The A3966 drives two windings of a two-phase bipolar stepper motor. The device includes two all-electric bridges capable of continuously outputting ±650 mA and operating voltages up to 30 V. Motor winding current can be controlled through internal fixed frequency, pulse-width modulation (PWM), and current control circuitry. The user can set the peak load current limit by selecting the reference voltage and current sense resistor.
Users can set a fixed frequency pulse duration by selecting an external RC timing network. Capacitors in RC timing networks can also be determined by the user, with a blank window that prevents false triggering of PWM current control circuits during switching.
To reduce chip power dissipation, the full-bridge power output has been optimized to accommodate low saturation voltages. The charger driver features Allegro's® patented Satlington® output structure. Satlington outputs combine the low voltage drop of saturated transistors with Darlington's high peak current capacity.
The "phase" input of each bridge controls the polarity of the load current by selecting the appropriate source and pull-in drivers. When the "Enable" input of each bridge is held high, the output driver is disabled. No special power-up sequencing is required. Internal circuit protection includes overheating shutdown due to hysteresis, grounding clamp flyback diode and crossover current protection.
The A3966 is available in a 16-pin plastic SOIC package with two pins connected to the underpad via an internal fuse for enhanced thermal dissipation. These pins are at ground potential and do not require electrical insulation. The device is lead-free and the pin frame is 100% matte tin plated.
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±650 毫安连续输出电流
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30 伏特输出电压额定值
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内部固定频率 PWM 电流控制
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Satlington® 灌电流驱动器
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用户可选择空白窗口
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内部接地钳位和反激二极管
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内部过热关机电路
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交叉电流和欠压锁定 (UVLO) 保护