Allegro MicroSystems A3930KJP-T

Overview

A3930KJP-T from Allegro MicroSystems is a 3-phase brushless DC (BLDC) motor controller IC designed for automotive-grade N-channel MOSFET gate drive. It delivers 5.5–50 V supply operation, integrated Hall-effect commutation decoding, synchronous rectification, and programmable dead time (180 ns to 3.3 μs) via RDEAD. It enables cost-effective, high-efficiency motor drives in electric power steering and HVAC blower systems.

For engineers reviewing the A3930KJP-T datasheet, A3930KJP-T pinout, A3930KJP-T application, or A3930KJP-T equivalent, key selection considerations include its Hall-input logic fault response (all-zero H1/H2/H3 = fault indication), bootstrap + charge pump architecture enabling 100% duty cycle high-side drive, and integrated current sense amplifier with 19 V/V gain and ±15 mV comparator offset.

Technical Context

The A3930KJP-T implements fixed-frequency PWM current control using an external RC network (20–50 kHz range) and supports both internal current limiting and external PWM torque control. Its dual charge pump system-main regulator (13 V nominal on VREG) and top-off pump per high-side driver-ensures robust gate drive down to 5.5 V battery input while minimizing power loss through mode switching between voltage-doubling and dropout.

Commutation logic decodes 120°-spaced Hall inputs to sequence six-step BLDC drive, with cross-conduction protection enforced by user-configurable dead time and built-in shoot-through prevention. Diagnostics include short-to-battery/ground detection (±300 mV thresholds), overtemperature flag at 170°C, and undervoltage lockouts for VREG (7.25–8.5 V), V5 (3.65–4.0 V), and bootstrap (59–69% of VREG).

Key Specifications

Pinout & Package

Package: 48-lead LQFP with exposed thermal pad (81 mm² footprint, lead-free, 100% matte tin plating). Thermal pad must be soldered to PCB ground plane for RθJP = 2°C/W junction-to-pad conduction.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 3-phase BLDC controller applications.

Compared with A3930KJP-T, A3931KJP-T offers identical gate drive and protection but trades fault detection for startup flexibility, while MP6532GQ-Z sacrifices Hall autonomy and external FET scalability for monolithic integration - making A3930KJP-T optimal for high-reliability, Hall-based automotive motor control with external power stage optimization.

Availability

A3930KJP-T is available at Aetrix Electronics and suitable for electric power steering, HVAC blower, and engine cooling fan applications requiring stable component supply across automotive production lifecycles.

Supply support for A3930KJP-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 IC solutions, founded in 1989 and headquartered in Worcester, Massachusetts.

The A3930KJP-T belongs to Allegro's automotive-qualified BLDC controller product line, engineered specifically for demanding under-hood motor control applications requiring extended temperature operation, robust fault diagnostics, and Hall-based commutation without MCU dependency.

FAQ

What is the key functional difference between A3930KJP-T and A3931KJP-T?

The A3930KJP-T asserts a logic fault when all three Hall inputs (H1/H2/H3) are low, whereas the A3931KJP-T enters pre-positioning mode in that state - forcing current into Phase A and sinking from Phases B/C to move the rotor to an unstable starting point. All other electrical specifications, pinout, and package are identical for A3930KJP-T and A3931KJP-T.

Does A3930KJP-T support 100% duty cycle high-side drive, and how is it implemented?

Yes, A3930KJP-T supports true 100% duty cycle high-side drive using an integrated top-off charge pump per high-side channel. This low-current (<100 μA) pump replenishes bootstrap capacitor leakage during sustained high-side conduction, ensuring gate voltage remains above threshold without requiring switching action - critical for holding torque in EPS and shutter actuation.

How does A3930KJP-T handle battery voltage drops during cold cranking?

A3930KJP-T maintains functional operation down to 5.5 V VBB with reduced gate drive, and guarantees full gate drive (>10 V) down to 7 V via its adaptive charge pump regulator. Below 7 V, the device switches from voltage-doubling to dropout mode to minimize power loss while sustaining gate drive integrity - a key feature validated for automotive cold-crank compliance.

Can A3930KJP-T be used without Hall-effect sensors?

No - A3930KJP-T requires Hall-effect sensor inputs (H1/H2/H3) for commutation sequencing and does not support sensorless back-EMF detection. Its internal logic is hardwired to decode 120°-spaced Hall states; for sensorless operation, a different controller such as the A4964 or external MCU-based solution is required. A3930KJP-T is strictly a Hall-sensored BLDC controller.

What is the purpose of the RDEAD pin on A3930KJP-T, and how is it configured?

The RDEAD pin on A3930KJP-T sets dead time between high-side and low-side FET switching to prevent shoot-through. A resistor from RDEAD to AGND configures tDEAD: 5 kΩ yields ~180 ns, 50 kΩ yields ~960 ns, and 400 kΩ yields ~3.3 μs. Connecting RDEAD to V5 defaults to 6 μs. This single-resistor adjustment replaces complex timing circuitry and ensures robust gate drive timing across temperature and voltage.