The A4987 is a dual DMOS full-bridge stepper motor driver with parallel input communication and overcurrent protection. Each full-bridge output is rated at 35 V and ±1 A. The A4987 features a fixed downtime flush width modulation (PWM) current regulator and a 2-position nonlinear DAC (digital-to-analog converter) that allows the stepper motor to be controlled in full, 1/2, and 1/4 steps. PWM current regulators use Allegro's® patented hybrid attenuation mode to reduce audible motor noise, increase step accuracy, and reduce power dissipation.
An internal synchronous rectification control circuit is provided to improve power consumption during pulse-width modulation (PWM) operation.
Provides short-circuit load and ground short-circuit protection for the output, thereby protecting the driver and associated circuitry from thermal damage or burnout. Additional protection features include thermal shutdown with hysteresis, undervoltage lockout (UVLO), and cross-current protection. No special power-up sequencing is required.
The A4987 is available in two packages: a 24-contact QFN (ES) and a 24-pin TSSOP (LP). Both packages come with exposed heat sinks for enhanced thermal performance. The 24-contact ES is available in 4 mm × 4 mm packages with a nominal overall package height of 0.75 mm. The 24-pin LP is a TSSOP package with a 0.65 clearance and an overall package height of ≤1.2 mm. Both packages are lead-free and feature 100% matte tin-plated pin frames.
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低 RDS(开) 输出
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内部混合电流衰减模式
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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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超薄 QFN 和 TSSOP 封装
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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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低电流休眠模式，