My Inquiry
My Account
Allegro MicroSystems A3998SETTR-T
- Part No.:
- A3998SETTR-T
- Manufacturer:
- Allegro MicroSystems
- Category:
- Motor Drivers, Controllers
- Package:
- 32-VFQFN Exposed Pad
- Datasheet:
-
A3998SETTR-T.pdf
- Description:
- IC MTR DRVR BIPOLAR 3-5.5V 32QFN
- Quantity:
- Payment:
- Shipping:
Inventory:1,308
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
A3998SETTR-T from Allegro MicroSystems is a dual DMOS full-bridge motor driver IC with integrated 3.3–5 V switching regulator and 1–2.5 V linear regulator, rated for ±1.5 A per bridge at 50 V, supporting stepper or dual DC motor control in office automation equipment.
For engineers reviewing the A3998SETTR-T datasheet, A3998SETTR-T pinout, A3998SETTR-T application, or A3998SETTR-T equivalent, key selection considerations include serial port programmability, fixed off-time PWM decay control, synchronous rectification, thermal shutdown (165°C typ), and QFN-32 ET package thermal performance (RθJA = 30°C/W on 4-layer PCB).
Technical Context
The A3998SETTR-T integrates two independent DMOS full bridges with internal PWM current regulation using adjustable fixed off-time (2–64 µs) and programmable decay modes (mixed/fast/slow). Each bridge supports 4-bit microstepping via DAC-controlled current ratio (0–100% in 16 steps) and features blanking timers (1–6 µs) to suppress sense transient false triggers.
Its dual-regulator architecture combines a peak-current-mode buck switcher (VOUT1: 3.3–5 V, 1 A) with an adjustable LDO (VOUT2: 1–2.5 V, 500 mA), where the buck output feeds the LDO input-enabling high-efficiency system power partitioning for microprocessor/DSP and logic rails while minimizing die dissipation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Bridge Output Rating | ±1.5 A continuous, 50 V max - supports high-torque stepper or dual brushed DC motors in printer paper path and scanner actuation. |
| Switching Regulator Output | 3.3–5 V, adjustable, 1 A - powers external microprocessors or DSPs; uses internal oscillator (4 MHz typ) and fixed off-time control. |
| Linear Regulator Output | 1–2.5 V, adjustable, 500 mA - supplies low-voltage logic; configurable for internal pass element or external N-FET gate drive to reduce thermal load. |
| Current Sensing | VSENSE threshold: 0.52 V DC - enables precise current limiting via external sense resistors (RS); supports foldback OCP during overload. |
| Thermal Protection | Shutdown at TJ = 165°C (typ), 20°C hysteresis - prevents latch-up under sustained overload; drivers and switcher disabled, config register preserved. |
| Serial Interface | 4-wire STB/CLK/DATA/SLEEPN - writes volatile configuration register (4 × 16-bit words) for decay mode, blank time, fast decay duration, and phase control. |
| Package Thermal Resistance | RθJA = 30°C/W (4-layer JEDEC PCB) - enables stable operation up to 85°C ambient with proper copper pour and thermal pad soldering. |
Pinout & Package
Supplied in a lead-free, 32-contact QFN package (5 × 5 mm, 0.90 mm height) with exposed thermal pad (suffix ET); requires soldering of PAD to PCB ground plane for thermal and electrical integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GND (Pins 1,13,32) | Power Ground Reference | Common return for motor, switcher, and logic grounds; must be low-impedance connection to thermal pad. |
| VBB (Pins 10,16) | Motor & Switcher Supply Input | Primary high-side rail (9–50 V); powers both full bridges and buck switcher; UVLO threshold 7.1 V (typ). |
| OUT1A/OUT1B, OUT2A/OUT2B (Pins 15,17,9,11) | Full-Bridge Output Terminals | DMOS H-bridge outputs; each pair drives one motor winding or DC motor; RDS(on) = 0.5 Ω (typ) per FET. |
| SENSE1/SENSE2 (Pins 14,12) | Current Sense Inputs | Low-side sense resistor connections; 0.52 V full-scale threshold enables accurate ITRIP setting per bridge. |
| SW1 (Pin 18) | Buck Switch Node | Internal high-side switch output; connects to external inductor (L1) and diode (D1); requires low-ESR ceramic output cap (220 µF). |
| VIN (Pin 25) | LDO Input / Logic Supply | Accepts 3.3–5 V from buck output or external source; powers internal logic and LDO pass element; UVLO at 2.8 V (typ). |
| CSN (Pin 24) | Current Sense/Regulator Select | Configures LDO mode: tied to VREG → internal pass element (525–750 mA limit); tied to sense resistor → external FET control. |
| STB/CLK/DATA/SLEEPN (Pins 6,4,5,3) | Serial Port Control | 4-wire interface for writing configuration register; SLEEPN active-low resets register and enters standby (regulators remain active). |
Key Features
| Feature | Design Value |
|---|---|
| Synchronous Rectification | Reduces conduction loss by enabling low-RDS(on) MOSFETs instead of body diodes during decay; configurable as active (zero-current turn-off) or passive mode. |
| Programmable Decay Modes | Mixed, fast, or slow decay per bridge selected via serial port; mixed mode uses user-defined fast-decay duration within fixed off-time window. |
| Integrated Dual Regulators | Eliminates need for external DC/DC + LDO combo; buck output (3.3–5 V) feeds LDO input, enabling efficient 1–2.5 V logic rail generation with minimal board space. |
| Fixed Off-Time PWM Control | Per-bridge off-time adjustable from 2–64 µs (in 2 µs steps) using 5-bit serial register; enables precise current ripple control across wide motor speed ranges. |
| OCP with Fault Latching | Overcurrent event resets configuration register to POR defaults; latched fault cleared only by power cycle or SLEEPN toggle - ensures deterministic recovery in safety-critical motion systems. |
Applications
| Printer Paper Feed System | Document Scanner Carriage Drive |
|---|---|
|
Use Scenario: Precise bidirectional transport of paper through rollers and registration sensors in laser and inkjet printers. IC Role / Device Role / Timing Role: Dual full-bridge driver controls two DC motors (pickup and feed) or one bipolar stepper for position-critical paper advancement. Use Value: 4-bit microstepping and programmable decay ensure smooth, low-vibration motion; integrated regulators simplify power tree for MCU and sensor subsystems. |
Use Scenario: Linear positioning of optical carriage across document platen with repeatable start/stop and acceleration profiles. IC Role / Device Role / Timing Role: Single full-bridge drives stepper motor; serial port configures current ratio and decay to match inertia and minimize resonance at scan speeds. Use Value: Synchronous rectification cuts heat rise by >30% vs. diode-based recirculation; thermal shutdown protects against jam-induced stall conditions. |
| Office Copier Duplex Path | Automatic Document Feeder (ADF) |
|
Use Scenario: Reversing paper path for duplex printing, requiring rapid direction reversal and torque consistency across varying media weights. IC Role / Device Role / Timing Role: Dual bridge operates in independent mode - one for forward path, one for reverse path - with coordinated phase control via serial port. Use Value: ±1.5 A rating sustains peak torque during thick-paper handling; UVLO and OCP prevent misfeeds from supply sag or mechanical bind. |
Use Scenario: High-speed sheet separation and transport in multi-page scanning, demanding reliable start-stop and skew correction. IC Role / Device Role / Timing Role: Full-bridge drives DC motor with ENBx-chopped external PWM; serial port sets blank time to reject clutch engagement transients. Use Value: Adjustable blank time (1–6 µs) prevents false OCP trips during solenoid actuation; PMON flag signals VBB health to host controller. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual full-bridge motor driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TB6600HG | Higher voltage (50 V), higher current (4 A), but no integrated regulators; requires external 5 V and 3.3 V supplies. | Targeted at CNC and industrial stepper systems; lacks serial configuration and microstepping resolution (only 1–32 step modes). | Choose TB6600HG when higher current and ruggedized packaging are required, and external power management is already in place. |
| DRV8825 | Lower voltage (45 V), lower current (2.2 A), integrated 3.3 V LDO only (no buck); microstepping up to 1/32, but no dual-regulator architecture. | Designed for compact 3D printer extruder/carriage boards; lacks dual-motor independent control and programmable decay timing. | Choose DRV8825 for space-constrained single-stepper applications where integrated LDO suffices and serial configurability is not needed. |
Compared with TB6600HG and DRV8825, the A3998SETTR-T uniquely integrates dual regulated rails (buck + LDO), serial-programmable decay timing, and synchronous rectification - making it optimal for office automation systems requiring self-contained, thermally efficient, and software-configurable motor control without external power ICs.
Availability
A3998SETTR-T is available at Aetrix Electronics and suitable for printer paper feed systems, document scanner carriage drives, copier duplex paths, and automatic document feeders requiring stable component supply despite end-of-life status.
Supply support for A3998SETTR-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, specializing in motion control, current sensing, and motor driver solutions for industrial and automotive markets.
The A3998SETTR-T belongs to Allegro's legacy motor driver product line, engineered specifically for office automation equipment requiring integrated power management, robust thermal protection, and flexible serial configuration for stepper and DC motor control.
FAQ
Is the A3998SETTR-T still in production?
No, the A3998SETTR-T is a discontinued product. Allegro MicroSystems ceased production as of December 28, 2019. It is not recommended for new design applications, and samples are no longer available. Aetrix Electronics maintains limited legacy stock for existing production continuity and repair programs.
What does the "ET" suffix in A3998SETTR-T signify?
"ET" denotes the 32-contact QFN package with exposed thermal pad (5 × 5 mm, 0.90 mm height), lead-free construction, and 100% matte-tin leadframe plating. This package variant is optimized for thermal dissipation in motor driver applications and requires proper PCB land pattern and thermal via design per Allegro's AN299007 layout guidelines.
Can the A3998SETTR-T drive a stepper motor in microstepping mode?
Yes, the A3998SETTR-T supports 4-bit microstepping (16 microsteps per full step) via its serial port–configured DAC, which adjusts current ratio per bridge from 0% to 100% in discrete steps. This enables smooth, low-resonance motion control essential for precision office automation mechanisms.
How does the synchronous rectification feature improve efficiency in the A3998SETTR-T?
Synchronous rectification replaces high-loss body diode conduction with low-RDS(on) MOSFET switching during current decay, reducing power dissipation by up to 40% compared to diode-based recirculation. In the A3998SETTR-T, this feature is configurable per bridge via serial port bit D11 (active/passive mode) and works with all decay modes.
What happens during an overcurrent fault on the A3998SETTR-T?
When overcurrent is detected, the A3998SETTR-T latches a fault, disables all motor outputs, and resets the serial configuration register to its power-on reset (POR) default state. The fault remains latched until either a full power cycle occurs or the SLEEPN pin is toggled - ensuring predictable recovery behavior in safety-critical motion systems.
A3998SETTR-T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Allegro MicroSystems
- Series:
- -
- Package/Case:
- 32-VFQFN 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 (4)
- Interface:
- Serial
- Technology:
- DMOS
- Step Resolution:
- 1, 1/2, 1/4, 1/8
- Applications:
- General Purpose
- Current - Output:
- 1.5A
- Voltage - Supply:
- 3V ~ 5.5V
- Voltage - Load:
- 9V ~ 50V
- Operating Temperature:
- -20°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 32-QFN (5x5)
A3998SETTR-T FAQ
1.How can I place an order for A3998SETTR-T through Aetrix?
Please submit a Request for Quotation (RFQ) for A3998SETTR-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 A3998SETTR-T reliable?
The price and inventory of A3998SETTR-T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for A3998SETTR-T is usually 5 days.
3.What payment methods are accepted for A3998SETTR-T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for A3998SETTR-T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for A3998SETTR-T?
A3998SETTR-T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your A3998SETTR-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 A3998SETTR-T?
For technical support, including A3998SETTR-T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your A3998SETTR-T requirements.
6.How does Aetrix verify that A3998SETTR-T is sourced from the original manufacturer or authorized distributors?
All A3998SETTR-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 A3998SETTR-T meets industry standards.
7.What is the process for return or replacement of A3998SETTR-T?
All A3998SETTR-T units undergo pre-shipment inspection (PSI). If there is an issue with A3998SETTR-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 A3998SETTR-T part is unused and in its original packaging.
Return procedure for A3998SETTR-T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
A3998SETTR-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…
