My Inquiry
My Account
Allegro MicroSystems A4941GLPTR-T
- Part No.:
- A4941GLPTR-T
- Manufacturer:
- Allegro MicroSystems
- Category:
- Motor Drivers, Controllers
- Package:
- 16-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
A4941GLPTR-T.pdf
- Description:
- IC MOTOR DRIVER 5V-16V 16TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,883
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
A4941GLPTR-T from Allegro MicroSystems is a three-phase sensorless BLDC fan motor driver with BEMF sensing, 16-pin TSSOP package with exposed thermal pad, 5–16 V supply range, 1 A peak output current, and integrated lock detection and low-power standby mode - used in server cooling, telecom chassis fans, and industrial blowers.
For engineers reviewing the A4941GLPTR-T datasheet, A4941GLPTR-T pinout, A4941GLPTR-T application, or A4941GLPTR-T equivalent, key selection criteria include BEMF-based commutation without Hall sensors, PWM speed control with FG tach output, thermal performance on 2- vs 4-layer PCBs, and compatibility with center-tap or delta-wound motors.
Technical Context
The A4941GLPTR-T implements adaptive BEMF zero-crossing detection using motor center-tap (CTAP) or internally generated null point, with blanking and commutation delay timers to reject transients and optimize timing. It uses a six-state sequencer driving three half-bridge NMOS outputs with soft-switching control via SLEW pin.
Startup employs an internal oscillator until 96 valid FCOM pulses are detected; lock protection disables outputs for 5 s after 2 s of missing FG signal. Overcurrent protection is optional, set by external sense resistor with 200 mV threshold and 25 µs fault blanking.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage Range | 5–16 V - supports standard 12 V fan rails and accommodates brown-out margin down to 4.3 V UVLO |
| Peak Output Current | 1 A - sufficient for startup and locked-rotor conditions in ≤30 W fans |
| Thermal Resistance (RθJA) | 34 °C/W on 4-layer PCB - enables >1.5 W continuous power dissipation at TA = 105 °C |
| BEMF Sensing Method | Tri-stated winding vs CTAP comparison - eliminates Hall sensors and associated wiring/PCB area |
| FG Output Type | Open-drain - allows flexible pull-up to VBB or system logic voltage for tach feedback |
| Standby Current | 25–50 µA - entered by holding PWM low for 500 µs; reduces system idle power |
| Lock Detection Timeout | 2 s FG absence → 5 s disable + auto-restart - prevents thermal damage during stall |
Pinout & Package
Package: 16-pin TSSOP with exposed thermal pad (suffix LP), RoHS-compliant, 100% matte tin leadframe plating.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| OUTC (1) | Motor phase C output | Half-bridge high-/low-side NMOS terminal for 3-phase BLDC winding connection |
| CP1 (2), CP2 (3) | Charge pump inputs | Support gate drive voltage boost for high-side NMOS; require 0.1 µF ceramic caps |
| VCP (4) | Charge pump output | Provides boosted voltage for high-side gate drive; decoupled internally |
| GND (5, 11) | Power and signal ground | Must connect to exposed thermal pad and PCB ground plane via multiple vias |
| SLEW (6) | Soft-switching enable | Ground = enabled (reduces audible noise); open = disabled (prevents stall in high-L motors) |
| PWM (7) | Speed control input | Duty-cycle modulated signal (15–30 kHz); also serves as on/off switch into standby |
| FG (8) | Fan speed feedback | Open-drain pulse output (1 pulse per revolution × pole pairs); requires external pull-up |
| TEST (9) | Factory test only | No user connection; leave open-circuit in production designs |
| FC (10) | Force commutation timing | Selects startup oscillator period: GND=100 ms, VBB=50 ms, open=200 ms |
| CTAP (12) | Motor center-tap reference | Connect for wye-wound fans; leave open for delta - IC generates internal null point |
| SENSE (14) | Current limit sense | Optional 0.167 Ω resistor sets 1.2 A trip; connects to low-side current sense node |
| VBB (13) | Main supply input | 5–16 V motor power rail; requires 10 µF bulk capacitor placed adjacent to pin |
| OUTA (15), OUTB (16) | Motor phases A/B outputs | Identical half-bridge terminals; routed symmetrically to minimize layout EMI |
Key Features
| Feature | Design Value |
|---|---|
| Sensorless BEMF commutation | Eliminates Hall sensors and associated PCB traces, connectors, and calibration - reduces BOM cost and assembly complexity |
| Adaptive commutation delay | Adjusts timing dynamically based on measured BEMF zero crossings - maintains efficiency across speed/load variations |
| Integrated lock and thermal protection | Auto-disable on stalled rotor or junction temperature >165 °C - prevents MOSFET failure without external circuitry |
| Configurable startup timing (FC pin) | Three selectable oscillator periods (50/100/200 ms) - ensures reliable start for diverse motor inductance/resistance |
| Low-power standby mode | 25 µA quiescent current achieved by disabling drivers and logic - extends battery life in portable thermal systems |
Applications
| Data Center Server Fans | Telecom Chassis Cooling |
|---|---|
Use Scenario: High-reliability 48 V backplane-mounted fans maintaining CPU/GPU junction temperatures below 85 °C under variable compute load. IC Role / Device Role / Timing Role: Three-phase BLDC driver executing sensorless commutation with FG tach feedback to BMC for closed-loop thermal management. Use Value: Eliminates Hall sensor failures in high-vibration environments while enabling precise speed ramping via PWM to match real-time thermal demand. | Use Scenario: Compact 1U optical line terminal enclosures requiring silent operation and <100 ms thermal response to ambient spikes. IC Role / Device Role / Timing Role: Fan controller managing airflow across ASIC heat sinks using BEMF sensing and soft-switching (SLEW = GND) to suppress acoustic noise. Use Value: Reduces audible noise by >15 dB(A) versus hard-switched drivers while maintaining full-speed torque through adaptive commutation timing. |
| Industrial Blower Systems | Medical Imaging Cabinet Fans |
Use Scenario: Dust-prone factory-floor blowers moving air through HEPA filters in HVAC retrofit kits, operating continuously at 60–100 % duty cycle. IC Role / Device Role / Timing Role: Motor driver with overcurrent protection (SENSE resistor) and lock detection preventing thermal runaway during filter clogging. Use Value: Enables field-serviceable fan modules with self-diagnostic capability - FG loss triggers maintenance alert before catastrophic failure. | Use Scenario: MRI and CT scanner cabinets requiring EMI-quiet cooling with zero risk of Hall sensor drift affecting diagnostic accuracy. IC Role / Device Role / Timing Role: Sensorless fan driver delivering stable airflow while avoiding magnetic interference from Hall elements near sensitive detectors. Use Value: Guarantees immunity to stray magnetic fields and eliminates calibration drift over 10+ year service life - critical for FDA compliance. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar three-phase sensorless fan driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MP6532DJ-LF-Z | Integrated 3x half-bridge with 1.5 A peak rating; no CTAP pin - uses dual BEMF comparator architecture | Lacks center-tap support; requires delta-wound or externally referenced null point | Prefer when motor lacks CTAP and board space is constrained - smaller 3×3 mm QFN package |
| DRV10983ZRTVT | TI device with integrated LDO, I²C interface, and configurable startup profiles; 1.2 A peak rating | Requires microcontroller host for configuration; adds firmware overhead but enables dynamic parameter tuning | Choose when system already includes I²C master and needs runtime adjustment of slew rate or commutation angle |
Compared with MP6532DJ-LF-Z and DRV10983ZRTVT, the A4941GLPTR-T delivers simpler integration for fixed-function fan control, lower BOM count due to no external LDO or communication lines, and proven reliability in high-volume telecom deployments - ideal for cost-sensitive, standalone thermal management.
Availability
A4941GLPTR-T is available at Aetrix Electronics and suitable for data center thermal management, telecom chassis cooling, and industrial blower systems requiring stable component supply and long-term lifecycle support.
Supply support for A4941GLPTR-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, founded in 1989 and headquartered in Manchester, NH.
The A4941GLPTR-T belongs to Allegro's motor driver product line, engineered specifically for cost-optimized, sensorless BLDC fan control in high-reliability infrastructure equipment where Hall sensor failure modes must be eliminated.
FAQ
What is the function of the CTAP pin on the A4941GLPTR-T?
The CTAP pin on the A4941GLPTR-T provides the motor center-tap reference voltage for BEMF zero-crossing detection in wye-connected fans. When a center tap is unavailable (e.g., delta-wound motors), CTAP is left open and the A4941GLPTR-T internally generates a null reference point. This dual-mode support enables use with both common motor topologies without redesign.
How does the A4941GLPTR-T enter low-power standby mode?
The A4941GLPTR-T enters low-power standby mode when the PWM input is held low for 500 µs, reducing supply current to 25–50 µA. In this state, all motor outputs are disabled, BEMF sensing is halted, and the FG output goes high-impedance. Standby is exited automatically upon PWM returning high, resuming normal commutation after a brief startup sequence.
Can the A4941GLPTR-T drive delta-connected BLDC fans?
Yes, the A4941GLPTR-T can drive delta-connected BLDC fans. When CTAP is left open, the device synthesizes an internal null reference point for BEMF comparison. The functional block diagram and application notes confirm operation with both wye and delta configurations - no external components are required to switch between topologies.
What is the purpose of the SLEW pin on the A4941GLPTR-T?
The SLEW pin on the A4941GLPTR-T controls soft-switching activation: connecting it to GND enables slew-rate limiting on gate drive signals to reduce electromagnetic interference and audible motor noise. Leaving SLEW open disables soft switching - recommended for high-inductance motors prone to stall under soft-switched conditions, as documented in the Applications Information section.
Does the A4941GLPTR-T include overtemperature protection?
Yes, the A4941GLPTR-T includes thermal shutdown protection that activates at a junction temperature of 150–180 °C (typ. 165 °C), with 15 °C hysteresis for recovery. This protection is independent of external components and disables all outputs until temperature falls below the hysteresis threshold, preventing permanent damage during sustained overload or poor heatsinking.
A4941GLPTR-T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Allegro MicroSystems
- Series:
- -
- Package/Case:
- 16-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Motor Type - Stepper:
- -
- Motor Type - AC, DC:
- Brushless DC (BLDC)
- Function:
- Driver - Fully Integrated, Control and Power Stage
- Output Configuration:
- Half Bridge (3)
- Interface:
- PWM
- Technology:
- Power MOSFET
- Step Resolution:
- -
- Applications:
- Fan Motor Driver
- Current - Output:
- 500mA
- Voltage - Supply:
- 5V ~ 16V
- Voltage - Load:
- -
- Operating Temperature:
- -40°C ~ 105°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-eTSSOP-EP
A4941GLPTR-T FAQ
1.How can I place an order for A4941GLPTR-T through Aetrix?
Please submit a Request for Quotation (RFQ) for A4941GLPTR-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 A4941GLPTR-T reliable?
The price and inventory of A4941GLPTR-T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for A4941GLPTR-T is usually 5 days.
3.What payment methods are accepted for A4941GLPTR-T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for A4941GLPTR-T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for A4941GLPTR-T?
A4941GLPTR-T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your A4941GLPTR-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 A4941GLPTR-T?
For technical support, including A4941GLPTR-T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your A4941GLPTR-T requirements.
6.How does Aetrix verify that A4941GLPTR-T is sourced from the original manufacturer or authorized distributors?
All A4941GLPTR-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 A4941GLPTR-T meets industry standards.
7.What is the process for return or replacement of A4941GLPTR-T?
All A4941GLPTR-T units undergo pre-shipment inspection (PSI). If there is an issue with A4941GLPTR-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 A4941GLPTR-T part is unused and in its original packaging.
Return procedure for A4941GLPTR-T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
A4941GLPTR-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…
