The KTS1681A overvoltage protection device features an ultra-low 28mΩ (typical) on-resistance high current integrated MOSFET which actively protects low-voltage systems from voltage supply faults up to +28VDC. An internal clamp protects the device from surges up to 100V.

An input voltage exceeding the overvoltage threshold will cause the internal MOSFET to turn off, preventing excessive voltage from damaging downstream devices. When the OVLO input set below the external OVLO select voltage, the KTS1681A automatically chooses the internal fixed OVLO threshold, preset to 5.95V (typical). The overvoltage protection threshold can be adjusted with optional resistor divider to a voltage between 4V and 22V.

The KTS1681A is protected against over-current faults by an internal over-temperature protection shutdown feature.

The KTS1681A is available in a RoHS and Green compliant 12-Bump 1.70mm x 1.21mm x 0.62mm WLCSP.


  • Wide Input voltage range: 2.3V to 28V
  • Up to 4A Continuous current capability
  • Integrated 28mΩ (typ) N-Channel MOSFET
  • Wide Overvoltage threshold range
    • Fixed internal: 5.95V
    • Adjustable: 4V to 22V
  • Fast OVP response time: 0.1µs (typ.)
  • Internal 15ms Startup Debounce
  • Integrated Surge Protection up to 100V
  • Low Quiescent Current: 70µA (typ.)
  • Thermal Shutdown and Short Circuit Protection
  • Compliance to IEC61000-4-2 (Level 4)
    • Contact: ±8kV
    • Air Gap: ±15kV
  • ESD Protection
    • Human Body Model: ±2kV
  • Pb-free Package: 12-Bump WLCSP
  • RoHS and Green Compliant
  • -40°C to +85°C Temperature Range


  • Smartphones
  • Tablet
  • Mobile Internet Devices
  • Peripherals

Packaging Information

Package Dimensions Bumps Package Code
WLCSP34-12 1.70mm x 1.21mm x 0.62mm 12 UZ


Vin (min) Vin (max) ON Resistance Max Current (A) OVP Trip Point
2.3V 28V 28mΩ 4.5A 5.95V

Technical Documentation

Description Documents Type
Package Outline DrawingWLCSP34-12 UZ PODPDF


Part Number Marking Operating Temperature Package
Purchase Options
Buy from Digi-Key
Buy from Mouser