STMicroelectronics – TSU10x series : Ultra low-power op amps ideal for conditioning PIR sensor signals

The operational amplifiers in STMicroelectronics’ new TSU10x series draw an extremely low current, enabling designers to optimise their power budget and extend battery lifetime.

The TSU101, TSU102 and TSU104 provide accurate signal conditioning of high-impedance sensors; the TSU104 is particularly well suited for use with Passive Infra-Red (PIR) presence detection sensors.

A PIR sensor may be used in a battery powered system to detect the presence of a person in its field of vision. It is commonly used in security systems, automatic doors and automatic light controls.

The TSU104, which integrates four op-amps inside a single package and offers 8kHz of gain bandwidth, can amplify and filter the small signal generated by a PIR sensor. Its tiny 3mm x 3mm package helps to keep the system’s board footprint to a minimum, and thus helps OEMs to reduce bill-of-materials and manufacturing costs.

Featuring a no-load current of 580nA per channel, the TSU10x op amps draw less current than is supplied by the typical self discharge current of a lithium-ion battery.


  • 5pA maximum input bias current at 25°C
  • Operating-voltage range: 1.5V to 5.5V
  • Unity gain stable
  • Rail-to-rail input and output
  • 2kV ESD rating according to human body model
  • Operating temperature range: -40°C to 85°C


  • Ultra-violet and photo-sensors
  • Electrochemical and gas sensors
  • PIR sensors
  • Battery-current sensing
  • Medical instrumentation



NXP Semiconductor