Product Brief HIGH VOLTAGE HALL EFFECT LATCH Description The AH278 is an integrated Hall sensor with output driver designed for electronic commutation of brushless DC motor applications. The device includes an on-chip Hall sensor for magnetic sensing, an amplifier that amplifies the Hall voltage, a Schmitt trigger to provide switching hysteresis for noise rejection and two complementary open-collector drivers for sinking large load current. It also includes an internal band-gap regulator which is used to provide bias voltage for internal circuits and allows a wide operating supply voltage ranges. AH278 Parametric Table Supply Current (mA) 12.5 Output Saturation Voltage (24V, 300mA) (V) 0.25 Hysteresis (Gauss) 80 Output Leakage Current (µA) 0.1 Package TO-94 Placing the device in a variable magnetic field, if the magnetic flux density is larger than threshold BOP, the pin DO will be turned low (on) and pin DOB will be turned high (off). This output state is held until the magnetic flux density reverses and falls below BRP, then causes DO to be turned high (off) and DOB turned low (on). Features Benefits · · · · · · · · · · · · · On-Chip Hall Sensor 4V to 30V Supply Voltage 500mA (avg) Output Sink Current Build in Protection Diode for Reverse Power Connecting -20oC to 85oC Operating Temperature Low Profile TO-94 (SIP-4L) Package Build in Over Temperature Protection Function ESD Rating: 300V(Machine Model) Good High Temperature Performance With Over Temperature Protection (OTP) function Very Low Saturation Voltage Complementary Output Optimization Solution: Higher Current at High Voltage(24V) and Temperature (85oC) Applications Additional Available Materials · · · · · · · · 12V/24V Dual-Coil Brushless DC Motor/Fan Power Supply and Switchboard Communications Facilities Industrial Equipment Feb. 2007 Samples Data Sheet Reliability Report ESD Report BCD Semiconductor Manufacturing Limited Product Brief TWO PHASE HALL EFFECT LATCH WITH FG OUTPUT AH278 Pin Configuration Z4 Package (TO-94) 4 GND 3 2 DOB DO 1 VCC Ordering Information Example Package TO-94 Temperature Range -20 to 85 oC Part Number Marking ID Packing Type AH278Z4-AE1 AH278Z4-E1 Bulk AH278Z4-BE1 AH278Z4-E1 Bulk Detailed information please refer to the relevant datasheet. Sales Office: USA 30920 Huntwood Ave. Hayward, CA 94544, USA Tel : +1-510-324-2988 Fax : +1-510-324-2788 Shanghai 8F, B Zone, 900 Yi Shan Road, Shanghai 200233, China Tel : 86-21-6495 9539 Fax : 86-21-6485 9673 Taiwan 4F, 298-1 Rui Guang Road, Nei-Hu District, Taipei, Taiwan Tel : 886-2-2656-2808 Fax : 886-2-2656-2806 Shenzhen Room E, 5F, Noble Center, No.1006, 3rd Fuzhong Road, Futian District, Shenzhen 518026, China Tel : 86-755-8826 7951 Fax : 86-755-8826 7865 Feb. 2007 BCD Semiconductor Manufacturing Limited