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Allegro MicroSystems A3949SLP
- Part No.:
- A3949SLP
- Manufacturer:
- Allegro MicroSystems
- Category:
- Motor Drivers, Controllers
- Package:
- 16-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
A3949SLP.pdf
- Description:
- IC MOTOR DRIVER 8V-36V 16TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,399
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Product details
Overview
A3949SLP from Allegro MicroSystems is a discontinued DMOS full-bridge motor driver IC designed for PWM-controlled bidirectional DC motor operation, 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 loss in industrial actuators and automotive seat/mirror modules.
For engineers reviewing the A3949SLP datasheet, A3949SLP pinout, A3949SLP application, or A3949SLP equivalent, key selection considerations include its 16-pin SOIC-W LB package with fused pins 4 (SLEEP) and 13 (VCP), thermal shutdown at 170°C, UVLO threshold of 6 V, sleep-mode quiescent current ≤10 μA, and RDS(ON) of 0.3–0.48 Ω across temperature.
Technical Context
The A3949SLP implements a four-switch DMOS H-bridge with independent source/sink gate drive architecture, charge-pump-based high-side gate bias (VCP), and regulated low-side gate supply (VREG). Its control logic accepts PHASE/ENABLE/MODE/SLEEP inputs to configure forward/reverse/brake/fast-decay modes with synchronous rectification.
Protection features are hardware-based and fully integrated: undervoltage lockout on VBB and VCP with 250 mV hysteresis, crossover current protection with 500 ns delay, and thermal shutdown with 15°C hysteresis. The device requires external 0.1 μF CP1–CP2 and VCP–VBB capacitors plus 0.22 μF VREG decoupling.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Peak Output Current | ±2.8 A - supports medium-power brushed DC motors up to ~100 W at 24 V with adequate heatsinking |
| Supply Voltage Range | 8–36 V - compatible with 12 V and 24 V automotive and industrial bus systems |
| RDS(ON) (Sink, 25°C) | 0.3–0.43 Ω - limits conduction loss to <1.2 W per switch at 2.8 A |
| Thermal Shutdown Threshold | 170°C - triggers automatic output disable before junction damage occurs |
| Sleep Mode Current | ≤10 μA - enables ultra-low-power standby in battery-operated systems |
| UVLO Enable Threshold | 6 V on VBB - prevents erratic operation during brown-out or cold-cranking conditions |
| Propagation Delay | 100–600 ns - ensures precise PWM timing alignment for closed-loop motor control |
Pinout & Package
The A3949SLP is supplied in a 16-pin SOIC-W package with copper batwing tab (suffix LB), lead-free with 100% matte tin leadframes. Pins 4 (SLEEP) and 13 (VCP) are internally fused.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 15 | N/C | No internal connection; must be left unconnected or tied to GND per layout guidelines |
| 2 | MODE | Selects decay mode (slow/fast) and braking behavior via logic input |
| 3, 12 | GND | Power and signal ground return paths; both must be low-impedance and joined near device |
| 4 | SLEEP | Active-high logic input; forces device into <10 μA standby when low |
| 5 | ENABLE | Active-high PWM enable; disables outputs and halts charge pump when low |
| 6, 9 | OUTA / OUTB | H-bridge output terminals; connect directly to motor terminals with Kelvin sense routing |
| 7 | SENSE | Current-sense return path; used with external shunt for overcurrent detection |
| 8 | VBB | Main motor supply input; requires ≥100 μF bulk capacitance and low-ESR ceramic bypass |
| 10, 11 | CP1 / CP2 | Charge pump oscillator nodes; require 0.1 μF ceramic capacitor between them |
| 13 | VCP | High-side gate 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 |
| 16 | PHASE | Direction control input; sets OUTA/OUTB polarity when ENABLE is high |
Key Features
| Feature | Design Value |
|---|---|
| Synchronous Rectification | Reduces power dissipation by replacing freewheeling diode conduction with active MOSFET conduction during off-time |
| Integrated Charge Pump | Generates gate drive voltage >VBB for high-side DMOS without external boost circuitry |
| Thermal Shutdown with Hysteresis | Auto-recovers only after junction cools by ≥15°C, preventing thermal oscillation during overload |
| Internal UVLO Monitoring | Monitors both VBB and VCP independently; disables outputs if either falls below threshold |
| Fast Decay Braking | Enables rapid motor deceleration by shorting BEMF through both bridge legs with controlled current path |
Applications
| Automotive Power Seats | Industrial Linear Actuators |
|---|---|
Use Scenario: Bidirectional adjustment of seat position using 12–24 V brushed DC motors under variable mechanical load. IC Role / Device Role / Timing Role: Full-bridge motor driver executing PHASE/ENABLE PWM commands from body controller MCU. Use Value: ±2.8 A peak current and thermal shutdown protect against stall-induced overheating during pinch detection events. | Use Scenario: Precision positioning of valves or dampers in HVAC or process control systems with duty-cycle-limited operation. IC Role / Device Role / Timing Role: PWM-controlled H-bridge enabling reversible motion and programmable braking via MODE pin configuration. Use Value: Synchronous rectification reduces I²R losses by ~30% vs. diode-based decay, extending actuator lifetime in thermally constrained enclosures. |
| Medical Bed Adjusters | Robotic End-Effector Grippers |
Use Scenario: Low-noise, reliable height and tilt control in hospital beds powered from 24 V DC supplies with safety-critical fault response. IC Role / Device Role / Timing Role: Motor interface IC providing sleep-mode power reduction and fast-fail protection (UVLO, thermal, crossover). Use Value: 10 μA sleep current enables battery backup operation for emergency repositioning without draining primary power. | Use Scenario: Compact gripper actuation in collaborative robots requiring rapid direction reversal and controlled deceleration. IC Role / Device Role / Timing Role: Bidirectional bridge driver implementing fast-decay SR mode to minimize settling time between grip/release cycles. Use Value: 500 ns crossover delay prevents shoot-through during switching transitions, ensuring robust operation at 20 kHz PWM frequencies. |
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 identical pinout, improved RDS(ON) (0.25 Ω typ), and extended TJ(max) to 165°C | Supports higher continuous current in same PCB footprint; recommended for new designs requiring longer thermal margin | Drop-in replacement per Allegro's transition guidance; verify VCP/VREG capacitor values match revised spec |
| TB6612FNG | 2-channel H-bridge (dual half-bridge); lower peak current (1.2 A), no internal charge pump; requires external gate drivers | Better suited for dual-motor micro-robotics where space and cost outweigh single-motor power needs | Not pin-compatible; requires PCB redesign and additional external components for high-side drive |
Compared with A3949SLP, A3950SLPTR-T offers enhanced thermal performance and lower conduction loss while maintaining full functional and mechanical compatibility; TB6612FNG provides dual independent bridges but lacks integrated high-side drive and requires external biasing, making it suitable only for lower-power distributed motor control architectures.
Availability
A3949SLP is available at Aetrix Electronics and suitable for legacy repair, end-of-life component consolidation, and maintenance of existing automotive seat modules, industrial actuator controllers, and medical bed systems requiring stable component supply despite discontinuation status.
Supply support for A3949SLP 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 Hall-effect sensors, motor drivers, and power ICs, headquartered in Worcester, Massachusetts.
The A3949 belongs to Allegro's DMOS full-bridge motor driver product line, engineered specifically for robust, integrated control of brushed DC motors in automotive comfort systems and industrial motion applications.
FAQ
Is the A3949SLP still in production?
No, the A3949SLP is a discontinued product as confirmed by Allegro MicroSystems' official status update dated June 2, 2014. It is no longer manufactured, and samples are unavailable. Aetrix Electronics maintains limited legacy stock for repair and maintenance use only, not for new design-in.
What is the correct replacement for A3949SLP in new designs?
The A3950SLPTR-T is Allegro's officially recommended substitution for A3949SLP in new designs. It shares the same 16-pin SOIC-W LB package, pinout, and functional interface, while offering improved RDS(ON), higher thermal limit, and updated protection thresholds. Always consult the A3950SLPTR-T datasheet before migration.
Can A3949SLP operate from a 5 V logic supply?
No, the A3949SLP requires VBB ≥ 8 V for normal operation and has logic input thresholds incompatible with 5 V TTL/CMOS: PHASE/ENABLE need ≥2.0 V for logic high, and SLEEP requires ≥2.7 V. It is not 5 V logic-compatible and must be driven from 3.3 V or 5 V level-shifted signals meeting its specified VIN(1) levels.
What external capacitors are mandatory for A3949SLP stability?
The A3949SLP requires three mandatory external 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 on VBB is required to handle motor back-EMF transients and ensure stable charge pump operation.
Does A3949SLP support current sensing?
Yes, the A3949SLP provides a dedicated SENSE pin that serves as the power return path for an external current-sense resistor. When used with a precision shunt in the low-side return path, this enables overcurrent detection and closed-loop current regulation - though the IC itself does not include analog current measurement circuitry.
A3949SLP Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Allegro MicroSystems
- Series:
- -
- Package/Case:
- 16-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Packaging:
- Tube
- 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
A3949SLP FAQ
1.How can I place an order for A3949SLP through Aetrix?
Please submit a Request for Quotation (RFQ) for A3949SLP 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 A3949SLP reliable?
The price and inventory of A3949SLP are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for A3949SLP is usually 5 days.
3.What payment methods are accepted for A3949SLP?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for A3949SLP transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for A3949SLP?
A3949SLP orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your A3949SLP 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 A3949SLP?
For technical support, including A3949SLP datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your A3949SLP requirements.
6.How does Aetrix verify that A3949SLP is sourced from the original manufacturer or authorized distributors?
All A3949SLP 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 A3949SLP meets industry standards.
7.What is the process for return or replacement of A3949SLP?
All A3949SLP units undergo pre-shipment inspection (PSI). If there is an issue with A3949SLP, 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 A3949SLP part is unused and in its original packaging.
Return procedure for A3949SLP:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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