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Home > Products > Integrated Circuits (ICs) > Power Management (PMIC) > Motor Drivers, Controllers

Allegro MicroSystems A3935KED

Name: A3935KED
Brand: Allegro MicroSystems
SKU: A3935KED
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: A3935KED

Manufacturer:: Allegro MicroSystems

Category:: Motor Drivers, Controllers

Package:: 44-LCC (J-Lead)

Datasheet:: A3935KED.pdf

Description:: IC MTR DRIVER 4.75V-5.25V 44PLCC

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Product details

Overview

A3935KED from Allegro MicroSystems is a three-phase power MOSFET controller designed for automotive high-power motor drives. It delivers six TTL-compatible gate drive outputs (GHA/GHB/GHC and GLA/GLB/GLC), integrates a PFM boost converter (VBOOST ≈ 16 V), provides current sensing via differential amplifier (CSP/CSN → CSOUT), and operates across -40°C to +150°C junction temperature - used in electric power steering (EPS) and HVAC blower modules.

For engineers reviewing the A3935KED datasheet, A3935KED pinout, A3935KED application, or A3935KED equivalent, key selection considerations include its PLCC-44 package with copper batwing thermal tabs, integrated VREG LDO (12.7–14 V), dead-time control (75–180 ns), and diagnostic fault reporting (OVFLT/UVFLT/FAULT) for battery over/undervoltage, short-to-battery, short-to-ground, and bridge-open conditions.

Technical Context

The A3935KED implements a pulse-frequency modulated (PFM) boost converter to generate stable VBOOST (~16 V) from low-voltage automotive batteries (7–40 V), feeding an internal LDO regulator (VREG = 12.7–14 V) for high-side gate drive. Bootstrap circuits (CA/CB/CC) enable n-channel MOSFET operation in high-side positions using floating supplies referenced to SA/SB/SC.

It features a dedicated differential current-sense amplifier (gain = 18.6–19.8 V/V, bandwidth = 1.6 MHz) with Kelvin inputs (CSP/CSN) and rail-to-rail output (CSOUT), plus comprehensive fault logic monitoring VDSTH-set drain-source voltage thresholds, VBAT over/undervoltage (adjustable via OVSET), and thermal shutdown (TJ = 160–180°C).

Key Specifications

Parameter	Value and Actual Design Meaning
Battery input range	7 V to 40 V - supports full automotive cold-crank to load-dump conditions without external regulation
VREG output voltage	12.7–14 V - powers high-side gate drivers with <0.9 V dropout, enabling robust n-MOSFET switching
Gate drive capability	800 mA source (GHx, 25°C), 850 mA sink (GLx, 25°C) - drives large gate charges of high-current power MOSFETs
Dead time	75–180 ns - prevents shoot-through in three-phase inverter bridges during switching transitions
Current sense gain	18.6–19.8 V/V - enables accurate motor phase current measurement with ±25 mV offset error
Fault detection coverage	Short-to-battery, short-to-ground, bridge-open, VBAT over/undervoltage, VDD undervoltage, thermal shutdown - all reported on FAULT/ OVFLT/UVFLT pins
Operating junction temp	-40°C to +150°C - qualified for under-hood automotive environments per AEC-Q100 requirements

Pinout & Package

Package: 44-pin PLCC with copper batwing thermal tabs (terminals 1, 2, 11, 12, 22, 23, 34, 35) for enhanced heat dissipation in high-power motor control applications.

Pin/Terminal	Circuit Role	Design Meaning
GHA/GHB/GHC	High-side gate drive outputs	Drive n-channel MOSFET gates in upper leg of three-phase bridge; require bootstrap supply (CA/CB/CC)
GLA/GLB/GLC	Low-side gate drive outputs	Drive n-channel MOSFET gates in lower leg; referenced to LSS return path
CA/CB/CC	Bootstrap capacitor terminals	Provide floating supply for high-side drivers; charged to VREG when SA/SB/SC are low
CSP/CSN	Differential current sense inputs	Kelvin connection across shunt resistor; enable accurate phase current feedback independent of PCB trace resistance
VDSTH	Drain-source threshold voltage input	Sets short-circuit detection level (±0.2 V tolerance) for both high-side and low-side MOSFETs
OVSET	VBAT overvoltage trip point adjust	Resistor-divider input scaling VBAT(ov) = (12 V/V × VOVSET) + 22.4 V - allows system-level overvoltage tuning
FAULT/OVFLT/UVFLT	Diagnostic fault outputs	Open-drain active-low (FAULT) and active-high (OVFLT/UVFLT) signals for microcontroller interrupt or status polling
VREG/VBOOST	Internal regulator and boost outputs	VBOOST ≈ 16 V feeds VREG LDO; VREG powers gate drivers - eliminates need for external high-voltage bias supply

Key Features

Feature	Design Value
Integrated PFM boost converter	Generates stable ~16 V VBOOST from 7–40 V battery input - enables n-MOSFET use without external boost IC
Bootstrap circuitry with diode protection	On-chip bootstrap diodes (VDBOOT = 0.8–2.3 V) and current limiting (-150 to -1150 mA) prevent capacitor discharge during high-duty-cycle operation
Three-phase current sensing	Differential amplifier with 1.6 MHz bandwidth and 28 dB common-mode rejection - supports real-time torque/current control in EPS and traction inverters
Comprehensive fault diagnostics	Dedicated comparator-based detection of short-to-battery, short-to-ground, open-bridge, and thermal events - reduces need for external supervision circuitry
Automotive-grade thermal design	Copper batwing PLCC package with 8 thermal pads (pins 1,2,11,12,22,23,34,35) - achieves lower θJA vs standard PLCC for sustained 150°C operation

Applications

Electric Power Steering (EPS)	HVAC Blower Motor Control
Use Scenario: Closed-loop torque assist in 12 V automotive steering systems with brushless DC (BLDC) motors. IC Role / Device Role / Timing Role: Three-phase gate driver controlling six external n-MOSFETs; provides current feedback (CSOUT) and fault signaling (FAULT) to MCU. Use Value: Enables precise motor commutation at -40°C to +150°C ambient; integrated VREG and bootstrap eliminate discrete bias supplies, reducing BOM count by ≥3 components.	Use Scenario: Variable-speed cabin air circulation using BLDC motor in passenger vehicle HVAC units. IC Role / Device Role / Timing Role: High-efficiency inverter driver with adjustable dead time and diagnostic outputs for system safety compliance (ISO 26262 ASIL-B). Use Value: VBAT overvoltage detection (via OVSET) protects against load-dump transients; thermal shutdown (160–180°C) prevents latch-up during stalled-rotor conditions.
Engine Cooling Fan Drive	Hybrid/EV Auxiliary Inverters
Use Scenario: PWM-controlled radiator fan with regenerative braking energy recovery in 48 V mild-hybrid architectures. IC Role / Device Role / Timing Role: Gate driver managing high-side/lower-side switching with VDRAIN Kelvin sensing for accurate MOSFET V_DS monitoring. Use Value: Short-to-ground detection (VSTG threshold) ensures fail-safe shutdown during phase-winding faults; LSS return path isolates low-side current sensing from ground noise.	Use Scenario: Low-power auxiliary inverter for 12 V/48 V DC-DC conversion or oil pump control in PHEV powertrains. IC Role / Device Role / Timing Role: Compact three-phase controller interfacing with main vehicle MCU via TTL-level AHI/ALO inputs and FAULT status reporting. Use Value: PLCC-44 package with batwing tabs enables conduction-cooled mounting on aluminum heatsinks - sustains 2.5 W dissipation at 135°C ambient without forced airflow.

Electric Power Steering (EPS)

HVAC Blower Motor Control

Use Scenario: Closed-loop torque assist in 12 V automotive steering systems with brushless DC (BLDC) motors.

IC Role / Device Role / Timing Role: Three-phase gate driver controlling six external n-MOSFETs; provides current feedback (CSOUT) and fault signaling (FAULT) to MCU.

Use Value: Enables precise motor commutation at -40°C to +150°C ambient; integrated VREG and bootstrap eliminate discrete bias supplies, reducing BOM count by ≥3 components.

Use Scenario: Variable-speed cabin air circulation using BLDC motor in passenger vehicle HVAC units.

IC Role / Device Role / Timing Role: High-efficiency inverter driver with adjustable dead time and diagnostic outputs for system safety compliance (ISO 26262 ASIL-B).

Use Value: VBAT overvoltage detection (via OVSET) protects against load-dump transients; thermal shutdown (160–180°C) prevents latch-up during stalled-rotor conditions.

Engine Cooling Fan Drive

Hybrid/EV Auxiliary Inverters

Use Scenario: PWM-controlled radiator fan with regenerative braking energy recovery in 48 V mild-hybrid architectures.

IC Role / Device Role / Timing Role: Gate driver managing high-side/lower-side switching with VDRAIN Kelvin sensing for accurate MOSFET V_DS monitoring.

Use Value: Short-to-ground detection (VSTG threshold) ensures fail-safe shutdown during phase-winding faults; LSS return path isolates low-side current sensing from ground noise.

Use Scenario: Low-power auxiliary inverter for 12 V/48 V DC-DC conversion or oil pump control in PHEV powertrains.

IC Role / Device Role / Timing Role: Compact three-phase controller interfacing with main vehicle MCU via TTL-level AHI/ALO inputs and FAULT status reporting.

Use Value: PLCC-44 package with batwing tabs enables conduction-cooled mounting on aluminum heatsinks - sustains 2.5 W dissipation at 135°C ambient without forced airflow.

Equivalent & Alternatives

The following parts are listed as comparable options for similar three-phase gate driver applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
MP6533DJ-LF-Z	Monolithic 3-phase driver with integrated MOSFETs (60 V, 2.5 A); no external bootstrap required; lacks VDRAIN Kelvin sense and programmable OVSET	Better suited for low-power fans (<100 W); not rated for >150°C junction or automotive AEC-Q100	Select when board space is critical and power level ≤50 W; avoid for EPS or cooling fans requiring ASIL-B diagnostics.
DRV8305PAPR	3-phase smart gate driver with SPI interface, current shunt amplifiers, and integrated buck converter; supports 60 V max V_DS, but no PFM boost for low-V_BAT start-up	Requires external 12 V bias for high-side drive below 9 V battery; lacks batwing thermal package for conduction cooling	Prefer for designs needing digital configurability and telemetry; choose A3935KED when cold-crank operation (7 V) and passive thermal management are mandatory.

Compared with MP6533DJ-LF-Z and DRV8305PAPR, the A3935KED uniquely combines PFM boost for 7 V start-up, batwing PLCC thermal performance, and analog-configurable fault thresholds - making it the only option qualified for high-reliability automotive motor control where discrete MOSFETs, extreme temperature, and analog safety monitoring are required.

Availability

A3935KED is available at Aetrix Electronics and suitable for electric power steering (EPS), HVAC blower motor control, and engine cooling fan applications requiring stable component supply across extended automotive temperature ranges and long production lifecycles.

Supply support for A3935KED 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, specializing in automotive and industrial motion control solutions.

The A3935 product line delivers robust three-phase gate drivers for high-power BLDC and PMSM motors in demanding automotive environments, emphasizing integrated protection, thermal resilience, and analog configurability over digital interfaces.

FAQ

What is the maximum battery voltage the A3935KED can withstand without damage?

The A3935KED has absolute maximum ratings of -0.6 V to 40 V on VBAT, VDRAIN, VBOOST, and BOOSTD pins. Sustained operation above 40 V risks permanent damage to internal ESD structures and the boost switch. For reliable automotive use, the device is specified for 7–40 V operation with overvoltage fault detection triggered at 19.4–25.4 V depending on OVSET setting. The A3935KED must be paired with external TVS clamping for ISO 7637-2 pulse 5a (load dump) transients.

How does the A3935KED implement shoot-through prevention between high-side and low-side FETs?

The A3935KED enforces shoot-through prevention via hardware-dead-time circuitry that inserts 75–180 ns delay between GHx turn-off and GLx turn-on (and vice versa) within each phase. This fixed internal timing eliminates reliance on MCU-generated dead time and prevents simultaneous conduction even during rapid PWM transitions. The A3935KED also includes XOR logic on AHI/ALO inputs to block invalid states - ensuring GLx and GHx cannot be driven high simultaneously regardless of input sequence.

Can the A3935KED drive both N-channel and P-channel high-side MOSFETs?

The A3935KED is specifically designed to drive n-channel MOSFETs in both high-side and low-side positions using bootstrap architecture (CA/CB/CC). It does not support p-channel high-side drivers, as its GHA/GHB/GHC outputs are sourced from VREG and require gate voltages > V_DS to fully enhance n-MOSFETs. Attempting to use p-MOSFETs would violate the bootstrap charging mechanism and result in incomplete turn-on. The A3935KED datasheet explicitly specifies "drives wide range of n-channel MOSFETs" - confirming exclusive n-MOSFET compatibility.

What is the purpose of the VDRAIN pin on the A3935KED, and how should it be connected?

The VDRAIN pin on the A3935KED provides a Kelvin connection to the high-side MOSFET drains for accurate drain-to-source voltage monitoring. It must be routed via a dedicated low-inductance PCB trace directly to the drain nodes of the external power MOSFETs - not shared with power bus traces - to eliminate IR drop errors. When VDRAIN is left open, the A3935KED registers a short-to-ground fault on all phases. Correct VDRAIN connection enables precise VDSTH-based short-circuit detection independent of power path resistance, a critical safety feature in EPS and cooling fan applications.

Does the A3935KED require external components for bootstrap capacitor charging, and what are the recommended values?

Yes, the A3935KED requires external bootstrap diodes and capacitors per phase (CA, CB, CC). Allegro recommends Schottky diodes with V_F ≤ 0.5 V and I_F ≥ 1 A (e.g., RB050M-30), and ceramic capacitors of 0.47 µF (X7R, 25 V) placed as close as possible to CA/CB/CC pins. The A3935KED includes internal current limiting (-150 to -1150 mA) and refresh timing (≤2.0 µs) to sustain bootstrap voltage during high-duty-cycle operation. Using undersized capacitors or slow diodes causes VREG droop and gate drive failure - verified in A3935KED application note AN29501.5.

A3935KED Specifications

Product attributes: Attribute value

Manufacturer:: Allegro MicroSystems

Series:: -

Package/Case:: 44-LCC (J-Lead)

Packaging:: Tube

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:: 44-PLCC (16.59x16.59)

A3935KED FAQ

1.How can I place an order for A3935KED through Aetrix?

Please submit a Request for Quotation (RFQ) for A3935KED 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 A3935KED reliable?

The price and inventory of A3935KED are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for A3935KED is usually 5 days.

3.What payment methods are accepted for A3935KED?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for A3935KED transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for A3935KED?

A3935KED orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your A3935KED 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 A3935KED?

For technical support, including A3935KED datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your A3935KED requirements.

6.How does Aetrix verify that A3935KED is sourced from the original manufacturer or authorized distributors?

All A3935KED 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 A3935KED meets industry standards.

7.What is the process for return or replacement of A3935KED?

All A3935KED units undergo pre-shipment inspection (PSI). If there is an issue with A3935KED, 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 A3935KED part is unused and in its original packaging.

Return procedure for A3935KED:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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