A1304 Linear Hall-Effect Sensor IC with Analog Output, Available in a Miniature, Low Profile Surface Mount Package FEATURES AND BENEFITS • • • • • • • • • 3.3 V supply operation Allegro factory programmed offset and sensitivity Miniature package High bandwidth, low noise analog output High speed chopping scheme minimizes QVO drift across operating temperature range Temperature-stable quiescent voltage output and sensitivity Precise recoverability after temperature cycling Wide ambient temperature range: –40°C to 85°C Immune to mechanical stress Package: 3-Pin Surface Mount SOT23-W (suffix LH) New applications for linear output Hall effect sensors require medium accuracy and smaller package size. The Allegro A1304 linear Hall effect sensor IC has been designed specifically to achieve both goals. This temperature-stable device is available in a miniature surface mount package (SOT23-W). This ratiometric Hall effect sensor provides a voltage output that is proportional to the applied magnetic field and features a quiescent voltage output of 50% of the supply voltage. Each BiCMOS monolithic circuit integrates a Hall element, offset and sensitivity trim circuitry to correct for the variation in the Hall element, a small-signal high-gain amplifier, and a proprietary dynamic offset cancellation technique. The A1304 sensor IC is available in a 3-pin surface mount SOT-23W style package (LH suffix). The package is lead (Pb) free, with 100% matte tin leadframe plating. Approximate footprint Tuned Filter Dynamic Offset Cancellation Trim Control GND Functional Block Diagram

Linear Hall-Effect Sensor IC with Analog Output, Available in a Miniature, Low Profile Surface Mount PackageSelection Guide Part Number ‘Contact Allegro™ for additional packing options 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com

Linear Hall-Effect Sensor IC with Analog Output, Available in a Miniature, Low Profile Surface Mount PackageSPECIFICATIONSAbsolute Maximum Ratings Characteristic Thermal Characteristics may require derating at maximum conditions, see application information 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com

Linear Hall-Effect Sensor IC with Analog Output, Available in a Miniature, Low Profile Surface Mount PackageOPERATING CHARACTERISTICS: valid across TA, CBypASS = 0.1 pF, Vcc = 3.3 V unless otherwise noted Characteristic 11 gauss (G) is exactly equal to 0.1 millitesla (mT). 2See Characteristic Definitions section. 3Based on design simulations and/or characterization data. Not tested at Allegro end-of-line. 4Sensitivity drift through the life of the part, ASensLIFE , can have a typical error value ±3% in addition to package hysteresis effects. Allegro Microsystems, LLC 115 Northeast Cutoff Worcester,...

Linear Hall-Effect Sensor IC with Analog Output, Available in a Miniature, Low Profile Surface Mount Package CHARACTERISTIC DEFINITIONS Power On Time When the supply is ramped to its operating voltage, the device output requires a finite time to react to an input magnetic field. Power On Time, tPO , is defined as the time it takes for the output voltage to begin responding to an applied magnetic field after the power supply has reached its minimum specified operating voltage, VCC(min), as shown in Figure 1. VOUT(B+) – VOUT(B–) where B+ is the magnetic flux density in a positive field (south polarity)...

Linear Hall-Effect Sensor IC with Analog Output, Available in a Miniature, Low Profile Surface Mount Package and Bx are positive and negative magnetic fields, with respect to the quiescent voltage output, such that |B(+)(2)| > |B(+)(1)| and |B(–)(2)| > |B(–)(1)| The effective linearity error is: LinERR = max(|LinERR+| , |LinERR– |) The saturation of the output at VSAT(HIGH) and VSAT(LOW) will limit the operating magnetic range of the applied field in which the device provides a linear output. The maximum positive and negative applied magnetic fields in the operating range can be calculated: BMAX(+)...

Linear Hall-Effect Sensor IC with Analog Output, Available in a Miniature, Low Profile Surface Mount Package Undervoltage Lockout The A1304 provides an undervoltage lockout feature which ensures that the device outputs a VOUT signal only when VCC is above certain thresholds . The undervoltage lockout feature provides a hysteresis of operation to eliminate indeterminate output states. The output of the A1304 is held low (GND) until VCC exceeds the VCC rising UVLO reset threshold. After that , the device VOUT output is enabled, providing a ratiometric output voltage that is proportional to the...

Linear Hall-Effect Sensor IC with Analog Output, Available in a Miniature, Low Profile Surface Mount Package Figure 5: Typical Application Circuit Chopper Stabilization Technique When using Hall-effect technology, a limiting factor for switchpoint accuracy is the small signal voltage developed across the Hall element. This voltage is disproportionally small relative to the offset that can be produced at the output of the Hall sensor IC. This makes it difficult to process the signal while maintaining an accurate, reliable output over the specified operating temperature and voltage ranges. Chopper...

Linear Hall-Effect Sensor IC with Analog Output, Available in a Miniature, Low Profile Surface Mount Package Package Outline Diagram For Reference Only – Not for Tooling Use (Reference DWG-2840) Dimensions in millimeters – NOT TO SCALE Dimensions exclusive of mold flash, gate burrs, and dambar protrusions Exact case and lead configuration at supplier discretion within limits shown PCB Layout Reference View Branded Face Standard Branding Reference View N = Last three digits of device part number A Active Area Depth, 0.28 mm B Reference land pattern layout All pads a minimum of 0.20 mm from all adjacent...