My Inquiry
My Account
Allegro MicroSystems A3949SLBTR-T
- Part No.:
- A3949SLBTR-T
- Manufacturer:
- Allegro MicroSystems
- Category:
- Motor Drivers, Controllers
- Package:
- 16-PowerSOIC (0.295", 7.50mm Width)
- Datasheet:
-
A3949SLBTR-T.pdf
- Description:
- IC MOTOR DRIVER 8V-36V 16SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,639
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
A3949SLBTR-T from Allegro MicroSystems is a 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 loss in industrial actuators and automotive seat/mirror systems.
For engineers reviewing the A3949SLBTR-T datasheet, A3949SLBTR-T pinout, A3949SLBTR-T application, or A3949SLBTR-T equivalent, key selection criteria include thermal shutdown (170°C), UVLO threshold (6 V), sleep-mode quiescent current (≤10 μA), RDS(ON) (0.3–0.68 Ω), and LB-package thermal resistance (52 °C/W).
Technical Context
The A3949SLBTR-T 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). It supports forward/reverse/brake/fast-decay SR modes via MODE, PHASE, and ENABLE logic inputs.
Internal protection includes crossover current detection (500 ns delay), thermal shutdown with 15°C hysteresis, and dual undervoltage lockout on VBB (6 V) and VCP. Sleep mode disables charge pump and VREG to reduce supply current to ≤10 μA.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Peak Output Current | ±2.8 A - supports medium-power DC motors without external heatsinking under typical PCB layout |
| 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 at 2.8 A continuous sink current |
| RDS(ON) (Source, 25°C) | 0.4–0.48 Ω - enables efficient high-side switching without external bootstrap circuitry |
| Thermal Shutdown Threshold | 170°C - provides robust overtemperature protection with 15°C hysteresis for stable recovery |
| Sleep Mode Current | ≤10 μA - allows battery-powered systems to maintain long standby duration |
| UVLO Threshold (VBB) | 6 V with 250 mV hysteresis - prevents erratic operation during brownout or cold-cranking conditions |
Pinout & Package
The A3949SLBTR-T is supplied in a 16-pin SOICW package (LB variant) with internally fused pins 4 (SLEEP) and 13 (VCP), copper batwing thermal tab, and lead-free matte tin leadframes.
| 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; determines synchronous rectification timing |
| 3, 12 | GND | Power ground return path for load current and internal logic; requires low-impedance PCB plane |
| 4 | SLEEP | Active-high logic input; forces device into ultra-low-power state when pulled low |
| 5 | ENABLE | Global PWM enable/disable; high = active, low = outputs Hi-Z regardless of PHASE/MODE |
| 6, 9 | OUTA / OUTB | H-bridge output terminals; drive motor terminals with complementary switching |
| 7 | SENSE | Current-sense return node; connects to shunt resistor for closed-loop current monitoring |
| 8 | VBB | Main motor supply input; decoupled with ≥100 μF bulk capacitor and 0.1 μF ceramic |
| 10, 11 | CP1 / CP2 | Charge pump oscillator nodes; require 0.1 μF ceramic capacitor between them for high-side gate drive |
| 13 | VCP | Charge pump reservoir; monitored for UVLO; requires 0.1 μF ceramic to VBB |
| 14 | VREG | Regulated low-side gate supply; requires 0.22 μF ceramic decoupling to GND |
Key Features
| Feature | Design Value |
|---|---|
| Internal Synchronous Rectification | Reduces power dissipation during PWM off-time by enabling body-diode bypass with controlled MOSFET turn-on |
| Integrated Charge Pump | Eliminates need for external bootstrap diode/capacitor; supports 100% duty cycle high-side drive |
| Thermal Shutdown with Hysteresis | Prevents thermal runaway by disabling outputs at 170°C and re-enabling only after junction cools by ≥15°C |
| Dual UVLO Monitoring | Independent lockout on VBB (<6 V) and VCP ( |
| Fast Crossover Protection | 500 ns dead-time insertion prevents shoot-through during switching transitions |
Applications
| Automotive Power Seats | Industrial Linear Actuators |
|---|---|
Use Scenario: Bidirectional positioning of vehicle seat fore/aft and recline mechanisms using 12 V DC motors. IC Role / Device Role / Timing Role: Full-bridge motor driver executing PHASE/ENABLE PWM commands from MCU; manages braking and slow-decay hold. Use Value: Enables precise position control with <10 μA sleep current for ignition-off retention and thermal shutdown for stall protection. | Use Scenario: Controlled extension/retraction of factory automation linear slides driven by 24 V brushed DC motors. IC Role / Device Role / Timing Role: H-bridge interface translating PLC PWM signals into motor direction/speed; handles dynamic braking during emergency stop. Use Value: Delivers ±2.8 A peak current with integrated VCP/VREG regulation, eliminating external gate drivers and reducing BOM count. |
| Medical Bed Adjusters | Robotic End-Effector Drives |
Use Scenario: Smooth, quiet height and tilt adjustment of hospital beds using low-noise PWM motor control. IC Role / Device Role / Timing Role: Motor driver implementing slow-decay braking to minimize mechanical jerk and audible coil whine. Use Value: Synchronous rectification reduces heat generation in enclosed enclosures; RDS(ON) <0.48 Ω limits temperature rise under continuous 2 A load. | Use Scenario: Compact gripper actuation in collaborative robots requiring reversible torque and fast directional reversal. IC Role / Device Role / Timing Role: Bidirectional bridge driver accepting real-time direction updates via PHASE pin while maintaining PWM speed control. Use Value: Fast propagation delays (<600 ns turn-on) and 500 ns crossover guardband ensure responsive, glitch-free motion transitions. |
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 | Same pinout, identical functional block diagram, but rated for ±3.0 A peak current and improved RDS(ON) (0.25 Ω sink typical) | Supports higher continuous current in thermally constrained layouts; same control interface and protection features | Preferred for new designs requiring margin above ±2.8 A or lower conduction loss |
| TB6612FNG | 2-channel H-bridge, 1.2 A per channel, 13 V max supply, no internal charge pump - requires external bootstrap or dual supply | Lower power class; suited for small robotics or educational platforms, not direct replacement for 36 V/2.8 A loads | Consider only for space-constrained, low-voltage (<13 V), low-current (<1.2 A) applications where cost is primary |
Compared with A3949SLBTR-T, the A3950SLPTR-T offers higher current capability and lower RDS(ON) in identical LB packaging, while the TB6612FNG serves a different power tier entirely - lacking charge pump, UVLO on VCP, and thermal hysteresis - making it unsuitable for direct substitution in 24–36 V industrial or automotive use cases.
Availability
A3949SLBTR-T is available at Aetrix Electronics and suitable for automotive seat modules, industrial linear actuators, and medical bed adjusters requiring stable component supply despite end-of-life status.
Supply support for A3949SLBTR-T 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, LLC 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 product line targets cost-sensitive, thermally demanding DC motor control applications in automotive and industrial environments, emphasizing integrated protection, compact packaging, and simplified system-level design.
FAQ
Is the A3949SLBTR-T still in production?
No, the A3949SLBTR-T is a discontinued product. Allegro MicroSystems ceased production as of June 2, 2014. It is not recommended for new design applications, and samples are no longer available. Aetrix Electronics maintains limited legacy stock with full traceability for existing production continuity.
What is the function of the SLEEP pin on the A3949SLBTR-T?
The SLEEP pin on the A3949SLBTR-T is an active-high logic input that disables internal circuitry-including the charge pump and VREG regulator-reducing supply current to ≤10 μA. A logic low places the A3949SLBTR-T into ultra-low-power sleep mode; a logic high restores normal operation after a 1 ms stabilization delay.
Can the A3949SLBTR-T drive a 36 V motor continuously?
Yes, the A3949SLBTR-T supports continuous operation up to 36 V on VBB, with absolute maximum rating of 38 V for <2 μs transients. However, sustained 36 V operation requires adequate PCB copper area (2 in², 2-oz) to maintain junction temperature below 150°C, given its RDS(ON) and 52 °C/W thermal resistance in the LB package.
What capacitors are required for stable operation of the A3949SLBTR-T?
The A3949SLBTR-T requires three mandatory capacitors: a 0.1 μF ceramic between CP1–CP2 for charge pumping; a 0.1 μF ceramic between VCP–VBB as reservoir; and a 0.22 μF ceramic on VREG–GND for low-side gate supply regulation. A 100 μF bulk capacitor on VBB is also recommended for PWM current transients.
Does the A3949SLBTR-T support fast decay with synchronous rectification?
Yes, the A3949SLBTR-T supports fast decay with synchronous rectification (SR) when MODE = 0 and ENABLE is pulsed. The internal control logic forces outputs to high-impedance near zero-current crossing to prevent reverse current flow, as documented in the Control Logic Table on page 6 of the A3949 datasheet.
A3949SLBTR-T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Allegro MicroSystems
- Series:
- -
- Package/Case:
- 16-PowerSOIC (0.295", 7.50mm Width)
- 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-SOIC
A3949SLBTR-T FAQ
1.How can I place an order for A3949SLBTR-T through Aetrix?
Please submit a Request for Quotation (RFQ) for A3949SLBTR-T 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 A3949SLBTR-T reliable?
The price and inventory of A3949SLBTR-T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for A3949SLBTR-T is usually 5 days.
3.What payment methods are accepted for A3949SLBTR-T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for A3949SLBTR-T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for A3949SLBTR-T?
A3949SLBTR-T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your A3949SLBTR-T 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 A3949SLBTR-T?
For technical support, including A3949SLBTR-T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your A3949SLBTR-T requirements.
6.How does Aetrix verify that A3949SLBTR-T is sourced from the original manufacturer or authorized distributors?
All A3949SLBTR-T 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 A3949SLBTR-T meets industry standards.
7.What is the process for return or replacement of A3949SLBTR-T?
All A3949SLBTR-T units undergo pre-shipment inspection (PSI). If there is an issue with A3949SLBTR-T, 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 A3949SLBTR-T part is unused and in its original packaging.
Return procedure for A3949SLBTR-T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
A3949SLBTR-T Tags
-
DRV2603RUNR
Texas Instruments
-
DRV8837CDSGR
Texas Instruments
-
DRV8837DSGR
Texas Instruments
-
DRV8838DSGR
Texas Instruments
-
DRV8839DSSR
Texas Instruments
-
EMC2301-1-ACZL-TR
Microchip Technology
-
DRV8231ADSGR
Texas Instruments
-
EMC2302-2-AIZL-TR
Microchip Technology
-
DRV8800PWPR
Texas Instruments
-
DRV8835DSSR
Texas Instruments
-
EMC2303-1-KP-TR
Microchip Technology
-
DRV8876PWPR
Texas Instruments
Tech Hub
A practical engineering and sourcing framework covering lifecycle verification, lifetime-buy calculations, replacement qualification, supplier checks and counterfeit-risk controls.
TTL and CMOS logic families differ in thresholds, loading, output drive, power and timing. This engineering guide compares 74HC and 74HCT, calculates noise margins and checks 3.3 V/5 V compatibility.
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
