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Nano-power op amp boosts sensing accuracy

With its 1.2 x 1.3mm outline and typical current of 900nA, the TSU111 nano-power op amp from STMicroelectronics is said to help cut the size and energy needs of analogue circuits in a range of applications. These include medical monitors, wearable electronics, gas detectors, pH sensors, infrared motion sensors, and payment tags.

According to the company, it would take more than 25 years to discharge a 220mAh CR2032 cell with the TSU111. The op amp can therefore be designed-in with negligible impact on overall system energy management.

The TSU111 has an input-offset voltage of 15µV and 0.1 to 10Hz noise of 3.6µVp-p, which ensure high accuracy in signal-conditioning circuits.

In addition, the superior gain-bandwidth product of 11.5kHz and the rail-to-rail input stage enable monitoring of environmental and biological signals. The input bias current of 10pA is claimed to help minimise the effects of parasitic currents in sensing devices like gas detectors or photodiodes.

The supply-voltage range of 1.5 to 5V allows the TSU111 to be powered from the same supply rail as logic circuitry thereby simplifying power-supply design and board layout. The low minimum voltage allows the device to run longer as the battery discharges, and simplifies use in equipment powered by energy-harvesting systems, such as photovoltaic cells.

The TSU111 is available in the 1.2 x 1.3mm DFN6 package or 2 x 2.1mm SC70-5 (SOT323-5).

Author
Peggy Lee