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Selectable Unipolar/Omnipolar Micropower Hall Effect Switch

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The AH1903 is a high sensitivity micropower Omnipolar or Unipolar selectable Hall effect switch IC with internal pull up and pull down capability. Designed for battery powered consumer equipment such as cellular phones and portable PCs to office equipment, home appliances and industrial applications, the average supply current is only 4.3uA at 1.8V. To support portable equipment the AH1903 can operate over the supply range of 1.6V to 3.6V and uses a hibernating clocking system to minimize the power consumption. To minimize PCB space the AH1903 is available in a small low profile X1-DFN1216-4 package.

The user can change the Hall switch function between Unipolar and Omnipolar operation via the Select (SEL) pin. If the SEL pin is open circuit or pulled high the AH1903 operates in Unipolar switch mode detecting only a South pole to the part mark side of the package. If the SEL pin is pulled low the AH1903 functions as a Omnipolar switch detecting either a North or South pole.

The single output is activated with a pole of sufficient magnetic field strength. When the magnetic flux density (B) perpendicular to the package is larger than operate point (Bop), the output will be turned on (pulled low) and held until B is lower than release point (Brp). The output will remain off when there is no magnetic field.

The AH1902 is available in a small low profile X1-DFN1216-4 package


• Unipolar or Omnipolar Operation
       - Operation can be changed by a logic source or fixed via PCB design with no additional components
• Supply Voltage of 1.6V to 3.6V
• High Sensitivity
• Micropower Operation
• Chopper Stabilized Design Provides
      - Superior Temperature Stability
      - Minimal Switch Point Drift
      - Enhanced Immunity to Physical Stress
• No External Pull-up Resistors Required
• Good RF Noise Immunity
• -40°C to +85°C Operating Temperature
• High ESD capability of 8kV (Human Body Model)
• Small Low Profile X1-DFN1216-4 package


• Open and Close Detect for Flip/slide Cellular Phones
• Smart Cover or Dock Detect for Cellular Phones, Tablet PCs and e-Reders
• Cover or Display Switch in Portable PCs (eg Ultrabook)
• Digital Still, Video Cameras and Handheld Gaming Consoles
• Door, Lids and Tray Position Switches
• Level, Proximity and Position Switches
• Contact-Less Switches in Home Appliances  and Industrial Applications

Product Specifications

Product Parameters

Compliance(Only Automotive supports PPAP) Standard
AEC Qualified No
Type Unipolar/Omnipolar
Outputs Single
Output Type Push-Pull
Active Output State (B > Bop) Low
Inactive Output State (B < Brp) High
Key Feature Unipolar/Omnipolar
Operating Voltage (V) 1.6 to 3.6
Average Supply Current (mA) 0.0043
Min Operating Point Bop (Bops +ve/ Bopn -ve) (Gauss) 21
Typ Operating Point Bop (Bops +ve/ Bopn -ve) (Gauss) 33
Max Operating Point Bop (Bops +ve/ Bopn -ve) (Gauss) 48
Min Release Point Brp (Brps +ve/ Brpn -ve) (Gauss) 9
Typ Release Point Brp (Brps +ve/ Brpn -ve) (Gauss) 23
Max Release Point Brp (Brps +ve/ Brpn -ve) (Gauss) 38
Operating Ambient Temperature (°C) -40 to 85

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Technical Documents

Recommended Soldering Techniques


Product Change Notices (PCNs)

A PCN may only apply to specific orderable part numbers in this datasheet. Please refer to the corresponding PCN to see the exact orderable part number(s) affected.

PCN # Issue Date Implementation Date Subject
PCN-2512 2021-04-16 2021-07-16 Qualified Additional Assembly & Test (A/T) Site