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Allegro MicroSystems A3935KLQTR-T
- Part No.:
- A3935KLQTR-T
- Manufacturer:
- Allegro MicroSystems
- Category:
- Motor Drivers, Controllers
- Package:
- 36-BSOP (0.295", 7.50mm Width)
- Datasheet:
-
A3935KLQTR-T.pdf
- Description:
- IC MOTOR DRVR 4.75V-5.25V 36QSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,401
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Product details
Overview
A3935KLQTR-T from Allegro MicroSystems is a 3-phase N-channel MOSFET gate driver IC designed for automotive high-power motor control. It integrates a PFM boost converter (16 V nominal), internal LDO regulator (VREG = 13.5 V), six TTL-compatible gate drive outputs, differential current sensing (gain = 19.2 V/V), and comprehensive fault protection including short-to-battery/ground, bridge-open, and thermal shutdown. It operates across –40°C to 150°C junction temperature in electric power steering and HVAC blower systems.
For engineers reviewing the A3935KLQTR-T datasheet, A3935KLQTR-T pinout, A3935KLQTR-T application, or A3935KLQTR-T equivalent, key selection considerations include its 36-pin QSOP package, bootstrap-based high-side drive architecture, adjustable VBAT overvoltage threshold (19.4–40 V), integrated drain-source voltage monitoring via VDSTH/VDRAIN, and AEC-Q100 qualified operation for under-hood environments.
Technical Context
The A3935KLQTR-T implements a dedicated 3-phase gate driver architecture with independent high-side (GHA/GHB/GHC) and low-side (GLA/GLB/GLC) outputs, each controlled by TTL-compatible inputs (AHI/ALO, etc.). Its PFM boost converter maintains stable VBOOST (~16 V) across 7–40 V battery input, enabling robust N-MOSFET drive even during cold-crank conditions.
Fault detection is hardware-automated: motor lead shorts are identified via Kelvin-connected VDRAIN and LSS with programmable VDSTH threshold (0.5–3.0 V); current sensing uses CSP/CSN differential inputs with 1.6 MHz bandwidth and ±200 mV common-mode range; diagnostic outputs (FAULT, OVFLT, UVFLT) provide real-time status with hysteresis for noise immunity.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Battery Input Range | 7.0 V to 40 V - supports full automotive battery range including cold-crank (6.5 V typical minimum) and load-dump transients. |
| VREG Output Voltage | 12.7 V to 14.0 V - regulated high-side gate supply enabling reliable N-MOSFET turn-on with >10 V VGS margin. |
| Gate Drive Current | 800 mA source (GHx, 25°C), 850 mA sink (GLx, 25°C) - sufficient to drive large gate charges of automotive-grade MOSFETs at high PWM frequencies. |
| Current Sense Gain | 18.6–19.8 V/V - precise proportional output (CSOUT) for shunt-based phase current measurement with <±25 mV DC error. |
| Thermal Shutdown | 160°C to 180°C activation - protects device and external FETs during overload or poor heatsinking; 7–13°C hysteresis prevents oscillation. |
| Dead Time | 75 ns to 180 ns - hardware-enforced shoot-through prevention between complementary high/low-side drivers per phase. |
| ESD Rating | 2.5 kV HBM, 1.05 kV CDM - meets AEC-Q100-002/-011 for robustness in automotive assembly and field operation. |
Pinout & Package
Package: 36-pin QSOP (LQ), 0.8 mm pitch, surface-mount, Pb-free (100% matte tin plating), JEDEC-compliant footprint (SOP80P1033X264-36M reference).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 CSP | Current-sense amplifier non-inverting input | Kelvin connection to high-side of shunt resistor; enables accurate low-side current sensing with 80 kΩ input impedance. |
| 2 VDSTH | Drain-source voltage monitor threshold | Analog input (0.5–3.0 V) setting fault trip point for short-to-battery/ground detection on all three phases. |
| 3 LSS | Low-side gate driver return | Common source node for GLA/GLB/GLC; referenced for CSN and short-to-ground fault detection. |
| 4–6 GLC, SC, GHC | Low-side gate drive / motor phase C / high-side gate drive | Direct drive path for phase-C bridge leg; SC connects to motor winding; GHC drives high-side N-MOSFET gate via bootstrap capacitor CC. |
| 7–16 CC, GLB, SB, GHB, CB, GLA, SA, GHA, CA, VREG | Bootstrap supply / low/high-side drive / motor phase / gate supply | Per-phase bootstrap network (CA/CB/CC) supplies floating VREG-derived voltage to GHC/GHB/GHA; VREG = 13.5 V regulated output. |
| 17 VDRAIN | Kelvin drain monitor input | High-impedance connection to high-side MOSFET drains; eliminates PCB trace IR drop for accurate VDS monitoring during fault detection. |
| 18–21 VBOOST, BOOSTS, BOOSTD, GND | Boost converter output / switch source/drain / ground | VBOOST powers VREG LDO; BOOSTD/BOOSTS interface external inductor/diode; GND is common return for VDD and VBAT supplies. |
| 22–25 VBAT, UVFLT, OVFLT, FAULT | Battery input / undervoltage/overvoltage fault flags / primary fault output | VBAT powers internal circuits; UVFLT/OVFLT are open-drain status flags; FAULT is active-low, asserted on any critical fault condition. |
| 26–32 ALO, AHI, BHI, BLO, CLO, CHI, ENABLE | TTL-compatible gate control inputs | Direct logic-level control of all six gate drivers; ENABLE globally disables outputs for coasting or safety shutdown. |
| 33–36 OVSET, CSOUT, VDD, CSN | Overvoltage setpoint / current sense output / logic supply / sense inverting input | OVSET sets VBAT overvoltage threshold via resistor divider; CSOUT provides amplified shunt voltage (0.075–VDD–0.25 V range); VDD = 4.75–5.25 V logic rail; CSN completes differential sense pair. |
Key Features
| Feature | Design Value |
|---|---|
| Pulse-frequency modulated (PFM) boost converter | Maintains stable ~16 V VBOOST across 7–40 V battery input, eliminating need for external boost IC in 12 V/24 V automotive systems. |
| Integrated differential current-sense amplifier | 19.2 V/V gain, 1.6 MHz bandwidth, and ±200 mV input common-mode range enable precise, high-speed phase current feedback without external op-amps. |
| Hardware-based motor lead fault detection | Detects short-to-battery, short-to-ground, and bridge-open faults using Kelvin-connected VDRAIN/LSS and programmable VDSTH threshold-no MCU intervention required. |
| Adjustable VBAT overvoltage protection | Settable trip point (19.4–40 V) via OVSET pin with 9–15% hysteresis, allowing customization for different vehicle electrical architectures. |
| Thermal shutdown with hysteresis | Activates at 160–180°C junction temperature and holds off until temperature drops 7–13°C, preventing thermal cycling during transient overloads. |
Applications
| Electric Power Steering (EPS) | HVAC Blower Motor Control |
|---|---|
Use Scenario: Driving three-phase brushless DC motor in column-assist or rack-assist EPS modules requiring high torque at low speed and fail-safe operation. IC Role / Device Role / Timing Role: Primary gate driver controlling N-channel MOSFET half-bridges; provides real-time current sensing and motor lead fault detection for ASIL-B compliance. Use Value: Enables compact, efficient motor control with integrated diagnostics-reducing external component count and improving system-level functional safety response time. | Use Scenario: Controlling cabin air blower motor in automotive HVAC systems where variable speed, quiet operation, and thermal robustness are critical. IC Role / Device Role / Timing Role: 3-phase gate driver with bootstrap high-side drive and differential current monitoring; manages PWM switching up to 22.5 kHz with dead-time control. Use Value: Delivers smooth, low-noise airflow control while maintaining operation during battery voltage dips (e.g., engine start) via integrated PFM boost converter. |
| Engine Cooling Fan Control | Hybrid/EV Auxiliary Pump Drive |
Use Scenario: Regulating radiator cooling fan speed based on coolant temperature and vehicle speed in ICE and hybrid vehicles. IC Role / Device Role / Timing Role: High-current gate driver interfacing with discrete N-MOSFETs; monitors phase current for stall detection and thermal derating. Use Value: Supports wide input voltage range (7–40 V) and high ambient temperature (135°C ambient, 150°C junction), ensuring reliability in under-hood environments. | Use Scenario: Driving oil or coolant pumps in 48 V mild-hybrid or high-voltage EV auxiliary systems requiring functional safety and fault logging. IC Role / Device Role / Timing Role: Fault-aware motor controller providing VDRAIN-based open-load detection and CSOUT-based current telemetry for pump health monitoring. Use Value: Integrates critical diagnostics (short-to-battery, short-to-ground, bridge-open) into single IC-reducing BOM cost and simplifying ISO 26262 diagnostic coverage analysis. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 3-phase gate driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MP6532GQ-Z | 60 V max VDD, integrated current sense, no PFM boost; requires external 12 V gate supply. | Lacks integrated boost converter and Kelvin VDRAIN monitoring; suited for 12 V-only systems with external regulation. | Select when board space allows external boost and thermal constraints permit lower integration. |
| DRV8303DCA | 40 V max VM, integrated buck regulator (not PFM), 10-bit current DAC, SPI interface. | Offers digital configuration and diagnostics but no hardware VDRAIN fault detection; higher software overhead. | Prefer when programmability and telemetry outweigh need for autonomous analog fault response. |
Compared with MP6532GQ-Z and DRV8303DCA, the A3935KLQTR-T delivers unique hardware-based motor lead fault detection via VDRAIN/Kelvin sensing and a PFM boost converter optimized for wide-input automotive batteries-enabling simpler, more robust designs in safety-critical EPS and cooling applications without MCU dependency for basic fault handling.
Availability
A3935KLQTR-T is available at Aetrix Electronics and suitable for electric power steering, HVAC blower control, and engine cooling fan applications requiring stable component supply across extended automotive temperature ranges and long product lifecycles.
Supply support for A3935KLQTR-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 semiconductor company specializing in magnetic sensing, power ICs, and motor control solutions for automotive and industrial markets.
The A3935KLQTR-T belongs to Allegro's automotive-grade 3-phase gate driver product line, engineered specifically for high-reliability motor control in electric power steering, HVAC, and cooling systems under harsh under-hood conditions.
FAQ
What is the maximum operating junction temperature of the A3935KLQTR-T?
The A3935KLQTR-T has a maximum junction temperature (TJ) rating of 150°C under normal operation, with thermal shutdown activating at 160–180°C to protect the device and external MOSFETs. The thermal shutdown hysteresis is 7–13°C, ensuring stable recovery after fault removal. This specification enables reliable use in under-hood automotive applications where ambient temperatures reach 135°C.
Does the A3935KLQTR-T require an external boost converter?
No, the A3935KLQTR-T integrates a pulse-frequency modulated (PFM) boost converter that generates a stable ~16 V VBOOST supply from a 7–40 V battery input. This eliminates the need for an external boost IC and enables robust high-side N-MOSFET gate drive during cold-crank conditions. The boost converter includes current limiting, blanking time, and voltage regulation loops fully implemented within the A3935KLQTR-T.
How does the A3935KLQTR-T detect motor lead short-to-ground faults?
The A3935KLQTR-T detects short-to-ground faults by monitoring the voltage between VDRAIN (Kelvin-connected to high-side MOSFET drains) and the corresponding motor phase (SA/SB/SC) when a high-side driver is active. If this voltage exceeds the threshold set by the VDSTH pin (0.5–3.0 V), the FAULT output asserts low. Detection occurs only when GHx is enabled, ensuring accurate timing and avoiding false triggers during inactive states.
What is the function of the CSOUT pin on the A3935KLQTR-T?
The CSOUT pin on the A3935KLQTR-T is the output of the integrated differential current-sense amplifier. It provides a voltage proportional to motor phase current measured across an external shunt resistor (VCSOUT = ILOAD × 19.2 × RSENSE + VOS). With a 0.075–(VDD–0.25) V output range, 1.6 MHz bandwidth, and ±25 mV DC error, CSOUT enables precise, real-time current feedback for closed-loop motor control without external signal conditioning.
Is the A3935KLQTR-T qualified to AEC-Q100 standards?
Yes, the A3935KLQTR-T is qualified to AEC-Q100 Grade 0 (–40°C to +150°C TJ) and includes ESD ratings of 2.5 kV HBM and 1.05 kV CDM per AEC-Q100-002 and -011. Its design incorporates automotive-specific protections-including VBAT over/undervoltage detection, thermal shutdown, and motor lead fault monitoring-making it suitable for safety-critical applications such as electric power steering and HVAC systems.
A3935KLQTR-T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Allegro MicroSystems
- Series:
- -
- Package/Case:
- 36-BSOP (0.295", 7.50mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Motor Type - Stepper:
- -
- Motor Type - AC, DC:
- -
- Function:
- Controller - Commutation, Direction Management
- Output Configuration:
- Pre-Driver - Half Bridge (3)
- Interface:
- Parallel
- Technology:
- Power MOSFET
- Step Resolution:
- -
- Applications:
- -
- Current - Output:
- -
- Voltage - Supply:
- 4.75V ~ 5.25V
- Voltage - Load:
- 7V ~ 40V
- Operating Temperature:
- -40°C ~ 135°C (TA)
- Grade:
- Automotive
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 36-QSOP
A3935KLQTR-T FAQ
1.How can I place an order for A3935KLQTR-T through Aetrix?
Please submit a Request for Quotation (RFQ) for A3935KLQTR-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 A3935KLQTR-T reliable?
The price and inventory of A3935KLQTR-T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for A3935KLQTR-T is usually 5 days.
3.What payment methods are accepted for A3935KLQTR-T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for A3935KLQTR-T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for A3935KLQTR-T?
A3935KLQTR-T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your A3935KLQTR-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 A3935KLQTR-T?
For technical support, including A3935KLQTR-T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your A3935KLQTR-T requirements.
6.How does Aetrix verify that A3935KLQTR-T is sourced from the original manufacturer or authorized distributors?
All A3935KLQTR-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 A3935KLQTR-T meets industry standards.
7.What is the process for return or replacement of A3935KLQTR-T?
All A3935KLQTR-T units undergo pre-shipment inspection (PSI). If there is an issue with A3935KLQTR-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 A3935KLQTR-T part is unused and in its original packaging.
Return procedure for A3935KLQTR-T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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