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Allegro MicroSystems A3949SLPTR
- Part No.:
- A3949SLPTR
- Manufacturer:
- Allegro MicroSystems
- Category:
- Motor Drivers, Controllers
- Package:
- 16-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
A3949SLPTR.pdf
- Description:
- IC MOTOR DRIVER 8V-36V 16TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,480
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Product details
Overview
A3949SLPTR from Allegro MicroSystems is a discontinued DMOS full-bridge motor driver IC designed for PWM-controlled DC motors, delivering ±2.8 A peak output current at up to 36 V supply voltage, with PHASE/ENABLE control interface and internal synchronous rectification for reduced power dissipation in industrial actuators and automotive seat/mirror systems.
For engineers reviewing the A3949SLPTR datasheet, A3949SLPTR pinout, A3949SLPTR application, or A3949SLPTR equivalent, key selection considerations include its LB-package thermal resistance (52 °C/W), sleep-mode quiescent current (≤10 μA), UVLO threshold (6 V), crossover delay (500 ns), and internal charge pump architecture requiring CP1/CP2/VCP decoupling.
Technical Context
The A3949SLPTR implements a four-switch DMOS H-bridge with independent source/sink gate drive, using an internal charge pump (CP1/CP2) to generate VCP > VBB for high-side NMOS control and a dedicated VREG regulator for low-side gate drive. It supports forward/reverse/brake/fast-decay SR modes via MODE, PHASE, ENABLE, and SLEEP logic inputs.
Protection includes thermal shutdown at 170 °C with 15 °C hysteresis, VBB and VCP undervoltage lockout (UVLO), and crossover current prevention with 500 ns delay. Synchronous rectification reduces conduction losses during PWM off-time, and sleep mode disables charge pump and VREG to achieve ≤10 μA standby current.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Peak Output Current | ±2.8 A - supports medium-power DC motors without external current sensing |
| Supply Voltage Range | 8–36 V - compatible with 12 V and 24 V industrial and automotive battery rails |
| RDS(ON) (Sink, 25°C) | 0.3–0.43 Ω - limits I²R loss to <1.2 W per switch at 2.8 A |
| RDS(ON) (Source, 25°C) | 0.4–0.48 Ω - enables efficient high-side switching without external bootstrap circuitry |
| UVLO Threshold | 6 V rising - prevents erratic operation during brown-out or cold-cranking conditions |
| Thermal Shutdown | 170 °C junction - protects against sustained overload or inadequate heatsinking |
| Sleep Current | ≤10 μA - extends battery life in portable or always-on motor control applications |
Pinout & Package
The A3949SLPTR is supplied in a 16-pin SOICW package with copper batwing tab (suffix LB), lead-free with 100% matte tin leadframes, JEDEC MS-013 AA compliant, and internally fused pins 4 (SLEEP) and 13 (VCP).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 15 | N/C | No internal connection; must be left unconnected |
| 2 | MODE | Selects slow/fast decay braking mode; determines synchronous rectification behavior |
| 3, 12 | GND | Power ground return path for load current and logic; requires low-impedance PCB plane |
| 4 | SLEEP | Active-high logic input; disables charge pump, VREG, and outputs to reduce quiescent current |
| 5 | ENABLE | Active-high PWM enable; sets bridge to Hi-Z when low, enabling fast decay or brake states |
| 6, 9 | OUTA / OUTB | H-bridge output terminals; connect directly to motor terminals with minimal trace inductance |
| 7 | SENSE | Current-sense return path; used with external sense resistor for overcurrent protection |
| 8 | VBB | Main motor supply input; requires ≥100 μF bulk capacitance and local 0.1 μF ceramic |
| 10, 11 | CP1 / CP2 | Charge pump oscillator nodes; require 0.1 μF ceramic capacitor between them for gate drive voltage generation |
| 13 | VCP | Charge pump reservoir; monitored for UVLO; requires 0.1 μF ceramic to VBB |
| 14 | VREG | Low-side gate regulator output; requires 0.22 μF ceramic decoupling to GND |
Key Features
| Feature | Design Value |
|---|---|
| Internal Charge Pump | Eliminates need for external bootstrap components; enables full-NMOS H-bridge with single supply |
| Synchronous Rectification | Reduces power dissipation by replacing freewheeling diode conduction with low-RDS(ON) MOSFET conduction |
| Integrated UVLO & Thermal Protection | Prevents latch-up and damage during supply sag or overheating without external monitoring circuitry |
| Sleep Mode Control | Reduces system standby power by disabling gate drivers, charge pump, and VREG while retaining logic state |
| Fast Crossover Delay | 500 ns dead-time minimizes shoot-through risk while supporting high-frequency PWM (>20 kHz) |
Applications
| Automotive Seat Actuators | Industrial Linear Actuators |
|---|---|
Use Scenario: Bidirectional positioning of powered vehicle seats using 12 V DC motors under EMI-constrained cabin environments. IC Role / Device Role / Timing Role: Full-bridge motor driver providing PHASE/ENABLE-controlled direction and PWM speed regulation with integrated protection. Use Value: Internal synchronous rectification cuts heat generation by ~30% vs. diode-based freewheeling, reducing heatsink requirements in confined space. | Use Scenario: Precision extension/retraction of factory automation linear stages driven by 24 V brushed DC motors. IC Role / Device Role / Timing Role: Motor interface IC executing fast-decay braking and slow-decay coasting via MODE/ENABLE timing coordination. Use Value: 500 ns crossover delay ensures robust shoot-through immunity at 25 kHz PWM, enabling smooth velocity profiling without audible noise. |
| Medical Infusion Pumps | Robotics Joint Controllers |
Use Scenario: Low-noise, low-power motor control in battery-operated portable infusion devices requiring silent operation and long runtime. IC Role / Device Role / Timing Role: Sleep-enabled motor driver managing micro-stepped peristaltic pump actuation with precise current limiting. Use Value: ≤10 μA sleep current extends single-charge battery life beyond 72 hours, meeting IEC 60601 standby duration requirements. | Use Scenario: Compact joint actuation in collaborative robots where motor drivers must coexist with sensors and controllers on dense PCBs. IC Role / Device Role / Timing Role: Integrated full-bridge driver with thermal shutdown and VCP/VREG fault monitoring for autonomous fault recovery. Use Value: 52 °C/W thermal resistance allows direct mounting on 2-layer PCB without external heatsink, saving board area and assembly cost. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar full-bridge motor driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| A3950SLPTR-T | Successor part with improved RDS(ON) (0.25 Ω sink, 0.32 Ω source), lower sleep current (1 μA), and extended temperature range (–40 to 125 °C) | Supports higher ambient temperatures and longer battery life in portable designs; pin-compatible with A3949SLPTR | Preferred for new designs requiring enhanced efficiency or wider operating range |
| TB6612FNG | Lower peak current (±1.2 A), no internal charge pump (requires external bootstrap), different pinout and control logic (PWM/IN1/IN2) | Better suited for low-power robotics and educational platforms; lacks VCP/VREG monitoring and integrated UVLO on charge pump rail | Consider only if design budget constraints preclude A3950SLPTR-T and motor load remains ≤1 A RMS |
Compared with A3949SLPTR, A3950SLPTR-T offers measurable improvements in thermal performance and power efficiency while maintaining identical LB package and pinout-making it a drop-in upgrade. TB6612FNG provides cost savings but requires redesign of decoupling, protection, and control logic due to architectural differences.
Availability
A3949SLPTR is available at Aetrix Electronics and suitable for legacy system repair, automotive aftermarket replacement, and industrial equipment maintenance requiring stable component supply despite end-of-life status.
Supply support for A3949SLPTR 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 sensing and power IC solutions, headquartered in Worcester, Massachusetts.
The A3949 belongs to Allegro's DMOS full-bridge motor driver product line, engineered for robust, integrated control of brushed DC motors in automotive, industrial, and medical motion systems.
FAQ
Is the A3949SLPTR still in production?
No, the A3949SLPTR is a discontinued product. Allegro MicroSystems ceased production as of June 2, 2014. It is not recommended for new designs, and samples are no longer available. Aetrix Electronics maintains limited legacy stock for repair and maintenance use only.
What is the correct decoupling configuration for the A3949SLPTR?
The A3949SLPTR requires three critical capacitors: a 0.1 μF ceramic between CP1 and CP2, a 0.1 μF ceramic between VCP and VBB, and a 0.22 μF ceramic between VREG and GND. Additionally, a 100 μF bulk capacitor must be placed near VBB to stabilize motor supply transients during PWM switching.
How does the A3949SLPTR implement braking?
The A3949SLPTR supports two braking modes: slow decay (via MODE = 1 and ENABLE = 0) and fast decay with synchronous rectification (via MODE = 0 and ENABLE = 0). In both cases, the H-bridge shorts the motor terminals, dissipating back-EMF energy through internal RDS(ON) paths rather than external diodes.
Can the A3949SLPTR drive a 36 V motor continuously?
Yes, the A3949SLPTR supports continuous operation up to 36 V on VBB, but sustained 36 V operation at ±2.8 A requires adequate PCB copper area (≥2 in² 2-oz copper per side) to maintain junction temperature below 150 °C, given its 52 °C/W RθJA.
What happens during A3949SLPTR thermal shutdown?
When the A3949SLPTR junction temperature reaches 170 °C, internal thermal shutdown disables all outputs until temperature falls by at least 15 °C (hysteresis). During shutdown, VREG and VCP remain active only if their respective supplies are valid; otherwise, full system reset is required after cooling.
A3949SLPTR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Allegro MicroSystems
- Series:
- -
- Package/Case:
- 16-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Motor Type - Stepper:
- -
- Motor Type - AC, DC:
- Brushed DC
- Function:
- Driver - Fully Integrated, Control and Power Stage
- Output Configuration:
- Half Bridge (2)
- Interface:
- Parallel
- Technology:
- DMOS
- Step Resolution:
- -
- Applications:
- General Purpose
- Current - Output:
- 2.8A
- Voltage - Supply:
- 8V ~ 36V
- Voltage - Load:
- 8V ~ 36V
- Operating Temperature:
- -20°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-eTSSOP-EP
A3949SLPTR FAQ
1.How can I place an order for A3949SLPTR through Aetrix?
Please submit a Request for Quotation (RFQ) for A3949SLPTR 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 A3949SLPTR reliable?
The price and inventory of A3949SLPTR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for A3949SLPTR is usually 5 days.
3.What payment methods are accepted for A3949SLPTR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for A3949SLPTR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for A3949SLPTR?
A3949SLPTR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your A3949SLPTR 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 A3949SLPTR?
For technical support, including A3949SLPTR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your A3949SLPTR requirements.
6.How does Aetrix verify that A3949SLPTR is sourced from the original manufacturer or authorized distributors?
All A3949SLPTR 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 A3949SLPTR meets industry standards.
7.What is the process for return or replacement of A3949SLPTR?
All A3949SLPTR units undergo pre-shipment inspection (PSI). If there is an issue with A3949SLPTR, 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 A3949SLPTR part is unused and in its original packaging.
Return procedure for A3949SLPTR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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