The A4988 is a complete microstep motor driver with a built-in converter for easy operation. It operates bipolar stepper motors in full, half, 1/4, 1/8, and 1/16 step modes with output drive performance up to 35 V and ±2 A. The A4988 includes a fixed shutdown time current regulator that operates in slow or hybrid attenuation mode.
The converter is key to the ease of implementation of the A4988. A pulse is simply entered into the "stepper" input to drive the motor to produce microsteps. No phase sequence tables, high-frequency control lines, or complex interface programming are required. The A4988 interface is ideal for applications where complex microprocessors are unavailable or overloaded.
When microstepping is running, the chopper control within the A4988 automatically selects the current decay mode (slow or mixed). In hybrid attenuation mode, the device is initially set to degrade rapidly for partial fixed downtime and then slowly decay for the remainder of downtime. The hybrid attenuation current control solution reduces the audible motor noise, increases step accuracy, and reduces power consumption.
An internal synchronous rectification control circuit is provided to improve power consumption during pulse-width modulation (PWM) operation. Internal circuit protection includes thermal shutdown with hysteresis, undervoltage lockout (UVLO), and cross-current protection. No special power-up sequencing is required.
The A4988 is available in a surface-mount QFN package (ES) with dimensions of 5 mm × 5 mm, a nominal overall package height of 0.90 mm, and an exposed heat sink for enhanced thermal functionality. The package is a lead-free package (suffix –T) with a 100% matte tin plated pin frame.
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低 RDS (On) 输出
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自动电流衰减模式检测/选择
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混合与慢电流衰减模式
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对低功率耗散同步整流
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内部 UVLO
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交叉电流保护
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3.3 及 5 V 兼容逻辑电源
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过热关机电路
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接地短路保护
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加载短路保护
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五个可选的步进模式：全、 1/2、1/4、1/8 及 1/16