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

Allegro MicroSystems A3988SJPTR-1-T

Name: A3988SJPTR-1-T
Brand: Allegro MicroSystems
SKU: A3988SJPTR-1-T
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: A3988SJPTR-1-T

Manufacturer:: Allegro MicroSystems

Category:: Motor Drivers, Controllers

Package:: 48-LQFP Exposed Pad

Datasheet:: A3988SJPTR-1-T.pdf

Description:: IC MTR DRV BIPOLAR 3-5.5V 48LQFP

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Product details

Overview

A3988SJPTR-1-T from Allegro MicroSystems is a discontinued 48-pin LQFP quad DMOS full-bridge PWM motor driver rated for 1.2 A per channel and 36 V load supply, featuring fixed 8.1 µs off-time current regulation, mixed-decay mode, and synchronous rectification for bipolar stepper or DC motor control in industrial motion systems.

For engineers reviewing the A3988SJPTR-1-T datasheet, A3988SJPTR-1-T pinout, A3988SJPTR-1-T application, or A3988SJPTR-1-T equivalent, this page delivers verified package mapping (48-pin LQFP), confirmed thermal resistance (23 °C/W), exact pin functions (e.g., PHASE1–PHASE4, VREF1–VREF4, SENSE1–SENSE4), and validated replacement guidance per Allegro's September 2024 discontinuation notice.

Technical Context

The A3988SJPTR-1-T implements four independent N-channel DMOS full-bridges with fixed 8.1 µs off-time PWM current regulation, each controlled by dedicated PHASE/I0/I1 logic inputs and analog VREFx reference voltage. It uses Allegro's patented mixed-decay mode-30.1% fast decay followed by slow decay-to reduce audible noise and improve step accuracy.

Internal charge pump (CP1/CP2/VCP) enables high-side N-MOSFET drive above VBB; synchronous rectification minimizes power dissipation during current decay; protection includes thermal shutdown (155–175 °C), UVLO on VBB (7.3–7.9 V) and VDD (2.65–2.95 V), and crossover-current prevention with 300–1000 ns delay.

Key Specifications

Parameter	Value and Actual Design Meaning
Output rating	1.2 A continuous per bridge (2.8 A pulsed); supports dual stepper or quad DC motor control without external current amplification.
Load voltage range	8–36 V (38 V pulsed); compatible with standard 24 V industrial rails and 32 V stepper supplies.
Fixed off-time	8.1 µs; enables higher PWM frequency and finer current resolution vs. 30 µs variant, critical for low-noise microstepping.
Thermal resistance	23 °C/W (JP package, 4-layer JEDEC PCB); requires minimal heatsinking for 1.2 A operation at ≤85 °C ambient.
VREF input range	0–1.5 V; sets peak current via I_TRIP = VREF/(3×R_S), enabling precise 33%/66%/100% step current scaling.
Logic compatibility	3.0–5.5 V VDD; accepts direct interface with 3.3 V or 5 V microcontrollers without level-shifting.
Protection features	Integrated UVLO (VBB & VDD), thermal shutdown with 15 °C hysteresis, and crossover-current delay (300–1000 ns) prevent shoot-through.

Pinout & Package

Package: 48-pin LQFP (7 mm × 7 mm) with exposed thermal pad for enhanced heat dissipation; lead-free, 100% matte tin plating.

Pin/Terminal	Circuit Role	Design Meaning
PHASE1–PHASE4	Bridge direction control input	Determines winding polarity per full-bridge; enables full/half/quarter-step sequencing when combined with I0x/I1x.
I01–I04, I11–I14	Step mode select inputs	2-bit logic per bridge selects current percentage (0%, 33%, 66%, 100%) and decay behavior per step sequence table.
SENSE1–SENSE4	Current sense resistor return	Connects to low-side sense resistor; comparator monitors ±500 mV max to trigger PWM current limiting.
VREF1–VREF4	Analog current reference input	0–1.5 V input per bridge sets I_TRIP = VREF/(3×R_S); allows dynamic current scaling during motion profiles.
OUT1A–OUT4B	DMOS full-bridge output terminals	N-channel H-bridge outputs; each pair (e.g., OUT1A/OUT1B) drives one motor phase or DC motor terminal.
VBB1, VBB2	Motor supply inputs	Must be connected together near device; powers all bridges; decoupled with 100 µF + 0.1 µF capacitors.
VCP, CP1, CP2	Charge pump circuit terminals	VCP is reservoir node; CP1/CP2 require 0.1 µF ceramic capacitor to generate gate drive > VBB for high-side MOSFETs.
GND (Pins 16, 40)	Power and logic ground	Two dedicated GND pins; must connect to low-impedance star ground under exposed thermal pad to minimize bounce.

Key Features

Feature	Design Value
Mixed-decay PWM current regulation	30.1% fast decay + slow decay per 8.1 µs off-time reduces motor noise, improves step accuracy, and lowers power loss vs. pure fast decay.
Synchronous rectification	Enables low-R_DS(on) recirculation path during decay, cutting power dissipation by replacing body-diode conduction with MOSFET conduction.
Independent VREF per bridge	Four separate VREF inputs allow asymmetric current tuning across motors or windings-e.g., higher hold current on Phase 1, lower run current on Phase 2.
Exposed thermal pad (LQFP)	48-pin JP package includes solderable bottom pad; thermal vias to internal ground plane reduce R_θJA to 23 °C/W for reliable 1.2 A operation.
Integrated protection suite	UVLO on both VBB and VDD, thermal shutdown with hysteresis, and programmable blank time (0.7–1.3 µs) prevent false overcurrent trips during switching transients.

Applications

Industrial CNC Positioning	Medical Infusion Pumps
Use Scenario: Precision open-loop positioning of X/Y/Z axes in benchtop CNC mills using 1.8° bipolar stepper motors. IC Role / Device Role / Timing Role: Full-bridge driver executing quarter-step microstepping via PHASE/I0/I1 control and VREF-adjusted current per phase. Use Value: 8.1 µs off-time enables smoother low-speed motion and reduced resonance vs. 30 µs variants, critical for vibration-sensitive machining.	Use Scenario: Silent, accurate peristaltic motor control in portable IV infusion pumps requiring consistent flow rate and low acoustic signature. IC Role / Device Role / Timing Role: Dual stepper driver managing two independent pump heads with synchronized half-step sequencing and dynamic current reduction during dwell periods. Use Value: Mixed-decay mode cuts audible noise by >15 dB vs. fast-decay alternatives, meeting IEC 60601-1 acoustic limits for clinical environments.
Automated Laboratory Robotics	3D Printer Extruder & Bed Control
Use Scenario: Multi-axis sample handling robots moving pipette arms and slide trays with repeatable sub-millimeter accuracy. IC Role / Device Role / Timing Role: Quad full-bridge controller driving two steppers (arm + tray) plus two DC motors (gripper actuation and sensor positioning). Use Value: Independent VREF1–VREF4 inputs allow real-time current profiling-e.g., 100% torque for acceleration, 33% for holding-reducing system power by 40%.	Use Scenario: Simultaneous control of extruder stepper (filament feed), bed leveling steppers (Z-axis), and cooling fan DC motor in compact FDM printers. IC Role / Device Role / Timing Role: Single-chip solution consolidating three motor drivers, reducing BOM count and PCB area vs. discrete driver ICs. Use Value: 36 V rating supports high-torque 24 V extruder motors; synchronous rectification cuts thermal load on 4-layer board, eliminating need for external heatsinks.

Industrial CNC Positioning

Medical Infusion Pumps

Use Scenario: Precision open-loop positioning of X/Y/Z axes in benchtop CNC mills using 1.8° bipolar stepper motors.

IC Role / Device Role / Timing Role: Full-bridge driver executing quarter-step microstepping via PHASE/I0/I1 control and VREF-adjusted current per phase.

Use Value: 8.1 µs off-time enables smoother low-speed motion and reduced resonance vs. 30 µs variants, critical for vibration-sensitive machining.

Use Scenario: Silent, accurate peristaltic motor control in portable IV infusion pumps requiring consistent flow rate and low acoustic signature.

IC Role / Device Role / Timing Role: Dual stepper driver managing two independent pump heads with synchronized half-step sequencing and dynamic current reduction during dwell periods.

Use Value: Mixed-decay mode cuts audible noise by >15 dB vs. fast-decay alternatives, meeting IEC 60601-1 acoustic limits for clinical environments.

Automated Laboratory Robotics

3D Printer Extruder & Bed Control

Use Scenario: Multi-axis sample handling robots moving pipette arms and slide trays with repeatable sub-millimeter accuracy.

IC Role / Device Role / Timing Role: Quad full-bridge controller driving two steppers (arm + tray) plus two DC motors (gripper actuation and sensor positioning).

Use Value: Independent VREF1–VREF4 inputs allow real-time current profiling-e.g., 100% torque for acceleration, 33% for holding-reducing system power by 40%.

Use Scenario: Simultaneous control of extruder stepper (filament feed), bed leveling steppers (Z-axis), and cooling fan DC motor in compact FDM printers.

IC Role / Device Role / Timing Role: Single-chip solution consolidating three motor drivers, reducing BOM count and PCB area vs. discrete driver ICs.

Use Value: 36 V rating supports high-torque 24 V extruder motors; synchronous rectification cuts thermal load on 4-layer board, eliminating need for external heatsinks.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
A5988GJPTR-1-T	Pin-compatible 48-pin LQFP replacement; identical 8.1 µs off-time, same VREF/PHASE/I0/I1 interface, but adds SPI register access and improved thermal shutdown accuracy.	Supports closed-loop stall detection and dynamic current adjustment via SPI; suitable for next-gen designs requiring diagnostics and firmware configurability.	Select A5988GJPTR-1-T for new designs needing enhanced observability and programmable protection thresholds.
A3988SJPTR-T	Same 48-pin LQFP package and pinout, but uses 30 µs fixed off-time; otherwise identical electrical specs, protection, and feature set.	Higher off-time increases low-speed torque ripple and audible noise; acceptable where cost sensitivity outweighs acoustic or microstep fidelity requirements.	Select A3988SJPTR-T only for legacy cost-optimized designs where 30 µs timing suffices and discontinuation risk is managed.

Compared with A3988SJPTR-1-T, A5988GJPTR-1-T offers SPI configurability and tighter thermal monitoring for future-proofed motion control, while A3988SJPTR-T trades off microstepping smoothness for broader availability-but neither is pin-and-parameter drop-in due to off-time and feature divergence.

Availability

A3988SJPTR-1-T is available at Aetrix Electronics and suitable for industrial CNC positioning, medical infusion pumps, automated laboratory robotics, and 3D printer extruder & bed control requiring stable component supply despite end-of-life status.

Supply support for A3988SJPTR-1-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 is a U.S.-based designer of high-performance magnetic sensing and power ICs, headquartered in Manchester, NH, with deep expertise in motion control, current sensing, and automotive-grade reliability.

The A3988 product line was engineered specifically for precision open-loop stepper and DC motor control in space-constrained industrial and medical equipment, emphasizing thermal efficiency, low-noise operation, and integrated protection.

FAQ

Is A3988SJPTR-1-T still in production?

No. Allegro officially discontinued A3988SJPTR-1-T effective September 30, 2024. Samples are no longer available, and it is not recommended for new designs. Aetrix Electronics maintains limited legacy stock for existing production continuity, with full traceability and documented lot history for A3988SJPTR-1-T.

What is the key functional difference between A3988SJPTR-1-T and A3988SJPTR-T?

The core difference is fixed off-time: A3988SJPTR-1-T uses 8.1 µs, enabling higher PWM frequency and smoother microstepping, while A3988SJPTR-T uses 30 µs. All other specifications-including pinout, VREF range, protection features, and package-are identical for A3988SJPTR-1-T and A3988SJPTR-T.

Can A3988SJPTR-1-T drive 24 V stepper motors?

Yes. A3988SJPTR-1-T supports 8–36 V load supply (VBB), making it fully compatible with standard 24 V bipolar stepper motors. Its 1.2 A continuous rating per bridge and synchronous rectification ensure efficient operation at 24 V without external heatsinking under typical ambient conditions.

What does the "-1" suffix indicate in A3988SJPTR-1-T?

The "-1" suffix denotes the 8.1 µs fixed off-time variant of the A3988 family. This distinguishes it from the base A3988SJPTR-T (30 µs off-time) and reflects Allegro's performance binning for applications demanding higher PWM resolution and lower acoustic noise-key attributes of A3988SJPTR-1-T.

Does A3988SJPTR-1-T require external components for charge pump operation?

Yes. A3988SJPTR-1-T requires two external capacitors: a 0.1 µF ceramic capacitor between CP1 and CP2 for charge pumping, and another 0.1 µF ceramic capacitor between VCP and VBB to serve as the reservoir for high-side gate drive. These are mandatory for proper operation of A3988SJPTR-1-T.

A3988SJPTR-1-T Specifications

Product attributes: Attribute value

Manufacturer:: Allegro MicroSystems

Series:: -

Package/Case:: 48-LQFP Exposed Pad

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 (8)

Interface:: Parallel

Technology:: DMOS

Step Resolution:: 1, 1/2, 1/4

Applications:: General Purpose

Current - Output:: 1.2A

Voltage - Supply:: 3V ~ 5.5V

Voltage - Load:: 8V ~ 36V

Operating Temperature:: -20°C ~ 85°C (TA)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 48-LQFP-EP (7x7)

A3988SJPTR-1-T FAQ

1.How can I place an order for A3988SJPTR-1-T through Aetrix?

Please submit a Request for Quotation (RFQ) for A3988SJPTR-1-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 A3988SJPTR-1-T reliable?

The price and inventory of A3988SJPTR-1-T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for A3988SJPTR-1-T is usually 5 days.

3.What payment methods are accepted for A3988SJPTR-1-T?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for A3988SJPTR-1-T transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for A3988SJPTR-1-T?

A3988SJPTR-1-T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your A3988SJPTR-1-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 A3988SJPTR-1-T?

For technical support, including A3988SJPTR-1-T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your A3988SJPTR-1-T requirements.

6.How does Aetrix verify that A3988SJPTR-1-T is sourced from the original manufacturer or authorized distributors?

All A3988SJPTR-1-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 A3988SJPTR-1-T meets industry standards.

7.What is the process for return or replacement of A3988SJPTR-1-T?

All A3988SJPTR-1-T units undergo pre-shipment inspection (PSI). If there is an issue with A3988SJPTR-1-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 A3988SJPTR-1-T part is unused and in its original packaging.

Return procedure for A3988SJPTR-1-T:

1.Submit a request within 90 days.

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

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