a4983 Allegro MicroSystems, Inc., a4983 Datasheet
a4983
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a4983 Summary of contents
Page 1
... It is designed to operate bipolar stepper motors in full-, half-, quarter-, eighth, and sixteenth-step modes, with an output drive capacity and ±2 A. The A4983 includes a fixed off-time current regulator which has the ability to operate in Slow or Mixed decay modes. ...
Page 2
... DMOS Microstepping Driver with Translator lockout (UVLO), and crossover-current protection. Special power- on sequencing is not required. The A4983 is supplied × × 0.90 nominal surface mount QFN package with exposed thermal pad (suffix ET). The package is lead (Pb) free (suffix –T), with 100% matte tin plated leadframe ...
Page 3
... A4983 VREG VDD Current Regulator REF DAC PWM Latch Blanking Mixed Decay STEP DIR RESET Control Translator MS1 Logic MS2 MS3 PWM Latch ENABLE Blanking Mixed Decay SLEEP DAC V REF DMOS Microstepping Driver with Translator Functional Block Diagram 0.22 F CP1 ROSC Charge ...
Page 4
... A4983 ELECTRICAL CHARACTERISTICS Characteristics Output Drivers Load Supply Voltage Range Logic Supply Voltage Range Output On Resistance Body Diode Forward Voltage Motor Supply Current Logic Supply Current Control Logic Logic Input Voltage Logic Input Current Microstep Select 2 Microstep Select 3 Input Hysteresis Blank Time ...
Page 5
... A4983 THERMAL CHARACTERISTICS may require derating at maximum conditions Characteristic Package Thermal Resistance *In still air. Additional thermal information available on Allegro Web site. DMOS Microstepping Driver with Translator Symbol Test Conditions* R Package ET; 4-layer PCB, based on JEDEC standard θJA Maximum Power Dissipation, P 5.5 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0 ...
Page 6
... A4983 STEP MS1, MS2, MS3, RESET, or DIR STEP minimum, HIGH pulse width STEP minimum, LOW pulse width Setup time, input change to STEP Hold time, input change to STEP Figure 1. Logic Interface Timing Diagram Table 1. Microstep Resolution Truth Table MS1 DMOS Microstepping Driver with Translator ...
Page 7
... A4983 The A4983 is a complete microstepping Device Operation. motor driver with a built-in translator for easy operation with minimal control lines designed to operate bipolar step- per motors in full-, half-, quarter-, and sixteenth-step modes. The currents in each of the two output full-bridges and all of the N-channel DMOS FETs are regulated with fixed off-time PWM (pulse width modulated) control circuitry ...
Page 8
... FETs, current regulator, and charge pump. A logic low on the SLEEP pin puts the A4983 into Sleep mode. A logic high allows normal operation, as well as start-up (at which time the A4983 drives the motor to the Home microstep position) ...
Page 9
... A4983 Current Decay Modes Timing Chart V PHASE + I OUT 0 – I OUT Symbol t off I PEAK OUT DMOS Microstepping Driver with Translator Enlargement A t off PEAK Characteristic Device fixed off-time Maximum output current Slow decay interval Fast decay interval Device output current ...
Page 10
... For optimum electrical and thermal performance, the A4983 must be soldered directly onto the board. On the under- side of the A4983 package is an exposed pad, which provides a path for enhanced thermal dissipation. The thermal pad should be soldered directly to an exposed surface on the PCB. Thermal vias are used to transfer heat to other layers of the PCB ...
Page 11
... A4983 STEP 100.00 70.71 Phase 1 I OUT1A 0.00 Direction = H (%) –70.71 –100.00 100.00 70.71 Phase 2 I OUT2A 0.00 Direction = H (%) –70.71 –100.00 Figure 2. Decay Mode for Full-Step Increments STEP Phase 1 I OUT1A Direction = H (%) –100.00 Phase 2 I OUT2B Direction = H (%) –100.00 Figure 4. Decay Modes for Quarter-Step Increments DMOS Microstepping Driver with Translator ...
Page 12
... A4983 STEP 100.00 92.39 83.15 70.71 55.56 38.27 Phase 1 19.51 I OUT1A 0.00 Direction = H –19.51 (%) –38.27 –55.56 –70.71 –83.15 –92.39 –100.00 100.00 92.39 83.15 70.71 55.56 38.27 Phase 2 19.51 I OUT2B 0.00 Direction = H –19.51 (%) –38.27 –55.56 –70.71 –83.15 –92.39 –100.00 Figure 5. Decay Modes for Eighth-Step Increments DMOS Microstepping Driver with Translator Slow Mixed Mixed Slow ...
Page 13
... A4983 STEP 100.00 95.69 88.19 83.15 77.30 70.71 63.44 55.56 47.14 38.27 29.03 19.51 Phase 1 9.8 I OUT1A 0.00 Direction = H –9.8 (%) –19.51 –29.03 –38.27 –47.14 –55.56 –63.44 –70.71 –77.30 –83.15 –88.19 –95.69 –100.00 100.00 95.69 88.19 83.15 77.30 70.71 63.44 55.56 47.14 38.27 29.03 19.51 Slow Phase 2 9.8 I OUT2B 0.00 Direction = H –9.8 (%) –19.51 –29.03 –38.27 –47.14 –55.56 –63.44 –70.71 –77.30 –83.15 –88.19 –95.69 –100.00 Figure 6. Decay Modes for Sixteenth-Step Increments ...
Page 14
... A4983 Table 2. Step Sequencing Settings Home microstep position at Step Angle 45º; DIR = H Phase 1 Full Half 1/4 1/8 1/16 Current Step Step Step Step Step [% I tripMax ] # # # # # 100. ...
Page 15
... A4983 Terminal List Table Name CP1 CP2 VCP VREG MS1 MS2 MS3 RESET ROSC SLEEP VDD STEP REF GND DIR OUT1B VBB1 SENSE1 OUT1A OUT2A SENSE2 VBB2 OUT2B ENABLE NC PAD *The GND pins must be tied together externally by connecting to the PAD ground plane under the device ...
Page 16
... A4983 ET Package, 28-Pin QFN with Exposed Thermal Pad All dimensions reference, not for tooling use (reference JEDEC MO-220VHHD except contact length and exposed pad length and width) Dimensions in millimeters U.S. Customary dimensions (in.) in brackets, for reference only Dimensions exclusive of mold flash, gate burrs, and dambar protrusions ...