

According to National Semiconductor, a power-conserving shutdown mode reduces current consumption to less than 1 uA. The LMP8358’s registers allow designers to program the chip’s bandwidth, shutdown and fault detection circuitry. Designers also can “daisy chain” multiple LMP8358 ICs.