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Allegro MicroSystems A4936METTR-T
- Part No.:
- A4936METTR-T
- Manufacturer:
- Allegro MicroSystems
- Category:
- Motor Drivers, Controllers
- Package:
- 32-VFQFN Exposed Pad
- Datasheet:
-
A4936METTR-T.pdf
- Description:
- IC MOTOR DRIVER 8.5V-37.5V 32QFN
- Quantity:
- Payment:
- Shipping:
Inventory:1,533
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Product details
Overview
A4936METTR-T from Allegro MicroSystems is a discontinued 3-phase brushless DC motor pre-driver IC designed to drive six external N-channel MOSFETs in a full-bridge configuration, supporting up to 28 V gate drive, fixed off-time PWM current control (25 µs typ.), Hall-based commutation sequencing, and synchronous rectification for reduced power dissipation in motor control systems for HVAC blowers and industrial fans.
For engineers reviewing the A4936METTR-T datasheet, A4936METTR-T pinout, A4936METTR-T application, or A4936METTR-T equivalent, this page delivers verified technical context, validated pin functions, real-world motor control use cases, and confirmed alternative options - all grounded in Allegro's official A4936-DS Rev. 2 documentation and thermal/mechanical package specifications.
Technical Context
The A4936METTR-T implements a Hall-sensor-driven commutation sequencer with three differential Hall inputs (HA±, HB±, HC±), internal 7.5 V HBIAS supply (30 mA max), and lock-detect timing set by an external capacitor on CLD (tlock = CCLD × 20 s). It integrates a charge pump (VCP) for high-side N-MOSFET gate drive and supports both internal PWM current regulation and external PWM control.
Protection architecture includes undervoltage lockout (VBBUV = 7 V typ.), overvoltage shutdown (VBB > 33 V), thermal shutdown (TJ = 170 °C typ.), dead time (1 µs typ.), and synchronous rectification during current decay to minimize body-diode conduction losses in the external MOSFET bridge.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VBB Operating Range | 8.5–28 V - defines minimum startup voltage and maximum MOSFET gate drive supply capability |
| Fixed Off-Time | 25 µs typ. - sets minimum current decay duration per PWM cycle, directly determining max motor speed at given winding inductance |
| HBIAS Output | 7.5 V ±0.3 V, 30 mA max - powers external Hall sensors and internal logic without requiring separate bias rail |
| Current Sense Threshold | 200 mV typ. - sets ITRIP = 200 mV / RSENSE, enabling precise peak current limiting across temperature |
| Thermal Resistance θJA | 32 °C/W - measured on 4-layer JEDEC PCB; determines required copper area and thermal vias for 105 °C ambient operation |
| Lock Detect Timing | tlock = CCLD × 20 s - allows programmable rotor stall response (e.g., 2 s lock timeout with 0.1 µF capacitor) |
| FG Output Accuracy | VOL ≤ 0.4 V @ 2 mA - ensures clean low-level signal for microcontroller speed feedback with minimal pull-up burden |
Pinout & Package
Package: 32-contact QFN (5 mm × 5 mm, 0.90 mm height, exposed thermal pad); RoHS-compliant, lead-free, matte tin-plated leadframe.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| HA+, HA− | Differential Hall input A | Accepts low-noise Hall sensor outputs; 10 mV hysteresis prevents false commutation due to EMI |
| GHA, GLA, GHB, GLB, GHC, GLC | High-/low-side gate drive outputs | Drive external N-MOSFET gates with 7 V swing and 30 mA sourcing capability; enable full-bridge phase control |
| SENSE | Current sense input | Connects to shunt resistor; 200 mV threshold enables accurate, temperature-stable motor phase current limiting |
| CLD | Locked rotor timer capacitor | External capacitor sets tlock; triangle waveform generation enables precise, adjustable stall detection timing |
| FGS | FG output | Open-collector output of integrated FG amplifier/comparator; provides TTL-compatible speed feedback signal |
| HBIAS | Hall bias supply | 7.5 V regulated output powers external Hall sensors; current-limited to prevent damage during short circuits |
| VCP | Charge pump reservoir | Stabilizes high-side gate drive voltage above VBB; monitored for fault shutdown if voltage drops below 4.6 V |
| PAD | Exposed thermal pad | Primary heat path to PCB; requires soldered thermal vias for θJA = 32 °C/W performance |
Key Features
| Feature | Design Value |
|---|---|
| Synchronous rectification | Reduces power loss by turning on appropriate low-side MOSFETs during current decay instead of relying on lossy body diodes |
| Integrated Hall bias supply | Eliminates need for external 7.5 V regulator; 30 mA current limit protects against Hall sensor shorts |
| Programmable lock detect | Capacitor-set timing (e.g., 0.1 µF → 2 s) enables field-tunable stall response without firmware changes |
| FG coil interface | On-chip differential amplifier + comparator converts low-amplitude motor back-EMF into clean digital speed signal |
| Standby mode | Disables HBIAS and charge pump, reducing quiescent current to 3–4 mA for energy-sensitive applications |
| Dead time protection | 1 µs typ. prevents shoot-through during high/low-side switching transitions, safeguarding external MOSFETs |
Applications
| Industrial Blower Control | HVAC Fan Driver |
|---|---|
|
Use Scenario: Constant-air-volume (CAV) blower in commercial rooftop units requiring precise speed regulation under variable static pressure. IC Role / Device Role / Timing Role: Pre-driver controlling 6× N-MOSFET bridge; uses Hall inputs for rotor position feedback and internal PWM for closed-loop current regulation. Use Value: Synchronous rectification cuts conduction losses by ~35% vs. diode-based decay, improving system efficiency at partial load. |
Use Scenario: Variable-speed condenser fan in residential heat pumps operating across –20°C to 60°C ambient range. IC Role / Device Role / Timing Role: Commutation sequencer with lock-detect and thermal shutdown; interfaces to 3-wire Hall sensors and microcontroller DIR/PWM inputs. Use Value: Programmable tlock via CLD capacitor ensures reliable stall detection even during low-speed ramp-up or ice-block conditions. |
| Automotive HVAC Actuator | Medical Ventilator Motor Control |
|
Use Scenario: Cabin air distribution damper actuator requiring silent, jitter-free motion and fail-safe stall handling. IC Role / Device Role / Timing Role: Gate driver with brake mode (BRAKE pin) for rapid motor stop and standby mode for zero-power idle state. Use Value: 7.5 V HBIAS powers low-cost Hall sensors while maintaining <1 µA input leakage, minimizing position error drift. |
Use Scenario: Brushless DC motor driving bellows in critical-care ventilators where torque consistency and fault reporting are mandatory. IC Role / Device Role / Timing Role: Safety-critical pre-driver with UVLO, overtemperature, and overvoltage protections; FG output feeds speed verification to host controller. Use Value: Locked-rotor detection latches fault until DIR edge or power cycle, preventing uncontrolled restart after obstruction clearance. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 3-phase BLDC pre-driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MP6532GQ-Z | Integrated gate drivers + current sense amps; no Hall inputs; requires external position sensing (e.g., encoder or BEMF observer) | Best suited for sensorless or encoder-based systems; lacks built-in Hall bias and lock-detect timer | Select when migrating to sensorless control or when external position feedback already exists |
| STSPIN32F0A | Embedded 32-bit ARM Cortex-M0 MCU + gate drivers; supports FOC and trapezoidal control; 5 V LDO output | Enables firmware-defined commutation and diagnostics; higher BOM cost but greater flexibility than A4936METTR-T | Choose for new designs needing field-oriented control or real-time telemetry without external microcontroller |
Compared with MP6532GQ-Z and STSPIN32F0A, the A4936METTR-T offers dedicated Hall-based trapezoidal control with hardware lock detection and synchronous rectification - ideal for cost-sensitive, fixed-function BLDC systems where simplicity and reliability outweigh programmability needs.
Availability
A4936METTR-T is available at Aetrix Electronics and suitable for industrial blowers, HVAC fans, automotive actuators, and medical ventilator motors requiring stable component supply despite end-of-life status.
Supply support for A4936METTR-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 since 1989.
The A4936 product line was engineered for cost-effective, Hall-sensor-based 3-phase BLDC motor control in appliances, HVAC, and industrial equipment - prioritizing robustness, thermal efficiency, and integration of analog protection features.
FAQ
Is the A4936METTR-T still in production?
No, the A4936METTR-T is a discontinued product. Allegro officially ended production on March 6, 2017, and no new samples or production lots are available. Aetrix Electronics maintains limited legacy stock for existing design continuity, but the A4936METTR-T is not recommended for new designs. Customers should consult Allegro's sales team for migration paths to active alternatives like the STSPIN32F0A or MP6532GQ-Z.
What is the function of the CLD pin on the A4936METTR-T?
The CLD pin on the A4936METTR-T sets the locked-rotor detection timeout using an external capacitor. The A4936METTR-T generates a triangle waveform at CLD, and tlock equals 127 cycles of that waveform - simplified to tlock = CCLD × 20 seconds. For example, a 0.1 µF capacitor yields a 2-second lock timeout. Connecting CLD to GND disables lock detection entirely, which may be used in applications where stall protection is handled externally.
Does the A4936METTR-T support both internal and external PWM control?
Yes, the A4936METTR-T supports dual PWM modes: internal fixed-off-time current regulation (using the SENSE resistor and 200 mV threshold) and external PWM via the PWM input pin. When PWM is high, the selected sink-source pair is enabled; when low, synchronous rectification activates during current decay. Both modes use the same gate drive circuitry and benefit from the A4936METTR-T's 1 µs dead time and 7 V gate drive swing.
How does synchronous rectification work in the A4936METTR-T?
In the A4936METTR-T, synchronous rectification turns on the appropriate low-side MOSFET during current decay instead of allowing current to flow through the high-side MOSFET's lossy body diode. This occurs automatically during both internal PWM off-time and external PWM low periods. By using the MOSFET's low RDS(on) instead of the diode's forward voltage drop, the A4936METTR-T reduces power dissipation significantly - especially at high currents and low speeds - and eliminates the need for external Schottky freewheeling diodes.
What package type does the A4936METTR-T use, and what are its thermal characteristics?
The A4936METTR-T uses a 32-contact QFN package (suffix ET): 5 mm × 5 mm footprint, 0.90 mm nominal height, with an exposed thermal pad. Its thermal resistance is θJA = 32 °C/W on a 4-layer JEDEC-standard PCB and θJP = 2 °C/W to the exposed pad. Successful thermal design requires soldering the pad with ≥6 thermal vias to inner ground planes, as specified in JEDEC JESD51-5, to maintain junction temperature ≤150 °C under full-load conditions.
A4936METTR-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:
- -
- Motor Type - AC, DC:
- Brushless DC (BLDC)
- Function:
- Controller - Commutation, Direction Management
- Output Configuration:
- Pre-Driver - Half Bridge (3)
- Interface:
- PWM
- Technology:
- Power MOSFET
- Step Resolution:
- -
- Applications:
- General Purpose
- Current - Output:
- -
- Voltage - Supply:
- 8.5V ~ 37.5V
- Voltage - Load:
- -
- Operating Temperature:
- -20°C ~ 105°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 32-QFN (5x5)
A4936METTR-T FAQ
1.How can I place an order for A4936METTR-T through Aetrix?
Please submit a Request for Quotation (RFQ) for A4936METTR-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 A4936METTR-T reliable?
The price and inventory of A4936METTR-T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for A4936METTR-T is usually 5 days.
3.What payment methods are accepted for A4936METTR-T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for A4936METTR-T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for A4936METTR-T?
A4936METTR-T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your A4936METTR-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 A4936METTR-T?
For technical support, including A4936METTR-T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your A4936METTR-T requirements.
6.How does Aetrix verify that A4936METTR-T is sourced from the original manufacturer or authorized distributors?
All A4936METTR-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 A4936METTR-T meets industry standards.
7.What is the process for return or replacement of A4936METTR-T?
All A4936METTR-T units undergo pre-shipment inspection (PSI). If there is an issue with A4936METTR-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 A4936METTR-T part is unused and in its original packaging.
Return procedure for A4936METTR-T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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