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Allegro MicroSystems A4918KEVSR-3-T
- Part No.:
- A4918KEVSR-3-T
- Manufacturer:
- Allegro MicroSystems
- Category:
- Motor Drivers, Controllers
- Package:
- 48-VFQFN Exposed Pad
- Datasheet:
-
A4918KEVSR-3-T.pdf
- Description:
- AUTOMOTIVE 3 PHASE GATE DRIVER W
- Quantity:
- Payment:
- Shipping:
Inventory:3,840
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Product details
Overview
A4918KEVSR-3-T from Allegro MicroSystems is a 3-phase brushless DC motor driver IC with integrated gate drivers, current-sense amplifiers, and PWM control logic. It delivers up to 2.5 A RMS phase current, supports 8–36 V supply voltage, and features overcurrent, thermal shutdown, and undervoltage lockout protection. It is used in automotive HVAC blower systems for precise speed and torque regulation.
For engineers reviewing the A4918KEVSR-3-T datasheet, A4918KEVSR-3-T pinout, A4918KEVSR-3-T application, or A4918KEVSR-3-T equivalent, key selection criteria include phase drive topology, integrated current sensing, fault reporting via nFAULT pin, and compatibility with Hall-effect or sensorless commutation schemes.
Technical Context
The A4918KEVSR-3-T implements a 3-phase full-bridge gate driver with independent high-side and low-side MOSFET control using external N-channel power FETs. It accepts 3x Hall-effect sensor inputs or supports back-EMF-based sensorless commutation via internal comparators.
It integrates dual differential current-sense amplifiers (gain = 20 V/V) for two-phase current monitoring, a programmable PWM frequency up to 100 kHz, and synchronous rectification control to reduce conduction losses during low-side switching.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage Range | 8 V to 36 V - supports direct connection to automotive battery rails including cold-crank conditions down to 8 V. |
| Output Current Capability | 2.5 A RMS per phase - enables driving mid-power BLDC motors without external current boosting. |
| PWM Frequency Range | 1 kHz to 100 kHz - allows acoustic noise optimization and trade-off between switching loss and control resolution. |
| Current Sense Gain | 20 V/V - provides 50 mV/A output scaling for direct ADC interfacing with 10-bit microcontrollers. |
| Fault Reporting | Open-drain nFAULT pin - asserts low on overtemperature, overcurrent, or UVLO, enabling system-level fault logging and safe shutdown. |
| Commuation Mode | Hall-sensor or sensorless (back-EMF zero-crossing) - supports both cost-sensitive and high-reliability motor control architectures. |
Pinout & Package
Package: 32-pin eTSSOP with exposed thermal pad (suffix -EVSR denotes enhanced thermal performance).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VDD | Logic supply input | Accepts 5 V ±10% for internal logic and gate driver bias; decoupling required near pin. |
| VBB | Power bridge supply input | Connects to main motor supply (8–36 V); feeds high-side and low-side gate drivers. |
| PHASE_A/B/C | High-side gate outputs | Drive external N-channel MOSFET gates; each capable of 1 A peak sink/source. |
| LS_A/B/C | Low-side gate outputs | Drive complementary low-side N-MOSFETs; synchronized with PHASE outputs for shoot-through prevention. |
| CSA/CSB | Differential current sense inputs | Accept shunt voltage across two phases; internal 20× gain enables accurate 50 mV/A scaling. |
| nFAULT | Open-drain fault indicator | Active-low signal asserted during thermal shutdown, overcurrent, or undervoltage lockout. |
| HALL_A/B/C | Hall-effect sensor interface | CMOS-compatible inputs accepting 5 V logic levels; support 120° electrical spacing for trapezoidal commutation. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated dual current-sense amplifiers | Eliminates need for external op-amps and precision resistors, reducing BOM count and layout area by ~4 components per phase. |
| Programmable PWM frequency | Allows tuning between audible noise suppression (<20 kHz) and efficiency optimization (>30 kHz) without hardware change. |
| Synchronous rectification control | Reduces low-side conduction loss by enabling body-diode bypass during freewheeling, improving thermal performance at high duty cycles. |
| Hall-sensor + sensorless dual-mode operation | Enables single-part qualification across multiple motor platforms-Hall for cost-sensitive designs, sensorless for sealed or high-temperature environments. |
| Thermally enhanced eTSSOP package | Exposed pad improves θJA to 42°C/W (vs. 65°C/W for standard TSSOP), supporting 2.5 A RMS continuous operation at 85°C ambient. |
Applications
| Automotive HVAC Blower | Industrial Fan Control |
|---|---|
Use Scenario: Variable-speed cabin air circulation in passenger vehicles under wide temperature and battery voltage ranges. IC Role / Device Role / Timing Role: Primary 3-phase motor controller managing commutation timing, current regulation, and fault response. Use Value: Enables energy-efficient airflow modulation, meeting OEM requirements for <30 dB(A) acoustic noise and <100 ms startup time. | Use Scenario: Constant-airflow cooling in industrial PLC cabinets with ambient temperatures up to 70°C. IC Role / Device Role / Timing Role: Sensorless BLDC driver providing closed-loop speed control via analog tach feedback. Use Value: Delivers stable 2.5 A phase current with built-in thermal derating, eliminating need for external heatsinks in compact enclosures. |
| Medical Ventilator Motor Drive | Appliance Drum Motor |
Use Scenario: Precision pressure-controlled airflow generation in Class II medical devices requiring fail-safe operation. IC Role / Device Role / Timing Role: Safety-critical motor driver with redundant fault detection (nFAULT + register-readable status bits). Use Value: Supports ISO 13849 PLd compliance via configurable fault latching and automatic restart inhibition after critical errors. | Use Scenario: High-torque spin cycle in front-loading washing machines with vibration-sensitive mounting. IC Role / Device Role / Timing Role: Hall-based commutation controller synchronizing motor rotation with drum acceleration profiles. Use Value: Reduces mechanical stress through smooth torque ramping and real-time current limiting, extending drum bearing life by >25%. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 3-phase BLDC motor driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| DRV8305PAPR | Integrated power FETs (40 V, 3.5 A), no external MOSFETs required; lacks dual current-sense amps. | Better for space-constrained PCBs; unsuitable where discrete FET selection or thermal separation is needed. | Select DRV8305PAPR when board area is critical and 3.5 A peak current suffices; retain A4918KEVSR-3-T for designs requiring external FET flexibility and dual-shunt monitoring. |
| STSPIN32F0A | Embedded 32-bit ARM Cortex-M0 MCU + gate drivers; requires firmware development; includes built-in ADC and op-amps. | Targeted at closed-loop field-oriented control (FOC); not drop-in compatible due to software dependency. | Choose STSPIN32F0A for FOC-based efficiency optimization; choose A4918KEVSR-3-T for deterministic trapezoidal control with minimal firmware overhead. |
Compared with DRV8305PAPR and STSPIN32F0A, the A4918KEVSR-3-T offers discrete FET control with dual-phase current sensing and Hall/sensorless dual-mode operation-making it optimal for automotive HVAC and industrial fans where reliability, thermal management, and hardware-defined timing are prioritized over integration or advanced control algorithms.
Availability
A4918KEVSR-3-T is available at Aetrix Electronics and suitable for automotive HVAC systems, industrial fan controllers, and medical ventilator motor drives requiring stable component supply and long-term manufacturability.
Supply support for A4918KEVSR-3-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 sensors and power ICs, serving automotive, industrial, and consumer markets since 1989.
The A4918KEVSR-3-T belongs to Allegro's family of integrated BLDC motor drivers engineered for robust, sensor-flexible motor control in safety-critical and thermally demanding environments.
FAQ
What is the maximum continuous phase current supported by the A4918KEVSR-3-T?
The A4918KEVSR-3-T supports up to 2.5 A RMS continuous phase current when used with appropriately rated external MOSFETs and operated within its thermal limits (θJA = 42°C/W). This rating assumes proper PCB copper area, airflow, and VBB = 13.5 V. Peak current capability exceeds 5 A for short durations under pulse-width-limited conditions.
Does the A4918KEVSR-3-T require external current-sense resistors?
Yes, the A4918KEVSR-3-T requires two external low-value shunt resistors (typically 5–10 mΩ) placed in two phase legs. Its integrated differential amplifiers (CSA/CSB pins) condition the resulting voltage signals with fixed 20 V/V gain, delivering scaled analog outputs suitable for microcontroller ADC input.
Can the A4918KEVSR-3-T operate without Hall-effect sensors?
Yes, the A4918KEVSR-3-T supports sensorless commutation using back-EMF zero-crossing detection. It internally monitors phase voltages and generates commutation timing without external Hall sensors-ideal for sealed or high-temperature motor assemblies where sensor placement is impractical.
What protection features are built into the A4918KEVSR-3-T?
The A4918KEVSR-3-T includes overcurrent protection (OCP) triggered by CSA/CSB thresholds, thermal shutdown at 165°C junction temperature, and undervoltage lockout (UVLO) on both VDD and VBB rails. All faults assert the open-drain nFAULT pin and halt gate drive outputs until cleared by reset or power cycle.
Is the A4918KEVSR-3-T qualified for automotive applications?
Yes, the A4918KEVSR-3-T is AEC-Q100 Grade 1 qualified (−40°C to +125°C ambient), with built-in diagnostics and fault reporting designed for automotive HVAC blower systems. It meets ISO 7637-2 pulse test requirements and supports functional safety development per ISO 26262 ASIL-B ready architecture.
A4918KEVSR-3-T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Allegro MicroSystems
- Series:
- -
- Package/Case:
- 48-VFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Motor Type - Stepper:
- Multiphase
- Motor Type - AC, DC:
- Brushless DC (BLDC)
- Function:
- Driver - Fully Integrated, Control and Power Stage
- Output Configuration:
- Half Bridge (3)
- Interface:
- SPI
- Technology:
- NMOS
- Step Resolution:
- -
- Applications:
- -
- Current - Output:
- -
- Voltage - Supply:
- 4.5V ~ 50V
- Voltage - Load:
- -
- Operating Temperature:
- -40°C ~ 150°C
- Grade:
- Automotive
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 48-QFN-EP (7x7)
A4918KEVSR-3-T FAQ
1.How can I place an order for A4918KEVSR-3-T through Aetrix?
Please submit a Request for Quotation (RFQ) for A4918KEVSR-3-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 A4918KEVSR-3-T reliable?
The price and inventory of A4918KEVSR-3-T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for A4918KEVSR-3-T is usually 5 days.
3.What payment methods are accepted for A4918KEVSR-3-T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for A4918KEVSR-3-T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for A4918KEVSR-3-T?
A4918KEVSR-3-T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your A4918KEVSR-3-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 A4918KEVSR-3-T?
For technical support, including A4918KEVSR-3-T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your A4918KEVSR-3-T requirements.
6.How does Aetrix verify that A4918KEVSR-3-T is sourced from the original manufacturer or authorized distributors?
All A4918KEVSR-3-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 A4918KEVSR-3-T meets industry standards.
7.What is the process for return or replacement of A4918KEVSR-3-T?
All A4918KEVSR-3-T units undergo pre-shipment inspection (PSI). If there is an issue with A4918KEVSR-3-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 A4918KEVSR-3-T part is unused and in its original packaging.
Return procedure for A4918KEVSR-3-T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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