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Allegro MicroSystems A3924KEVSR-J
- Part No.:
- A3924KEVSR-J
- Manufacturer:
- Allegro MicroSystems
- Category:
- Full Half-Bridge (H Bridge) Drivers
- Package:
- 40-VFQFN Exposed Pad
- Datasheet:
-
A3924KEVSR-J.pdf
- Description:
- AUTOMOTIVE FULL BRIDGE MOSFET DR
- Quantity:
- Payment:
- Shipping:
Inventory:1,706
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Product details
Overview
A3924KEVSR-J from Allegro MicroSystems is an automotive-grade N-channel full-bridge MOSFET driver designed for high-power inductive loads including brushed DC motors, solenoids, and actuators. It operates from 5.5 V to 50 V supply, integrates dual current sense amplifiers (gain = 35 V/V, offset ±1 mV), supports SPI-compatible serial control with programmable dead time (1.25–2.15 µs), and delivers ASIL D safety compliance per ISO 26262 as a safety element out of context.
For engineers reviewing the A3924KEVSR-J datasheet, A3924KEVSR-J pinout, A3924KEVSR-J application, or A3924KEVSR-J equivalent, this page provides verified technical context, validated pin functions for the 40-terminal eQFN package, confirmed diagnostic register access via SPI, and real-world automotive motor control use cases with fault coverage details.
Technical Context
The A3924KEVSR-J implements a dual-phase H-bridge gate driver architecture with independent high-side (GHA/GHB) and low-side (GLA/GLB) outputs, each featuring programmable pull-up/pull-down on-resistance (RDS(on)UP ≤ 11 Ω, RDS(on)DN ≤ 4 Ω at 25°C) and passive pull-down networks (RGHPD/RGLPD ≤ 950 kΩ). Its charge pump regulator maintains VREG output at 7.4–13.8 V across VBB = 5.5–50 V, enabling reliable N-MOSFET operation down to 5.5 V battery input.
Diagnostic capability includes real-time monitoring of VDS overvoltage (thresholds 1.2 V–3.15 V), open-load detection (on-state: 225 mV typ; off-state: 1 V typ), overcurrent (VOCT = 3.0 V typ), and thermal warnings (TJW = 135°C typ). All diagnostics are readable and configurable via a 4-wire SPI interface supporting fault masking, verification sequences, and diagnostic output pulse modulation (DG[1:0] selectable).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VBB Range | 5.5 V to 50 V - enables direct connection to automotive battery rails including cold-crank (5.5 V) and load-dump (50 V) conditions without external regulation. |
| VREG Output | 7.4–13.8 V (programmable) - supplies gate drive voltage for high-side N-MOSFETs via bootstrap circuitry; stable down to VBB = 5.5 V using integrated charge pump. |
| Dead Time | 1.25–2.15 µs (default 1.6 µs) - prevents shoot-through by enforcing minimum off-time between complementary high/low-side switching transitions. |
| Current Sense Gain | 35 V/V (typ), ±2% gain error - provides precise motor phase current measurement with 1 mV input offset for accurate torque and stall detection. |
| ASIL Compliance | ASIL D SEooC per ISO 26262 - certified safety element out of context; supports diagnostic verification, fault injection testing, and safe state activation under system-level safety manager control. |
| Thermal Resistance | RθJA = 23 °C/W (4-layer PCB) - enables high-power operation up to 150°C ambient with minimal derating when mounted on thermally optimized layout. |
| Logic Interface | SPI-compatible 4-wire (SCK/SDI/SDO/STRn) + TTL-compatible direct inputs (HA/HBn/LAn/LB) - supports both microcontroller-controlled and standalone logic-mode operation. |
Pinout & Package
Package: 40-terminal eQFN (6 mm × 6 mm, 1.6 mm height, wettable flank, exposed thermal pad connected to GND).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CA, CB | Phase A/B bootstrap capacitor terminals | Connect external ceramic capacitors (e.g., 100 nF) to sustain high-side gate voltage above VBB during PWM conduction. |
| GHA, GHB | High-side gate drive outputs | Drive N-MOSFET gates with 8 Ω pull-up (25°C) and 2.4 Ω pull-down; include passive pull-down (≤950 kΩ) for fail-safe turn-off. |
| GLA, GLB | Low-side gate drive outputs | Source-referenced outputs driving N-MOSFET sources; support synchronous rectification and active freewheeling control. |
| SA, SB | Motor phase terminals | Direct connection points to brushed DC motor windings; rated for continuous 50 V drain-source voltage and transient overvoltage protection. |
| CSPA/CSMA, CSPB/CSMB | Current sense amplifier inputs | Differential inputs for shunt-based phase current sensing; common-mode range –1 V to 2 V supports bidirectional current measurement. |
| VBRG | High-side drain voltage monitor | Monitors VDS of external high-side MOSFETs to detect short-to-battery faults; threshold programmable from 1.2 V to 3.15 V. |
| DIAG | Programmable diagnostic output | Open-drain output delivering fault pulses (90–110 ms period), temperature analog voltage (1440 mV @ 25°C, –3.92 mV/°C slope), or logic status per DG[1:0] configuration. |
| STRn, SCK, SDI, SDO | SPI serial interface | 4-wire interface for reading diagnostic registers, writing configuration (dead time, VDS thresholds, fault blank times), and executing on-line verification routines. |
| ENABLE, RESETn | System control inputs | ENABLE enables/disables all gate drivers; RESETn forces standby mode and clears fault latches - both tolerate 50 V transients per automotive requirements. |
| AGND, GND, PAD | Analog/digital ground & thermal pad | Separate AGND (pin 8) and GND (pin 7) minimize noise coupling; exposed thermal pad must be soldered to PCB ground plane for thermal and EMI performance. |
Key Features
| Feature | Design Value |
|---|---|
| Bootstrap gate drive with charge pump | Enables full N-MOSFET bridge operation from 5.5 V battery input without external high-voltage supply; eliminates need for P-channel high-side switches. |
| Programmable dead time | Configurable 6-bit dead time (DT[5:0]) allows fine-tuning from 1.25 µs to 2.15 µs to match external MOSFET switching characteristics and prevent shoot-through. |
| Dual integrated current sense amplifiers | Two matched amplifiers (±1 mV offset, 35 V/V gain) provide real-time phase current feedback for closed-loop motor control, stall detection, and overcurrent protection. |
| Comprehensive diagnostic coverage | Detects VDS overvoltage, open-load (on/off-state), overcurrent, bootstrap undervoltage, temperature warning/fault, and logic terminal overvoltage - all configurable and verifiable via SPI. |
| ASIL D safety certification | Delivers ISO 26262-compliant safety mechanisms including diagnostic registers, fault injection test modes, and safe state activation - qualified for safety-critical automotive ECU applications. |
Applications
| Electric Power Steering (EPS) | Automotive HVAC Blower Control |
|---|---|
|
Use Scenario: Driving dual-wound brushed DC motor in column-assist EPS systems requiring precise torque control and fail-safe shutdown. IC Role / Device Role / Timing Role: Full-bridge gate driver controlling motor direction and PWM duty cycle; monitors phase current for torque feedback and detects winding shorts/open circuits. Use Value: Enables ASIL D-compliant motor actuation with <100 ms fault response time, eliminating need for external current sensors and discrete protection ICs. |
Use Scenario: Controlling high-current blower fan in vehicle climate control system with variable speed and reverse airflow capability. IC Role / Device Role / Timing Role: H-bridge driver managing motor polarity and PWM frequency; uses VBRG monitoring to detect fan lock-up or bearing failure via VDS overvoltage. Use Value: Reduces BOM count by integrating gate drive, current sensing, and diagnostics - supports automatic fault logging via SPI for service diagnostics. |
| Transmission Solenoid Actuation | Seat/Mirror Positioning Motors |
|
Use Scenario: Driving 12 V/24 V transmission shift solenoids requiring fast, controlled current ramp-up and hold with overtemperature protection. IC Role / Device Role / Timing Role: High-side/low-side driver with programmable dead time ensuring clean solenoid coil energization; uses CS amplifiers for inductance-based position estimation. Use Value: Guarantees solenoid reliability under cold-crank (5.5 V) and load-dump (50 V) conditions while providing real-time coil health diagnostics. |
Use Scenario: Operating small brushed DC motors in power seats and mirrors with soft-start, stall detection, and end-stop sensing. IC Role / Device Role / Timing Role: Bidirectional H-bridge controller using open-load detection (225 mV on-state threshold) to identify mechanical jamming or gear failure. Use Value: Prevents motor burnout and fuse blowing by halting drive on stall detection - verified via SPI-read diagnostic registers during runtime. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar full-bridge MOSFET driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TLE9201SG | Integrated high-/low-side drivers with embedded current sense (no external shunt required); fixed 1.5 µs dead time; no programmable VDS thresholds. | Limited diagnostic configurability; lacks SPI interface and ASIL D certification - suitable for non-safety-critical body electronics only. | Select when cost-sensitive designs prioritize integration over safety compliance and field-configurable diagnostics. |
| DRV8876N | Single H-bridge with integrated current sense and 1x PWM input; no SPI interface; lower VBB max (40 V); no ASIL rating. | Targeted at low-power accessories (e.g., window lifters); lacks dual-phase monitoring and comprehensive fault verification capability. | Choose for simpler, lower-cost applications where ASIL D and multi-fault diagnostic traceability are not required. |
Compared with TLE9201SG and DRV8876N, the A3924KEVSR-J uniquely combines ASIL D safety certification, fully programmable diagnostics via SPI, dual independent current sense channels, and robust 50 V operation - making it the only option qualified for steering and transmission control systems requiring functional safety validation.
Availability
A3924KEVSR-J is available at Aetrix Electronics and suitable for electric power steering, HVAC blower control, and transmission solenoid actuation requiring stable component supply across automotive production lifecycles.
Supply support for A3924KEVSR-J 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 semiconductor company specializing in magnetic sensing, power ICs, and motor control solutions for automotive and industrial markets.
The A3924 product line delivers high-reliability, safety-certified full-bridge drivers for demanding automotive applications including EPS, transmission control, and active suspension systems.
FAQ
What is the maximum operating voltage for A3924KEVSR-J?
The A3924KEVSR-J supports a VBB supply range of 5.5 V to 50 V, with absolute maximum rating of 50 V. This allows direct connection to automotive battery systems during cold-crank (down to 5.5 V) and load-dump events (up to 50 V), eliminating need for external voltage clamping in most designs. The internal charge pump ensures stable gate drive voltage across this full range.
Does A3924KEVSR-J require external bootstrap capacitors?
Yes, the A3924KEVSR-J requires external ceramic bootstrap capacitors connected to pins CA and CB. These capacitors (typically 100 nF X7R) maintain the high-side gate drive voltage above VBB during PWM conduction. The device includes internal bootstrap diodes with forward voltage of 0.7 V (typ) and current limit of 500 mA (typ), but external capacitance is mandatory for proper high-side N-MOSFET operation.
How is diagnostic data accessed on A3924KEVSR-J?
Diagnostic data on A3924KEVSR-J is accessed via its 4-wire SPI-compatible interface (STRn/SCK/SDI/SDO). Engineers can read status registers containing fault flags (VDS overvoltage, open-load, overcurrent), temperature warnings, and verification results. Configuration registers allow programming of dead time, VDS thresholds, and fault blank times - all documented in the A3924-DS Rev. 9 datasheet sections 37–41.
What safety certification does A3924KEVSR-J hold?
The A3924KEVSR-J is certified as an ASIL D safety element out of context (SEooC) per ISO 26262:2018. This includes hardware-level safety mechanisms (diagnostic registers, fault injection test modes, safe state activation), documentation for integration into ASIL D systems, and verification procedures outlined in the safety manual. It is qualified for use in safety-critical automotive applications including electric power steering and transmission control.
Can A3924KEVSR-J operate with TTL-level logic inputs?
Yes, A3924KEVSR-J accepts TTL-compatible logic inputs on HA, HBn, LAn, LB, RESETn, and ENABLE pins. Input high voltage threshold is 2.0 V (min), input low is 0.8 V (max), and hysteresis is 250–550 mV - ensuring robust noise immunity in automotive environments. Pull-down resistors (50 kΩ typical) on HA/LB/ENABLE and pull-up current sources on HBn/LAn further enhance interface reliability without external components.
A3924KEVSR-J Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Allegro MicroSystems
- Series:
- -
- Package/Case:
- 40-VFQFN Exposed Pad
- Packaging:
- Bulk
- Product Status:
- Obsolete
- Output Configuration:
- Half Bridge (2)
- Applications:
- DC Motors, Solenoids
- Interface:
- SPI
- Load Type:
- Inductive, Capacitive, Resistive
- Technology:
- NMOS
- Rds On (Typ):
- 2.4Ohm LS, 8Ohm HS
- Current - Output / Channel:
- -
- Current - Peak Output:
- -
- Voltage - Supply:
- 5.5V ~ 50V
- Voltage - Load:
- 6V ~ 50V
- Operating Temperature:
- -40°C ~ 150°C (TA)
- Grade:
- -
- Qualification:
- -
- Features:
- Bootstrap Circuit
- Fault Protection:
- Current Limiting, Over Temperature, Shoot Through, Short Circuit
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 40-QFN (6x6)
A3924KEVSR-J FAQ
1.How can I place an order for A3924KEVSR-J through Aetrix?
Please submit a Request for Quotation (RFQ) for A3924KEVSR-J 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 A3924KEVSR-J reliable?
The price and inventory of A3924KEVSR-J are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for A3924KEVSR-J is usually 5 days.
3.What payment methods are accepted for A3924KEVSR-J?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for A3924KEVSR-J transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for A3924KEVSR-J?
A3924KEVSR-J orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your A3924KEVSR-J 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 A3924KEVSR-J?
For technical support, including A3924KEVSR-J datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your A3924KEVSR-J requirements.
6.How does Aetrix verify that A3924KEVSR-J is sourced from the original manufacturer or authorized distributors?
All A3924KEVSR-J 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 A3924KEVSR-J meets industry standards.
7.What is the process for return or replacement of A3924KEVSR-J?
All A3924KEVSR-J units undergo pre-shipment inspection (PSI). If there is an issue with A3924KEVSR-J, 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 A3924KEVSR-J part is unused and in its original packaging.
Return procedure for A3924KEVSR-J:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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