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Allegro MicroSystems A4946GLPTR-T
- Part No.:
- A4946GLPTR-T
- Manufacturer:
- Allegro MicroSystems
- Category:
- Motor Drivers, Controllers
- Package:
- 16-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
A4946GLPTR-T.pdf
- Description:
- IC FAN DRIVER BLDC TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:8,000
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Product details
Overview
A4946GLPTR-T from Allegro MicroSystems is a three-phase sinusoidal motor driver IC with integrated power bridge, designed for automotive blower and fan control. It delivers up to 1.63 A peak phase current, operates from 6.5–28 V supply, uses Hall-effect rotor position sensing, and supports both analog voltage and PWM speed demand inputs for precise speed regulation in 12 V automotive power net systems.
For engineers reviewing the A4946GLPTR-T datasheet, A4946GLPTR-T pinout, A4946GLPTR-T application, or A4946GLPTR-T equivalent, key selection considerations include its 16-pin TSSOP-LP package with exposed thermal pad, full sinusoidal commutation for low audible noise, integrated lock detection and overtemperature protection, and dual-mode speed control (analog 0–4.3 V or PWM 12.5–100% duty cycle).
Technical Context
The A4946GLPTR-T implements sensor-based trapezoidal-to-sinusoidal mode transition using Hall inputs (HAP/HAM, HBP/HBM, HCP/HCM) and internal commutation logic. Its 30 kHz PWM generator produces 120°-spaced sinusoidal drive waveforms synchronized to rotor position, with dynamic phase advance enabled via PHA pin.
Speed control is implemented through an internal 9-bit ADC (for analog SPD input) or duty-cycle decoder (for digital SPD input), both mapped linearly to 25–100% motor speed demand. Protection includes fixed off-time current limiting (24 μs), VBB overvoltage/undervoltage detection (32 V / 3.6 V thresholds), and thermal shutdown at 170°C with 15°C hysteresis.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage Range | 6.5–28 V functional range; enables direct connection to automotive 12 V net with robust operation across battery transients. |
| Peak Phase Current | 1.63 A (typ); sets maximum torque capability while maintaining safe junction temperature under thermal derating. |
| PWM Frequency | 30 kHz ±2 kHz; suppresses audible motor noise and avoids EMI-sensitive bands in automotive environments. |
| Current Limit Threshold | 1.63 A per phase; provides fast, fixed off-time overcurrent protection without external sensing components. |
| Thermal Resistance (RθJA) | 34 °C/W on 4-layer PCB; defines minimum copper area and via count needed to sustain 1.25 A continuous phase current at 80°C ambient. |
| Speed Input Options | Analog 0–4.3 V or PWM 12.5–100% duty cycle; eliminates need for external variable power supply or microcontroller PWM generation. |
| FG Output | Digital pulse per electrical revolution; provides direct tachometer feedback for closed-loop speed monitoring without additional circuitry. |
Pinout & Package
Package: 16-pin TSSOP with exposed thermal pad (LP package), 4.4 mm × 5.0 mm × 1.2 mm, lead-free with 100% matte-tin plating. Thermal pad must be connected to GND for effective heat dissipation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| HAP / HAM | Hall element A differential input | Accepts ±30 mVpk-pk Hall signal; common-mode range 1–4 V allows series/parallel Hall sensor configurations. |
| HBP / HBM | Hall element B differential input | Same electrical specs as HAP/HAM; enables 120° electrical spacing for accurate rotor position decoding. |
| HCP / HCM | Hall element C differential input | Completes 3-channel Hall interface; internal comparators provide hysteresis to reject noise near commutation points. |
| SPD | Speed demand input | Accepts either analog voltage (0–4.3 V) or PWM signal (12.5–100% duty cycle) based on SEL state. |
| SEL | Speed input mode select | Low = analog voltage mode; high = PWM duty cycle mode; internal pull-down ensures default analog operation. |
| PHA | Phase advance enable | High or open = dynamic phase advance active (up to 13.1° electrical); low = no advance applied. |
| FG | Speed output indicator | Open-drain digital output, one pulse per electrical revolution; directly interfaces with MCU GPIO or optocoupler. |
| OUTA / OUTB / OUTC | Motor phase outputs | Three half-bridge outputs with 0.54 Ω RDS(on) (25°C); support sinusoidal PWM drive with dead time of 400 ns. |
| VBB | Main supply input | 6.5–28 V motor supply and internal regulator input; requires ≥10 μF low-ESR electrolytic + 100 nF ceramic decoupling. |
| VREF | 5 V regulated output | 5.0 V ±2.5%, supplies Hall sensors and internal analog circuits; requires 220 nF ceramic decoupling to GND. |
| GND | Ground reference | Analog/digital/power return; connects to exposed thermal pad for optimal thermal performance. |
| PAD | Exposed thermal pad | Must be soldered to GND plane with thermal vias; primary path for heat removal from power bridge MOSFETs. |
Key Features
| Feature | Design Value |
|---|---|
| Full 3-phase sinusoidal drive | Reduces motor audible noise and vibration by replacing trapezoidal excitation with smooth 120°-spaced sine-wave currents. |
| Dynamic phase advance | Adjusts excitation timing up to 13.1° electrical based on FG frequency, improving motor efficiency at higher speeds. |
| Integrated lock detection | Monitors commutation period (tCOMM); disables outputs after 1 s if tCOMM > 52 ms, then attempts auto-restart every 8 s. |
| Dual-mode speed control | Eliminates external DAC or PWM generator-supports direct MCU GPIO (PWM) or DAC output (analog) on SPD pin. |
| Robust fault protection | Combines VBB OV/UV (32 V / 3.6 V), short-circuit detection (VDS > 1.6 V), and thermal shutdown (170°C) with automatic recovery sequencing. |
Applications
| Automotive HVAC Blower | Engine Bay Cooling Fan |
|---|---|
Use Scenario: Variable-speed cabin air delivery in automotive heating, ventilation, and air conditioning systems. IC Role / Device Role / Timing Role: Three-phase sinusoidal motor driver with Hall-based commutation and FG tach feedback. Use Value: Enables quiet, energy-efficient airflow control across full speed range without mechanical dampers or external controllers. | Use Scenario: Thermally triggered radiator cooling fan in engine compartment with wide ambient temperature range (–40°C to 105°C). IC Role / Device Role / Timing Role: Motor driver with integrated overtemperature shutdown and VBB transient tolerance up to 50 V. Use Value: Maintains reliable operation during load dump events and prevents thermal runaway without external thermal sensors or shutdown logic. |
| Passenger Compartment Air Circulation | Electric Power Steering (EPS) Auxiliary Fan |
Use Scenario: Low-noise air recirculation fan behind dashboard, requiring minimal acoustic signature. IC Role / Device Role / Timing Role: Sinusoidal PWM driver with 30 kHz switching and dynamic phase advance. Use Value: Reduces audible whine below 20 kHz and improves torque linearity versus trapezoidal drivers, enhancing passenger comfort. | Use Scenario: Duty-cycled auxiliary cooling for EPS motor and controller during high-torque steering maneuvers. IC Role / Device Role / Timing Role: Speed-controlled fan driver with lock detection and soft-start to prevent inrush current spikes. Use Value: Prevents thermal throttling of EPS system by delivering precise airflow on demand while avoiding voltage droop on shared 12 V rail. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar three-phase sinusoidal fan driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| DRV10983ZRTVT | Integrated FETs rated for 2 A peak; lacks Hall differential inputs-requires single-ended Hall or back-EMF sensing. | Designed for sensorless BLDC operation; not suitable for Hall-based systems without redesign. | Select only if migrating from Hall to back-EMF commutation and higher current is required. |
| MP6532GQ-Z | Supports 1.5 A peak; includes SPI interface for diagnostics and parameter tuning; no FG output pin. | Requires MCU host for configuration and speed reporting; adds software overhead but enables real-time fault logging. | Choose when system-level diagnostics, programmable protection thresholds, or multi-motor synchronization are needed. |
Compared with A4946GLPTR-T, DRV10983ZRTVT offers higher current but removes Hall interface compatibility, while MP6532GQ-Z adds configurability at the cost of FG tach simplicity and increased firmware dependency.
Availability
A4946GLPTR-T is available at Aetrix Electronics and suitable for automotive HVAC blowers, engine bay cooling fans, and passenger compartment air circulation systems requiring stable component supply, AEC-Q100 compliance, and long-term production continuity.
Supply support for A4946GLPTR-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 and manufacturer of high-performance magnetic sensing and power IC solutions, founded in 1989 and headquartered in Worcester, Massachusetts.
The A4946GLPTR-T belongs to Allegro's automotive-grade motor driver product line, engineered specifically for low-noise, high-reliability fan and blower control in 12 V vehicle networks with stringent thermal and fault-tolerance requirements.
FAQ
What is the maximum continuous motor phase current supported by the A4946GLPTR-T?
The A4946GLPTR-T supports up to 1.25 A average continuous phase current at 80°C ambient temperature, assuming a 4-layer PCB layout with RθJA = 34 °C/W. This value is thermally limited-not current-limited-and decreases with higher ambient temperature or poorer board thermal design. Peak phase current is 1.63 A (typ), enforced by internal fixed off-time current limiting.
How does the A4946GLPTR-T handle motor lock detection and recovery?
The A4946GLPTR-T detects lock by monitoring commutation period (tCOMM). If tCOMM exceeds 52 ms after 1 s startup time (tST), it disables all outputs for 8 s (tLD), then attempts restart while SPD demand remains >12.5%. Recovery requires reducing SPD below 12.5% to reset the fault latch. This behavior is fully autonomous-no MCU intervention is needed for basic lock handling.
Can the A4946GLPTR-T operate with single-ended Hall sensors?
No-the A4946GLPTR-T requires differential Hall inputs (HAP/HAM, HBP/HBM, HCP/HCM) with ±30 mVpk-pk sensitivity and 1–4 V common-mode range. It does not support single-ended Hall sensors or back-EMF sensing. The internal comparators are optimized for differential signals to reject noise in automotive environments, and the commutation logic depends on valid Hall state transitions across all three channels.
What are the exact voltage thresholds for analog speed control on the SPD pin of the A4946GLPTR-T?
For analog speed control (SEL = low), the A4946GLPTR-T interprets SPD voltage as follows: motor stops below 0.5 V; starts at 1.12 V (25% speed); reaches full speed at 4.25 V (100% speed); and has hysteresis of ~0.5 V between on/off transitions. These values are specified in the Electrical Characteristics table as VSPDON = 1.12 V (min), VSPDMAX = 4.25 V (typ), and VSPDOFF = 0.58 V (typ).
Is the exposed thermal pad on the A4946GLPTR-T electrically connected internally?
Yes-the exposed thermal pad on the A4946GLPTR-T is internally connected to GND. It must be soldered to a GND plane on the PCB with multiple thermal vias to ensure effective heat transfer and meet RθJA specifications. Leaving the pad unconnected or floating violates the thermal design requirements and risks junction temperature exceedance under load.
A4946GLPTR-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:
- Active
- Motor Type - Stepper:
- Multiphase
- Motor Type - AC, DC:
- AC, Synchronous
- Function:
- Driver - Fully Integrated, Control and Power Stage
- Output Configuration:
- Half Bridge (3)
- Interface:
- -
- Technology:
- NMOS
- Step Resolution:
- -
- Applications:
- -
- Current - Output:
- 1.91A
- Voltage - Supply:
- 4.75V ~ 5.25V
- Voltage - Load:
- 4.75V ~ 5.25V
- Operating Temperature:
- -40°C ~ 105°C
- Grade:
- Automotive
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-eTSSOP-EP
A4946GLPTR-T FAQ
1.How can I place an order for A4946GLPTR-T through Aetrix?
Please submit a Request for Quotation (RFQ) for A4946GLPTR-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 A4946GLPTR-T reliable?
The price and inventory of A4946GLPTR-T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for A4946GLPTR-T is usually 5 days.
3.What payment methods are accepted for A4946GLPTR-T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for A4946GLPTR-T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for A4946GLPTR-T?
A4946GLPTR-T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your A4946GLPTR-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 A4946GLPTR-T?
For technical support, including A4946GLPTR-T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your A4946GLPTR-T requirements.
6.How does Aetrix verify that A4946GLPTR-T is sourced from the original manufacturer or authorized distributors?
All A4946GLPTR-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 A4946GLPTR-T meets industry standards.
7.What is the process for return or replacement of A4946GLPTR-T?
All A4946GLPTR-T units undergo pre-shipment inspection (PSI). If there is an issue with A4946GLPTR-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 A4946GLPTR-T part is unused and in its original packaging.
Return procedure for A4946GLPTR-T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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