A3955 Allegro MicroSystems, Inc., A3955 Datasheet
A3955
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A3955 Summary of contents
Page 1
... V CC 29319.41E Description The A3955 is designed to drive one winding of a bipolar stepper motor in a microstepping mode. The outputs are rated for continuous output currents to ±1.5 A and operating voltages Internal pulse width modulated (PWM) current control combined with an internal three-bit nonlinear digital- to-analog converter allows the motor current to be controlled in full-, half-, quarter-, or eighth-step (microstepping) modes ...
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... Internal circuit protection includes thermal shutdown with hysteresis, transient-suppression diodes, and crossover-current protection. Special power-up sequencing is not required. The A3955 is supplied in a choice of two power packages; a 16-pin dual-in-line plastic package with copper heat-sink tabs (suffix ‘B’), Selection Guide Part Number ...
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... A3955 Full-Bridge PWM Microstepping Motor Driver ELECTRICAL CHARACTERISTICS at T (unless otherwise noted.) Characteristic Power Outputs Load Supply Voltage Range Output Leakage Current Output Saturation Voltage (Forward or Reverse Mode) Sense Current Offset Clamp Diode Forward Voltage (Sink or Source) Motor Supply Current (No Load) Table 1 — ...
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... A3955 Full-Bridge PWM Microstepping Motor Driver ELECTRICAL CHARACTERISTICS (continued 5.5 V (unless otherwise noted. ) Characteristic Control Circuitry Logic Supply Voltage Range Reference Voltage Range UVLO Enable Threshold UVLO Hysteresis Logic Supply Current Logic Input Voltage Logic Input Current Mixed-Decay Comparator Trip Points ...
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... A3955 Full-Bridge PWM Microstepping Motor Driver ELECTRICAL CHARACTERISTICS (continued 5.5 V (unless otherwise noted. ) Characteristic Control Circuitry (cont’d) Thermal Shutdown Temp. Thermal Shutdown Hysteresis AC Timing PWM RC Fixed Off-time PWM Turn-Off Time t PWM Turn-On Time PWM Minimum On Time Crossover Dead Time = 25°C, V ...
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... A3955 Full-Bridge PWM Microstepping Motor Driver Note the A3955SB (DIP) and the A3955SLB (SOIC) are electrically identical and share a common terminal number assignment. Terminal Name Description 1 PFD (Percent Fast Decay) The analog input used to set the current-decay mode. 2 REF ( The parallel combination of external resistor R PWM current regulator ...
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... To improve motor performance, especially when using sinusoidal current profi les necessary for microstepping, the A3955 has three distinct current-decay modes: slow decay, fast decay, and mixed decay. The PHASE input controls the direction of PHASE Input. current fl the load (table 1). An internally generated dead time of approximately 1 μ ...
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... A3955 Full-Bridge PWM Microstepping Motor Driver reference value, resulting in increased motor performance in microstepping applications. For a given level of ripple current, slow decay affords the lowest PWM frequency, which reduces heating in the motor and driver IC due to a corresponding decrease in hysteretic core losses and switching losses respectively ...
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... A3955 Full-Bridge PWM Microstepping Motor Driver . If V Mixed Current-Decay Mode and 3.1 V, the device will mixed current-decay mode. Mixed-decay mode allows the user to achieve good current regulation with a minimum amount of ripple current and motor/driver losses by selecting the minimum percentage of fast decay required for their application (see also the Stepper Motor Applications section) ...
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... The output transistors are re-enabled when the junction temperature cools to approximately +150°C. The A3955 is used to Stepper Motor Applications. optimize performance in microstepping/sinusoidal stepper-motor BRIDGE A ...
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... A3955 Full-Bridge PWM Microstepping Motor Driver Full Half Quarter Eighth Step Step Step Step ...
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... A3955 Full-Bridge PWM Microstepping Motor Driver A 100 92.4 83.1 70.7 55.5 38.2 19 19.5 38.2 55.5 70.7 CURRENT IN PER CENT Figure 5 — Current and Displacement Vectors MAXIMUM FULL-STEP FULL STEP B 83.1 92.4 100 Dwg. GK-020-1 Allegro MicroSystems, Inc. 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 12 ...
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... A3955 Full-Bridge PWM Microstepping Motor Driver .005 [1.27] 10. 16X 0.10 C 0.41 1.27 Copyright ©1997-2007, Allegro MicroSystems, Inc. The products described here are manufactured under one or more U.S. patents, including U. S. Patent No. 5,684,427, or U.S. patents pending Allegro MicroSystems, Inc. reserves the right to make, from time to time, such de par tures from the detail spec tions as may be required to per- mit improvements in the per for mance, reliability, or manufacturability of its products ...