Si8540 High-side DC Current Sensor

The Si8540 is a non-isolated, unidirectional high voltage high-side current sense amplifier for use in many applications such as portable PCs, cellular infrastructure equipment, high-end routers, smart battery packs, automotive applications and other power management applications that require current monitoring and current control loops. The Si8540 is an extremely cost-effective and flexible current sensor in an extremely compact 5-pin SOT-23 package.

The Si8540 measures the voltage drop across a sense resistor in the high voltage side of a line. Large values of current can be measured by using a small resistor value and keeping the series voltage drop low across the sense resistor. The Si8540 operates from a single supply +5 to +36 V and has a current output that can be converted to a ground referenced voltage with a resistor ROUT. The amplification factor of the current sense can be adjusted with a choice of external resistor ratios.


  • +5 to +36 V supply operation
  • 0.2% full scale accuracy
  • 90 μA max supply current
  • 9 μA shutdown current
  • -40 to +85 ºC

Si8540 Product Matrix

Part Number Data Sheet Evaluation Kit Package Type Vcm (V) Icc (max) Bidirectional
OPENLPPOL-EVB SOT23-5 5 36 90 No
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