AK8777B

[AK8777B] AK8777B Hall Effect IC for Pulse Encoders Overview The AK8777B is a Hall effect latch which detects both “vertical” and “horizontal”(perpendicular and parallel to the marking side of the package) magnetic field at the same time. The output OUTA and OUTB are switched according to the vertical and horizontal magnetic fields applied to the device. The AK8777B is for use in the incremental pulse encoders or rotational detection systems. Features o 4.0 to 24V supply voltage operation o Sensitivity (Vertical, Horizontal) : ±1.7mT(Typ.) o Two outputs : OUTA (detects vertical magnetic field), OUTB (detects horizontal magnetic field) o Small package: SOP-6pin o Halogen free MS1465-E-01 1 April 2013 0.1µF CHOPPER_SW LATCH & LOGIC Block Diagram [AK8777B] VDD VSS REGULATOR VREG BIAS HE_DRIVE OSC TIMING LOGIC CHOP_AMP COMP HALL SENSORS Figure 1. Block diagram OUTA OUTB Circuit Configuration Block REGULATOR HALL SENSORS CHOPPER_SW CHOP_AMP COMP BIAS HE_DRIVE OSC TIMING LOGIC LATCH & LOGIC Table 1. Circuit configuration Function Generate internal operating voltage. Two Hall elements fabricated by CMOS process. Perform chopping in order to cancel the offset of Hall sensor. Amplifies two Hall sensor output voltage with summation and subtraction circuit. Hysteresis comparator. Generates bias current to internal circuits. Generates bias current for Hall sensors. Generates operating clock. Generates timing signal for internal circuits. Logical circuits and open drain d...