A1172
Micropower Ultra-Sensitive Hall-Effect Switch

Features                               

• Micropower operation
• Operation with either north or south pole — no magnetic orientation required during assembly
• 1.65 to 3.5 V battery operation
• Chopper stabilization
  • Superior temperature stability
  • Extremely low switchpoint drift
  • Insensitive to physical stress
• Solid state reliability
• Small size: WLCSP (≈ 1 mm × 1 mm × 0.5 mm)
• Complementary, push-pull outputs eliminate need for pull-up resistor

Description

The A1172 is an ultra-sensitive, pole-independent Hall-effect switch with a latched digital output. It features operation at low supply currents and voltages, making it ideal for battery-operated electronics. The 1.65 to 3.5 V operating supply voltage and unique clocking algorithm reduce the average operating power requirements to less than 15 µW with a 2.75 V supply.

The A1172 has two push-pull output structures. Omnipolar activation for the output function is available on each output structure. As such, either a north or south pole of sufficient strength turns the available outputs off or on. The A1172 contains two complementary outputs. Therefore, for a fixed magnetic field, one output will be in a high voltage state and one output will be in a low voltage state.

Improved stability is made possible through dynamic offset cancellation using chopper stabilization, which reduces the residual offset voltage normally caused by device overmolding, temperature dependencies, and thermal stress. This device includes, on a single silicon chip, a Hall-voltage generator, a smallsignal amplifier, chopper stabilization, a latch, and a MOSFET output.

The A1172 device offers magnetically optimized solutions, suitable for most applications. The wafer level chip scale package (WLCSP) is approximately only 1 mm by 1 mm by 0.5 mm. This package is smaller than most plastic packages and reduces the printed circuit board area consumed by micropower Hall-effect switches.

Functional Block Diagram