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Allegro MicroSystems A3966SLB
- Part No.:
- A3966SLB
- Manufacturer:
- Allegro MicroSystems
- Category:
- Motor Drivers, Controllers
- Package:
- 16-PowerSOIC (0.295", 7.50mm Width)
- Datasheet:
-
A3966SLB.pdf
- Description:
- IC MTRDRV BIPLR 4.75-5.5V 16SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,009
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Product details
Overview
A3966SLB from Allegro MicroSystems is a dual full-bridge PWM motor driver IC designed to control both windings of a two-phase bipolar stepper motor, delivering ±650 mA continuous output current per bridge at up to 30 V load supply voltage, with internal fixed-frequency PWM current regulation and Satlington® sink drivers for low saturation voltage and high peak-current capability in industrial motion control systems.
For engineers reviewing the A3966SLB datasheet, A3966SLB pinout, A3966SLB application, or A3966SLB equivalent, key selection considerations include its 16-pin SOICW (LB) package, user-configurable RC-timed PWM frequency (25.4 kHz typical), blanking-window-enabled current-sense stability, thermal shutdown with 15°C hysteresis, and integrated ground-clamp/flyback diodes eliminating external protection components.
Technical Context
The A3966SLB implements two independent full-bridge outputs with phase- and enable-controlled bidirectional current flow per winding. Each bridge uses a fixed-frequency PWM current-control loop with trip threshold set by VREF/(4×RS) + ISO (18 mA typical), where blanking time (1.3 µs nominal) is derived from CT = 680 pF and oscillator frequency is governed by RTCT network (56 kΩ/680 pF yields 25.4 kHz).
Its Satlington® sink drivers achieve 0.3–0.7 V saturation voltage at +400/+650 mA while maintaining Darlington-level peak current capability; crossover-current protection enforces ~1 µs dead time during PHASE transitions, and UVLO disables operation below 4.1 V VCC to prevent erratic logic behavior.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current | ±650 mA continuous per bridge - supports NEMA 11–14 stepper motors without external heatsinking at TA ≤ 85°C |
| Load Supply Voltage | 30 V max - enables direct interface with 24 V industrial power rails |
| PWM Frequency | 25.4 kHz typical (RT=56 kΩ, CT=680 pF) - balances ripple current reduction against switching loss and EMI |
| Saturation Voltage (Sink) | 0.3 V at +400 mA, 0.7 V at +650 mA - minimizes conduction loss and die temperature rise |
| Thermal Shutdown | 165°C junction activation with 15°C hysteresis - provides self-recovery after transient overloads |
| Logic Supply Range | 4.75–5.5 V - compatible with standard 5 V microcontroller I/O without level shifting |
| Current Sense Offset | 18 mA typical - must be included in RS calculation to achieve accurate ITRIP = VREF/(4×RS) + 18 mA |
Pinout & Package
Package: 16-pin SOICW (suffix LB), with pins 4 and 13 internally fused to the exposed die pad for enhanced thermal dissipation; RoHS-compliant, 100% matte tin leadframe plating.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| OUT1A, OUT1B | Bridge 1 output terminals | Drive motor winding 1; polarity determined by PHASE1; capable of ±650 mA continuous |
| OUT2A, OUT2B | Bridge 2 output terminals | Drive motor winding 2; polarity determined by PHASE2; independent current control |
| PHASE1, PHASE2 | Direction control inputs | Logic-high sets current flow OUT1A→OUT1B; logic-low reverses direction; includes 1 µs internal blanking |
| ENABLE1, ENABLE2 | Bridge enable/disable inputs | High disables both drivers in respective bridge; fast decay via internal clamp diodes |
| SENSE1, SENSE2 | Current sense inputs | Monitor voltage across external RS resistors; referenced to GROUND; blanked during switching |
| VREF | Reference voltage input | 0–2 V input setting trip threshold; internally divided by 4 to generate comparator reference |
| RC | Oscillator timing node | Connects external RTCT network; sets PWM frequency and blanking window (tblank = 1900×CT) |
| VBB | Motor supply input | 30 V max load supply; requires local 47 µF electrolytic decoupling |
| VCC | Logic supply input | 4.75–5.5 V; powers internal logic, UVLO, and comparators |
| GROUND | Power and signal reference | Common return for VBB, VCC, SENSE, and die pad; pins 4 & 13 tied internally to this node |
Key Features
| Feature | Design Value |
|---|---|
| Satlington® sink drivers | Combines <0.7 V saturation at 650 mA with Darlington-level peak current handling, reducing conduction loss by ~40% vs. standard bipolar drivers |
| User-selectable blanking window | Configured via CT capacitor (e.g., 680 pF → 1.3 µs); prevents false PWM latch reset from diode reverse-recovery spikes |
| Integrated ground-clamp and flyback diodes | Eliminates need for 8 external diodes in H-bridge layout, reducing BOM count and PCB area |
| Crossover-current protection | Enforces ~1 µs dead time between source/sink switching in each bridge, preventing shoot-through current spikes |
| Thermal shutdown with hysteresis | Shuts down at 165°C TJ and resumes only after cooling to ~150°C, enabling automatic recovery from temporary overload |
Applications
| Industrial CNC Positioning | Medical Infusion Pump Actuation |
|---|---|
Use Scenario: Precise open-loop positioning of X/Y stages in desktop CNC mills using NEMA 14 bipolar stepper motors. IC Role / Device Role / Timing Role: Dual full-bridge driver executing microstepping-compatible PHASE/ENABLE sequencing with fixed-frequency PWM current regulation. Use Value: ±650 mA drive capability ensures torque retention at 200–500 pps; integrated clamp diodes reduce stage settling time by enabling fast current decay. |
Use Scenario: Controlled syringe advancement in battery-powered portable infusion pumps requiring silent, low-EMI motor operation. IC Role / Device Role / Timing Role: Bipolar stepper driver implementing low-noise 25 kHz PWM to minimize audible coil whine and EMI-sensitive analog sensor interference. Use Value: RC-tunable PWM frequency allows optimization for acoustic performance; thermal hysteresis prevents nuisance shutdown during extended duty cycles. |
| Automated Laboratory Instrumentation | Printed Circuit Board Assembly Equipment |
Use Scenario: Sample carousel indexing and reagent arm actuation in benchtop analyzers operating continuously at ambient temperatures up to 85°C. IC Role / Device Role / Timing Role: Motor driver providing robust current regulation across temperature with built-in UVLO and thermal protection. Use Value: –20°C to +85°C ambient rating matches lab environmental specs; 30 V VBB supports 24 V DC power architecture with margin. |
Use Scenario: Pick-and-place head motion control in compact SMT placement machines where board space and thermal management are constrained. IC Role / Device Role / Timing Role: Space-efficient dual H-bridge with fused die-pad thermal path (pins 4/13) enabling >1.8 W dissipation in SOICW footprint. Use Value: Satlington® sink drivers cut conduction loss versus MOSFET-based alternatives, reducing localized heating near sensitive vision modules. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual full-bridge motor driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TB6600HG | Higher 4.5 A peak current, but requires external flyback diodes and separate current-sense amplifiers; no integrated blanking or Satlington structure | Better suited for high-torque NEMA 23+ motors; lacks A3966SLB's integrated protection and thermal recovery behavior | Select when higher current and external component flexibility outweigh BOM simplification and thermal autonomy |
| DRV8825 | Microstepping support (1/32 step), but lower 1.5 A max current; uses external MOSFETs and requires gate drivers; no integrated clamp diodes | Preferred for precision microstepping in 3D printers; lacks A3966SLB's fixed-frequency PWM simplicity and industrial temp range | Select when sub-step resolution is critical and system can accommodate external FETs and sensing circuitry |
Compared with TB6600HG and DRV8825, the A3966SLB delivers optimal balance of integration (clamps, blanking, thermal hysteresis), industrial temperature compliance (–20°C to +85°C), and predictable fixed-frequency current regulation-making it ideal for cost-sensitive, space-constrained motion systems where reliability and design simplicity are prioritized over microstepping or ultra-high current.
Availability
A3966SLB is available at Aetrix Electronics and suitable for industrial CNC positioning, medical infusion pump actuation, automated laboratory instrumentation, and printed circuit board assembly equipment requiring stable component supply and long-term lifecycle assurance.
Supply support for A3966SLB 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 and manufacturer of high-performance magnetic sensors and power ICs, specializing in motion control, energy-efficient power conversion, and ruggedized automotive and industrial semiconductor solutions.
The A3966SLB belongs to Allegro's bipolar stepper motor driver product line, engineered specifically for reliable, integrated motion control in space- and thermal-constrained industrial and medical equipment where simplicity, protection, and consistent current regulation are essential.
FAQ
What is the maximum continuous output current per bridge for the A3966SLB?
The A3966SLB supports ±650 mA continuous output current per full-bridge under conditions of TA ≤ 85°C, adequate heat sinking, and proper PCB layout. Peak current capability reaches ±750 mA, but sustained operation above 650 mA requires derating based on ambient temperature and thermal resistance. The A3966SLB's Satlington® sink drivers help maintain this rating with low saturation voltage even at full load.
How does the A3966SLB implement current regulation without an external controller?
The A3966SLB uses an internal fixed-frequency PWM current-control circuit that compares sensed winding current (via external RS resistors) against a trip threshold derived from VREF. When current reaches ITRIP = VREF/(4×RS) + 18 mA, the source driver turns off; current recirculates through the sink driver and internal clamp diode until the oscillator resets the latch. This fully autonomous loop eliminates the need for external microcontroller-based current control in the A3966SLB.
Can the A3966SLB operate with a 24 V motor supply and 5 V logic supply simultaneously?
Yes, the A3966SLB is explicitly rated for simultaneous operation with VBB = 24 V (within its 30 V absolute max) and VCC = 5 V (within its 4.75–5.5 V operating range). Its internal UVLO circuit ensures clean startup only when VCC exceeds 4.1 V, and the logic inputs (PHASE/ENABLE) are TTL/CMOS-compatible at 5 V levels. Decoupling VBB with a 47 µF capacitor near the A3966SLB pins is required for stable operation.
What is the purpose of the RC pin on the A3966SLB, and how is it configured?
The RC pin on the A3966SLB connects to an external resistor (RT) and capacitor (CT) network that sets both the internal PWM oscillator frequency and the current-sense comparator blanking window. With RT = 56 kΩ and CT = 680 pF, the A3966SLB achieves 25.4 kHz PWM frequency and 1.3 µs blanking time. The blanking window prevents false triggering during switching transients, and the oscillator equation fosc ≈ 1/(RT×CT + tblank) ensures predictable timing behavior in the A3966SLB.
Does the A3966SLB include protection features for overtemperature or undervoltage conditions?
Yes, the A3966SLB integrates thermal shutdown with activation at 165°C junction temperature and 15°C hysteresis for automatic recovery, plus UVLO that disables all outputs if VCC drops below 4.1 V. It also includes crossover-current protection (~1 µs dead time), internal ground-clamp and flyback diodes, and output short-circuit detection via current-sense comparator limits. These protections operate autonomously without external circuitry in the A3966SLB.
A3966SLB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Allegro MicroSystems
- Series:
- -
- Package/Case:
- 16-PowerSOIC (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:
- Parallel
- Technology:
- Bipolar
- Step Resolution:
- -
- Applications:
- General Purpose
- Current - Output:
- 650mA
- Voltage - Supply:
- 4.75V ~ 5.5V
- Voltage - Load:
- 4.75V ~ 30V
- Operating Temperature:
- -20°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-SOIC
A3966SLB FAQ
1.How can I place an order for A3966SLB through Aetrix?
Please submit a Request for Quotation (RFQ) for A3966SLB 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 A3966SLB reliable?
The price and inventory of A3966SLB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for A3966SLB is usually 5 days.
3.What payment methods are accepted for A3966SLB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for A3966SLB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for A3966SLB?
A3966SLB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your A3966SLB 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 A3966SLB?
For technical support, including A3966SLB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your A3966SLB requirements.
6.How does Aetrix verify that A3966SLB is sourced from the original manufacturer or authorized distributors?
All A3966SLB 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 A3966SLB meets industry standards.
7.What is the process for return or replacement of A3966SLB?
All A3966SLB units undergo pre-shipment inspection (PSI). If there is an issue with A3966SLB, 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 A3966SLB part is unused and in its original packaging.
Return procedure for A3966SLB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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