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Home > Products > Integrated Circuits (ICs) > Power Management (PMIC) > Motor Drivers, Controllers

Allegro MicroSystems A3953SLBTR

Name: A3953SLBTR
Brand: Allegro MicroSystems
SKU: A3953SLBTR
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: A3953SLBTR

Manufacturer:: Allegro MicroSystems

Category:: Motor Drivers, Controllers

Package:: 16-PowerSOIC (0.295", 7.50mm Width)

Datasheet:: A3953SLBTR.pdf

Description:: IC MTR DRV BIPOLAR 3-5.5V 16SOIC

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Product details

Overview

A3953SLBTR from Allegro MicroSystems is a discontinued 16-pin SOICW full-bridge PWM motor driver IC designed for bidirectional current control of brushed DC and stepper motors. It delivers ±1.3 A continuous output current at up to 50 V load supply, features internal fixed off-time PWM current regulation, thermal shutdown with 165°C trip point and 8°C hysteresis, and supports fast/slow current-decay modes via MODE input - used in industrial motion control and automotive seat/mirror actuators.

For engineers reviewing the A3953SLBTR datasheet, A3953SLBTR pinout, A3953SLBTR application, or A3953SLBTR equivalent, key selection considerations include its SOICW package with internally fused pins, RC-timed off-time configuration (t_OFF ≈ R_T × C_T), brake-mode override behavior, and compatibility with 3.0–5.5 V logic supplies - all critical for legacy motor-control board refresh and obsolescence mitigation.

Technical Context

The A3953SLBTR implements a transconductance-based PWM current-control loop where peak load current I_TRIP ≈ V_REF/R_S – I_SO, with user-settable t_OFF via external R_T/C_T network (e.g., 20.4 μs typ. at 30 kΩ/680 pF). Its dual decay modes are controlled by MODE: slow decay disables only the source driver, enabling recirculation through sink and clamp diodes; fast decay disables both source and sink, forcing energy return to V_BB via flyback paths.

Brake functionality is hardware-asserted via low BRAKE input, overriding ENABLE and PHASE to activate both sinks - enabling dynamic motor braking with optional PWM current limiting when MODE = H. Internal protections include crossover dead time (0.3–3.0 μs), UVLO (2.75 V threshold), and thermal shutdown with hysteresis, eliminating need for external sequencing.

Key Specifications

Parameter	Value and Actual Design Meaning
Continuous Output Current	±1.3 A - maximum sustained bidirectional load current without derating under specified thermal conditions
Load Supply Voltage	50 V max - supports 12 V, 24 V, and 48 V industrial motor rails with margin for inductive kick
Logic Supply Range	3.0–5.5 V - compatible with 3.3 V and 5 V microcontrollers without level-shifting
PWM Fixed Off-Time	18.3–22.5 μs (typ. 20.4 μs) - sets minimum current-regulation cycle duration and ripple magnitude
Thermal Shutdown Threshold	165°C (typ.) with 8°C hysteresis - latches off all drivers until junction cools, preventing thermal runaway
Maximum PWM Frequency	70 kHz - upper limit for internal current-loop operation at full 1.3 A load current
Crossover Dead Time	0.3–3.0 μs - prevents shoot-through during PHASE/MODE transitions by delaying complementary driver turn-on

Pinout & Package

Package: 16-pin SOICW (wide-body) with internally fused pins and exposed thermal tab tied to GROUND - requires no electrical isolation, supports 67°C/W junction-to-ambient thermal resistance on 2-layer PCB with 0.3 in² copper per side.

Pin/Terminal	Circuit Role	Design Meaning
1, 2, 3, 4, 5, 6, 7, 8, 12, 13, 14, 15	Ground (GND)	Twelve dedicated ground terminals - minimize IR drop and improve thermal conduction from die to PCB
9	V_BB	Motor power supply input - connects to bulk capacitor (>47 μF) near device for low-impedance current return
10	RC	RC timing node - sets fixed off-time (t_OFF) and comparator blanking window via external R_T/C_T
11	V_CC	Logic supply input - powers internal logic, reference, and comparators; must be decoupled locally
16	PHASE	Polarity control - selects OUTA/OUTB sourcing/sinking pair to determine motor direction in ENABLE = L mode
16-Pin SOICW Pin 1	ENABLE	Global driver enable - low enables H-bridge; high disables all outputs and enters standby (12–15 mA I_CC)
16-Pin SOICW Pin 11	MODE	Decay mode select - high enables fast decay (both drivers off); low enables slow decay (source only off)
16-Pin SOICW Pin 14	BRAKE	Hardware brake override - low forces both sinks ON and both sources OFF, independent of ENABLE/PHASE
16-Pin SOICW Pin 15	REF	Current-limit reference - sets I_TRIP via external voltage; max bias current ±5 μA affects divider accuracy
16-Pin SOICW Pin 13	SENSE	Current-sense input - compares voltage across external R_S to REF; range 0–0.4 V (3.3 V V_CC) or 0–1.0 V (5 V V_CC)
16-Pin SOICW Pin 4 & 5	OUTA / OUTB	H-bridge outputs - drive motor terminals; each includes integrated clamp diodes rated 1.2–1.6 V forward drop at 1.3 A

Key Features

Feature	Design Value
Internal PWM current control	Eliminates need for external current-sense amplifier and PWM controller - reduces BOM count and layout complexity
Fast/slow current-decay selection	Enables optimization of torque ripple and efficiency: slow decay minimizes switching loss in hold/microstep; fast decay improves current tracking in dynamic loads
Hardware brake override	Provides deterministic, low-latency motor stopping (<1 μs propagation delay) without software intervention or state-machine coordination
Integrated transient-suppression diodes	Clamps inductive flyback energy directly at outputs - removes requirement for four external Schottky diodes in most 24 V applications
Sleep mode (500–800 μA I_CC)	Reduces system standby power in battery-operated devices such as portable medical pumps or smart locks
Thermal shutdown with hysteresis	Prevents thermal cycling during overload - device remains latched off until junction cools by ≥8°C, ensuring stable recovery

Applications

Industrial Actuators	Automotive Comfort Systems
Use Scenario: Precise position control of linear actuators in CNC valve positioning and automated test equipment. IC Role / Device Role / Timing Role: Full-bridge driver executing microstepping waveforms with programmable decay mode to suppress resonance and maintain torque at low speeds. Use Value: Slow-decay mode limits switching losses during hold, extending actuator lifetime; RC-timed off-time ensures consistent current regulation across temperature.	Use Scenario: Bidirectional control of power seat and mirror adjustment motors in passenger vehicles. IC Role / Device Role / Timing Role: H-bridge interface between 3.3 V MCU and 12 V brushed DC motor, implementing hardware brake for immediate stop and thermal protection for fault tolerance. Use Value: Integrated clamp diodes eliminate external components; sleep mode reduces quiescent current below 1 mA during vehicle ignition-off state.
Medical Pumps	Robotics Joint Control
Use Scenario: Constant-current drive for peristaltic pump motors in infusion systems requiring smooth flow and stall detection. IC Role / Device Role / Timing Role: Current-regulated motor driver using REF voltage and SENSE feedback to maintain precise flow rate independent of battery voltage sag. Use Value: ±1.3 A rating supports high-torque pump heads; UVLO (2.75 V) prevents erratic behavior during brownout conditions.	Use Scenario: Torque-controlled joint actuation in collaborative robots using brushed DC motors with current feedback. IC Role / Device Role / Timing Role: Bidirectional PWM driver operating in fast-decay mode to achieve rapid current reversal for responsive joint dynamics. Use Value: 70 kHz max PWM frequency enables high-resolution torque control; crossover dead time prevents shoot-through during direction reversals.

Industrial Actuators

Automotive Comfort Systems

Use Scenario: Precise position control of linear actuators in CNC valve positioning and automated test equipment.

IC Role / Device Role / Timing Role: Full-bridge driver executing microstepping waveforms with programmable decay mode to suppress resonance and maintain torque at low speeds.

Use Value: Slow-decay mode limits switching losses during hold, extending actuator lifetime; RC-timed off-time ensures consistent current regulation across temperature.

Use Scenario: Bidirectional control of power seat and mirror adjustment motors in passenger vehicles.

IC Role / Device Role / Timing Role: H-bridge interface between 3.3 V MCU and 12 V brushed DC motor, implementing hardware brake for immediate stop and thermal protection for fault tolerance.

Use Value: Integrated clamp diodes eliminate external components; sleep mode reduces quiescent current below 1 mA during vehicle ignition-off state.

Medical Pumps

Robotics Joint Control

Use Scenario: Constant-current drive for peristaltic pump motors in infusion systems requiring smooth flow and stall detection.

IC Role / Device Role / Timing Role: Current-regulated motor driver using REF voltage and SENSE feedback to maintain precise flow rate independent of battery voltage sag.

Use Value: ±1.3 A rating supports high-torque pump heads; UVLO (2.75 V) prevents erratic behavior during brownout conditions.

Use Scenario: Torque-controlled joint actuation in collaborative robots using brushed DC motors with current feedback.

IC Role / Device Role / Timing Role: Bidirectional PWM driver operating in fast-decay mode to achieve rapid current reversal for responsive joint dynamics.

Use Value: 70 kHz max PWM frequency enables high-resolution torque control; crossover dead time prevents shoot-through during direction reversals.

Equivalent & Alternatives

The following parts are listed as comparable options for similar full-bridge PWM motor driver applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
A4973	Successor device with higher 3.5 A continuous current, integrated current-sense amplifier, and SPI interface - not pin-compatible; requires PCB redesign.	Supports closed-loop torque control in servo systems; lacks hardware BRAKE override and fixed off-time simplicity.	Select A4973 for new designs requiring higher current or digital diagnostics; retain A3953SLBTR only for legacy repair or exact form-fit replacement.
TB6612FNG	2-channel H-bridge with 1.2 A per channel, 13 V max V_BB, no internal PWM - requires external PWM generation and current sensing.	Targeted at low-voltage robotics; lacks thermal shutdown hysteresis and integrated clamp diodes.	Choose TB6612FNG only if V_BB ≤ 13 V and external control logic is acceptable; unsuitable for 24/48 V industrial use cases.

Compared with A4973 and TB6612FNG, the A3953SLBTR provides unique value in legacy 24–48 V brushed motor systems requiring self-contained PWM current regulation, hardware brake, and robust thermal protection - but demands careful obsolescence planning due to discontinuation status.

Availability

A3953SLBTR is available at Aetrix Electronics and suitable for industrial motion control, automotive comfort systems, and medical pump applications requiring stable component supply despite end-of-life status.

Supply support for A3953SLBTR 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 semiconductor company specializing in high-performance magnetic sensing and power ICs for motion control and energy-efficient systems.

The A3953 belongs to Allegro's legacy full-bridge motor driver product line, engineered for robust bidirectional DC motor control in harsh environments including automotive and industrial settings.

FAQ

Is the A3953SLBTR still in production?

No, the A3953SLBTR was discontinued by Allegro MicroSystems effective January 30, 2012. It is no longer manufactured, and samples are unavailable. Aetrix Electronics maintains limited legacy stock for repair and maintenance of existing systems, with full traceability and documentation support for A3953SLBTR.

What is the difference between A3953SLBTR and A3953SB-T?

The A3953SLBTR and A3953SB-T share identical electrical specifications and pinout assignments but differ in package: A3953SLBTR uses a 16-pin SOICW with internally fused pins and 67°C/W thermal resistance, while A3953SB-T uses a 16-pin DIP with exposed thermal tabs and 43°C/W thermal resistance - making A3953SB-T better suited for high-power, low-airflow environments.

Can the A3953SLBTR be used with 3.3 V logic supplies?

Yes, the A3953SLBTR supports 3.0–5.5 V logic supply (V_CC) and specifies valid operation down to 3.0 V. At 3.3 V, the SENSE input range is 0–0.4 V, and RC timing remains functional with C_T ≥ 680 pF - confirmed in the Electrical Characteristics table for A3953SLBTR.

How does the BRAKE input function on the A3953SLBTR?

When BRAKE is driven low, the A3953SLBTR overrides ENABLE and PHASE to force both sink drivers ON and both source drivers OFF - shorting the motor terminals to ground for dynamic braking. In this mode, current decay is determined by MODE setting: fast decay (MODE = H) applies PWM current limiting; slow decay (MODE = L) disables current control entirely.

What thermal management is required for the A3953SLBTR at full 1.3 A load?

At ±1.3 A continuous current, the A3953SLBTR requires PCB copper area connected to its exposed thermal tab: 0.3 in² of 2-oz copper per side achieves 67°C/W θ_JA. For reliable operation, keep junction temperature below 125°C using the formula T_J ≈ T_TAB + (I_LOAD × 2 × V_F × θ_JT), where θ_JT = 6°C/W and V_F ≈ 1.3 V (sink) per A3953SLBTR datasheet.

A3953SLBTR 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:: Bipolar

Motor Type - AC, DC:: Brushed DC

Function:: Driver - Fully Integrated, Control and Power Stage

Output Configuration:: Half Bridge (2)

Interface:: Parallel

Technology:: Bipolar

Step Resolution:: -

Applications:: General Purpose

Current - Output:: 1.3A

Voltage - Supply:: 3V ~ 5.5V

Voltage - Load:: 3V ~ 50V

Operating Temperature:: -20°C ~ 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 16-SOIC

A3953SLBTR FAQ

1.How can I place an order for A3953SLBTR through Aetrix?

Please submit a Request for Quotation (RFQ) for A3953SLBTR 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 A3953SLBTR reliable?

The price and inventory of A3953SLBTR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for A3953SLBTR is usually 5 days.

3.What payment methods are accepted for A3953SLBTR?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for A3953SLBTR transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for A3953SLBTR?

A3953SLBTR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your A3953SLBTR 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 A3953SLBTR?

For technical support, including A3953SLBTR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your A3953SLBTR requirements.

6.How does Aetrix verify that A3953SLBTR is sourced from the original manufacturer or authorized distributors?

All A3953SLBTR 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 A3953SLBTR meets industry standards.

7.What is the process for return or replacement of A3953SLBTR?

All A3953SLBTR units undergo pre-shipment inspection (PSI). If there is an issue with A3953SLBTR, 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 A3953SLBTR part is unused and in its original packaging.

Return procedure for A3953SLBTR:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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