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Allegro MicroSystems A3982SLB
- Part No.:
- A3982SLB
- Manufacturer:
- Allegro MicroSystems
- Category:
- Motor Drivers, Controllers
- Package:
- 24-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
A3982SLB.pdf
- Description:
- IC MTR DRV BIPOLAR 3-5.5V 24SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:4,208
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Product details
Overview
A3982SLB from Allegro MicroSystems is a DMOS bipolar stepper motor driver IC with integrated translator, designed for full- and half-step excitation of up to ±2 A per phase at 35 V supply, featuring automatic mixed/slow decay mode selection, synchronous rectification, and internal charge pump for high-side gate drive.
For engineers reviewing the A3982SLB datasheet, A3982SLB pinout, A3982SLB application, or A3982SLB equivalent, this device is selected for embedded motion control where microprocessor resources are constrained, precise current regulation is required, and thermal performance in wide-body SOIC packaging matters.
Technical Context
The A3982SLB implements fixed off-time PWM current regulation per bridge using external sense resistors (RS1/RS2) and a programmable VREF input, with trip current calculated as ITripMAX = VREF / (8 × RS). Its translator interprets STEP/DIR/MS1 inputs to sequence DAC outputs and set winding polarity without external phase tables.
Decay mode is dynamically selected per step: slow decay for increasing current demand and mixed decay (31.25% fast + remainder slow) for decreasing current, minimizing back-EMF distortion and audible noise. Internal charge pump (CP1/CP2/VCP) enables N-channel high-side DMOS drive above VBB, while VREG supplies sink-side logic.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current | ±2 A per phase - supports NEMA 17–23 stepper motors with sufficient heatsinking |
| Load Supply Voltage | 8–35 V - compatible with 12 V and 24 V industrial DC bus systems |
| RDS(on) | 0.33–0.46 Ω - low conduction loss enabling <1.5 W dissipation per bridge at 1.5 A |
| Fixed Off-Time | 20–40 μs - adjustable via ROSC resistor; default 30 μs when ROSC > 3 V |
| VREF Input Range | 0–4 V - sets maximum current trip level with ±5% error at 70.71% and 100% ITripMAX |
| Logic Supply | 3.0–5.5 V - interoperable with 3.3 V and 5 V microcontrollers without level shifting |
| Thermal Shutdown | 165 °C with 15 °C hysteresis - protects against sustained overload or poor PCB thermal design |
Pinout & Package
Package: 24-pin wide-body SOIC (suffix LB), with internally fused PGND leads (pins 6/7 and 18/19) for enhanced thermal conduction and reduced ground impedance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| OUT1A, OUT1B, OUT2A, OUT2B | DMOS full-bridge outputs | Drive bipolar stepper windings; each pair forms one H-bridge with N-channel DMOS FETs |
| SENSE1, SENSE2 | Current sense inputs | Connect to low-side sense resistors (RS1/RS2); max 0.5 V rating limits sense resistor selection |
| VBB1, VBB2 | Motor power supply inputs | Independent 8–35 V supplies per bridge; decoupling recommended near pins |
| STEP, DIR, MS1, ENABLE, RESET | Digital control inputs | 5 V tolerant; accept standard CMOS levels; no external pull-ups required |
| VDD | Logic supply | 3.0–5.5 V input powering translator, DACs, and logic; separate from motor supply |
| VREG | Internal regulator output | Supplies sink-side gate drivers; requires 0.22 μF ceramic decoupling to PGND |
| VCP, CP1, CP2 | Charge pump terminals | Generate gate voltage > VBB for high-side N-FETs; require 0.1 μF ceramic between CP1–CP2 and VCP–VBB |
| ROSC | Timing resistor connection | Sets fixed off-time (tOFF ≈ ROSC / 825); 25 kΩ yields ~30 μs off-time |
| REF | Current reference input | Analog voltage (0–4 V) setting ITripMAX; determines full-scale winding current |
| PGND (pins 6, 7, 18, 19) | Power ground | Internally fused pairs reduce inductance and improve thermal path to PCB copper |
Key Features
| Feature | Design Value |
|---|---|
| Integrated translator | Eliminates need for external step sequencing logic - single STEP pulse advances motor one step |
| Automatic decay mode selection | Per-step decision between slow and mixed decay reduces current waveform distortion and motor noise |
| Synchronous rectification | Turns on low-RDS(on) FETs during decay instead of body diodes, cutting power loss by >40% vs. asynchronous |
| Internal charge pump | Enables fully N-channel H-bridge topology without external high-side drivers or P-channel devices |
| Comprehensive protection | Includes UVLO (2.7 V enable threshold), thermal shutdown (165 °C), and crossover-current prevention |
Applications
| 3D Printer Motion Control | Industrial CNC Indexing Table |
|---|---|
|
Use Scenario: Precise open-loop positioning of extruder carriage and print bed axes in fused deposition modeling (FDM) printers. IC Role / Device Role / Timing Role: Stepper driver with built-in translator executing full/half-step sequences from MCU STEP/DIR signals. Use Value: Reduces firmware complexity and eliminates external sequencer ICs; ±2 A drive supports high-torque NEMA 17 motors at 24 V. |
Use Scenario: Controlled angular positioning of rotary indexing tables in automated assembly stations. IC Role / Device Role / Timing Role: Bipolar stepper driver regulating phase current via VREF and sense resistors, synchronized to PLC step pulses. Use Value: Mixed decay mode minimizes resonance-induced missed steps at mid-band speeds; fused PGND pins improve thermal stability under continuous duty. |
| Medical Lab Automation Dispenser | ATM Cash Transport Mechanism |
|
Use Scenario: Accurate fluid dispensing using peristaltic or syringe-based actuators driven by microstepping-capable steppers. IC Role / Device Role / Timing Role: Translator-driven stepper controller accepting low-jitter STEP commands from safety-certified motion controller. Use Value: Automatic decay selection maintains waveform fidelity across varying load inertia; VDD 3.3–5.5 V range simplifies interface to isolated control domain. |
Use Scenario: Bidirectional transport of cash cassettes along belt and roller paths in bank-grade ATMs. IC Role / Device Role / Timing Role: Dual-bridge stepper driver managing two independent axis motors with ENABLE-controlled idle power reduction. Use Value: Thermal shutdown (165 °C) and UVLO prevent fault propagation during brownout events; wide SOIC-LB package withstands reflow and long-term vibration. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar stepper motor driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TB6600HG | Higher 4.5 A peak current, but requires external translator and lacks automatic decay mode selection | Used where higher torque is needed and MCU handles sequencing; no VREF-based current scaling | Choose TB6600HG only if ±2 A is insufficient and external logic is available for phase control |
| DRV8825 | Microstepping up to 1/32, but rated for only ±1.75 A and lacks integrated charge pump (requires external bootstrap) | Favored in compact consumer electronics where fine resolution outweighs torque; smaller HTSSOP package | Select DRV8825 when sub-step precision is critical and thermal headroom allows lower current operation |
Compared with TB6600HG and DRV8825, the A3982SLB uniquely combines translator integration, automatic decay adaptation, and robust ±2 A drive in a thermally enhanced SOIC package-making it optimal for industrial motion systems where simplicity, reliability, and thermal margin are prioritized over microstepping granularity or ultra-high peak current.
Availability
A3982SLB is available at Aetrix Electronics and suitable for 3D printer motion control, industrial CNC indexing, and medical lab automation requiring stable component supply, long-lifecycle support, and consistent parametric performance across production batches.
Supply support for A3982SLB includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Allegro MicroSystems is a U.S.-based designer of high-performance magnetic sensing and power ICs, specializing in motion control, current sensing, and motor driver solutions for automotive and industrial markets.
The A3982SLB belongs to Allegro's DMOS stepper driver product line, engineered for cost-sensitive, high-reliability motion systems that require minimal external components and robust thermal behavior in wide-temperature environments.
FAQ
What is the maximum motor supply voltage supported by the A3982SLB?
The A3982SLB supports a load supply voltage (VBB) range of 8 V to 35 V. This allows direct operation from common industrial DC rails such as 12 V and 24 V. Exceeding 35 V risks permanent damage to the DMOS output stages, and operation below 8 V may prevent proper charge pump function and high-side gate drive.
How does the A3982SLB determine whether to use slow or mixed decay mode?
The A3982SLB evaluates the DAC output level change between consecutive steps: if the new DAC value is higher than the previous, it selects slow decay; if lower, it selects mixed decay (31.25% fast decay followed by slow decay). This logic is implemented entirely within the A3982SLB's internal control circuitry and requires no external configuration.
Can the A3982SLB operate without an external ROSC timing resistor?
Yes - if the ROSC pin is tied to a voltage greater than 3 V (e.g., directly to VDD), the A3982SLB defaults to a fixed off-time of 30 μs. However, using an external ROSC resistor (e.g., 25 kΩ for ~30 μs) provides design flexibility to optimize decay timing for specific motor inductance and supply conditions.
What is the purpose of the internally fused PGND pins on the A3982SLB package?
The A3982SLB's LB package fuses PGND pins 6/7 and 18/19 internally to reduce ground loop inductance and improve thermal conduction from the die to the PCB copper. This enhances current handling stability and lowers junction temperature rise during continuous ±2 A operation compared to standard SOIC layouts.
Does the A3982SLB support microstepping beyond half-step resolution?
No - the A3982SLB supports only full-step and half-step modes, controlled by the MS1 input. It does not implement microstepping (e.g., quarter-, eighth-, or sixteenth-step). For finer resolution, designers must select alternatives like the DRV8825 or integrate external indexer logic; the A3982SLB prioritizes simplicity and torque integrity over sub-step granularity.
A3982SLB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Allegro MicroSystems
- Series:
- -
- Package/Case:
- 24-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Motor Type - Stepper:
- Bipolar
- Motor Type - AC, DC:
- -
- Function:
- Driver - Fully Integrated, Control and Power Stage
- Output Configuration:
- Half Bridge (4)
- Interface:
- Logic
- Technology:
- DMOS
- Step Resolution:
- 1, 1/2
- Applications:
- General Purpose
- Current - Output:
- 2A
- Voltage - Supply:
- 3V ~ 5.5V
- Voltage - Load:
- 8V ~ 35V
- Operating Temperature:
- -20°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 24-SOIC
A3982SLB FAQ
1.How can I place an order for A3982SLB through Aetrix?
Please submit a Request for Quotation (RFQ) for A3982SLB on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for A3982SLB reliable?
The price and inventory of A3982SLB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for A3982SLB is usually 5 days.
3.What payment methods are accepted for A3982SLB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for A3982SLB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for A3982SLB?
A3982SLB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your A3982SLB order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for A3982SLB?
For technical support, including A3982SLB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your A3982SLB requirements.
6.How does Aetrix verify that A3982SLB is sourced from the original manufacturer or authorized distributors?
All A3982SLB products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that A3982SLB meets industry standards.
7.What is the process for return or replacement of A3982SLB?
All A3982SLB units undergo pre-shipment inspection (PSI). If there is an issue with A3982SLB, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The A3982SLB part is unused and in its original packaging.
Return procedure for A3982SLB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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