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

Allegro MicroSystems A3946KLB

Name: A3946KLB
Brand: Allegro MicroSystems
SKU: A3946KLB
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: A3946KLB

Manufacturer:: Allegro MicroSystems

Category:: Motor Drivers, Controllers

Package:: 16-PowerSOIC (0.295", 7.50mm Width)

Datasheet:: A3946KLB.pdf

Description:: IC MOTOR DRIVER 7V-60V 16SOIC

Quantity:: RFQ Add To RFQ list

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Product details

Overview

A3946KLB from Allegro MicroSystems is a half-bridge power MOSFET controller designed to drive high-current N-channel MOSFETs in unidirectional DC motor and three-phase BLDC motor applications. It features dual gate drivers (GH and GL), integrated top-off charge pump enabling 100% duty cycle operation, VREG output at 13 V nominal, and operates across –40°C to +135°C ambient temperature.

For engineers reviewing the A3946KLB datasheet, A3946KLB pinout, A3946KLB application, or A3946KLB equivalent, key selection criteria include bootstrap-enabled high-side drive capability, programmable dead time via DT pin, thermal shutdown at 170°C, undervoltage protection on VREG/BOOT/VREF, and compatibility with 7–60 V load supply voltage.

Technical Context

The A3946KLB implements a dual-output gate driver architecture with independent high-side (GH) and low-side (GL) outputs, each capable of sourcing/sinking >1 A peak current. Its internal top-off charge pump sustains high-side gate voltage during continuous conduction, eliminating shoot-through risk through configurable dead time (350 ns to 6 µs) set by external R_DEAD.

Control logic supports both single-pin PWM (IN1=IN2) and independent input modes (DT tied to VREF). Fault diagnostics include latched overtemperature (170°C), VREG undervoltage (8.3 V trip), BOOT undervoltage (7.8 V trip), and non-latched VREF undervoltage - all reported via open-drain ~FAULT pin.

Key Specifications

Parameter	Value and Actual Design Meaning
VBB Supply Range	7 V to 60 V - enables direct integration into 12 V, 24 V, and 48 V industrial/motor control systems without external regulators.
VREG Output	13 V ±0.5 V at 15 mA - powers low-side gate drive and bootstraps high-side circuitry; regulated internally for stable gate bias.
Gate Drive Rise/Fall Time	60 ns / 40 ns (typ.) with 3300 pF load - ensures fast switching transitions while maintaining EMI control via external RGATE.
Dead Time Range	350 ns to 6 µs - adjustable via R_DEAD (5 kΩ–100 kΩ) to prevent cross-conduction in half-bridge configurations.
Thermal Shutdown	170°C junction temperature with 15°C hysteresis - protects device under overload or poor heatsinking without disabling logic inputs.
Logic Input Thresholds	IN1/IN2 high ≥2.0 V, low ≤0.8 V; RESET high ≥2.2 V - compatible with standard 3.3 V and 5 V microcontrollers.
Charge Pump Frequency	62.5 kHz - provides stable VREG regulation across input voltage range with efficiency dropping from 80% (VBB = 7 V) to 20% (VBB = 50 V).

Pinout & Package

Package: 16-lead TSSOP with exposed thermal pad (LP suffix), RoHS-compliant, 100% matte tin plated leadframe.

Pin/Terminal	Circuit Role	Design Meaning
VREG (1)	Regulated gate drive supply output	13 V source for GL and bootstrap capacitor charging; requires 10 µF decoupling capacitor.
CP2 (2), CP1 (3)	Charge pump capacitor terminals	Form external flying capacitor network for VREG generation; CP2 positive, CP1 negative.
PGND (4)	Power ground reference	Separate from LGND; must be connected externally to minimize high-current return path noise.
GL (5)	Low-side gate driver output	Drives N-MOSFET source terminal; slew rate controlled by external series resistor.
S (6)	Load connection / bootstrap return	Common node between motor/load and bootstrap capacitor negative; referenced by GH driver.
GH (7)	High-side gate driver output	Drives N-MOSFET drain-side gate; floating output powered by BOOT voltage and top-off charge pump.
BOOT (8)	High-side bootstrap supply	Positive rail for GH driver; charged via internal diode during GL ON phase; requires 0.22 µF X7R ceramic capacitor.
~FAULT (9)	Open-drain fault indicator	Asserts low for latched faults (overtemp, VREG UVLO); non-latched faults (BOOT UVLO, VREF UVLO) also pull low but auto-clear.
IN1, IN2 (10–11)	Digital control inputs	Configure half-bridge state (H/L, L/H, L/L, H/H); support PWM or direction/enable schemes.
RESET (12)	Active-low sleep enable	Pulls all outputs high-Z and reduces quiescent current to 10 µA when held low >10 µs.
LGND (13)	Logic ground reference	Independent of PGND; must be connected externally to ensure clean digital interface operation.
DT (14)	Analog dead-time programming	Resistor-to-ground sets delay between GH/GL turn-off and subsequent turn-on; tie to VREF to disable dead time.
VREF (15)	Internal 5 V reference output	Decoupled with 0.1 µF capacitor; supplies logic and can source up to 4 mA for external circuitry.
VBB (16)	Main load supply input	Accepts 7–60 V; powers charge pump, logic, and gate drivers; quiescent current 3–6 mA (active), 10 µA (sleep).
PAD	Exposed thermal pad	Not electrically connected; must be soldered to PCB ground plane with thermal vias for junction temperature control.

Key Features

Feature	Design Value
Integrated top-off charge pump	Enables true 100% duty cycle high-side N-MOSFET operation without external boost circuitry.
Programmable dead time	Adjustable 350 ns–6 µs via single external resistor (R_DEAD) to prevent shoot-through in half-bridge topologies.
Dual independent gate drivers	GH and GL outputs each deliver >1 A peak current with matched rise/fall times for balanced switching performance.
Comprehensive fault protection	Latched overtemperature (170°C), VREG/BOOT undervoltage, and non-latched VREF undervoltage with open-drain ~FAULT reporting.
Wide operating temperature range	–40°C to +135°C ambient rating supports under-hood automotive, industrial motor drives, and harsh-environment applications.
Low-power sleep mode	RESET = 0 reduces VBB current to 10 µA while maintaining pin states in high-impedance - ideal for battery-powered systems.

Applications

Automotive HVAC Blower Control	Industrial Conveyor Motor Drive
Use Scenario: Precise speed and direction control of 24 V DC blower motors in vehicle climate systems. IC Role / Device Role / Timing Role: Half-bridge gate driver controlling high-side and low-side N-MOSFETs; manages PWM timing, dead time, and thermal safety. Use Value: Enables compact, efficient 24 V motor control with built-in overtemperature shutdown and fault reporting to ECU via ~FAULT pin.	Use Scenario: Bidirectional control of 48 V DC conveyor belt motors in factory automation systems. IC Role / Device Role / Timing Role: Gate driver for external N-MOSFET half-bridge; provides VREG-regulated gate bias and programmable dead time for robust commutation. Use Value: Eliminates need for discrete charge pump or level-shifters; supports 48 V bus directly with 60 V absolute max rating on VBB and GH pins.
Medical Infusion Pump Actuation	Robotics Joint Actuator Module
Use Scenario: Low-noise, precise unidirectional DC motor control in portable infusion pumps requiring fail-safe operation. IC Role / Device Role / Timing Role: High-reliability gate driver with latched thermal fault and VREG UVLO detection; interfaces with microcontroller via IN1/IN2 and RESET. Use Value: Ensures motor stops safely during overtemperature or supply drop; ~FAULT signal triggers system-level alarm and shutdown.	Use Scenario: Compact, high-efficiency motor driver stage in articulated robotic joints using 12–24 V brushed DC or BLDC motors. IC Role / Device Role / Timing Role: Dual gate driver supporting both dependent (PWM+DIR) and independent control modes; DT pin allows fine-tuned dead time for dynamic loads. Use Value: Reduces BOM count by integrating charge pump, VREG, VREF, and protection - critical for space-constrained robotic modules.

Automotive HVAC Blower Control

Industrial Conveyor Motor Drive

Use Scenario: Precise speed and direction control of 24 V DC blower motors in vehicle climate systems.

IC Role / Device Role / Timing Role: Half-bridge gate driver controlling high-side and low-side N-MOSFETs; manages PWM timing, dead time, and thermal safety.

Use Value: Enables compact, efficient 24 V motor control with built-in overtemperature shutdown and fault reporting to ECU via ~FAULT pin.

Use Scenario: Bidirectional control of 48 V DC conveyor belt motors in factory automation systems.

IC Role / Device Role / Timing Role: Gate driver for external N-MOSFET half-bridge; provides VREG-regulated gate bias and programmable dead time for robust commutation.

Use Value: Eliminates need for discrete charge pump or level-shifters; supports 48 V bus directly with 60 V absolute max rating on VBB and GH pins.

Medical Infusion Pump Actuation

Robotics Joint Actuator Module

Use Scenario: Low-noise, precise unidirectional DC motor control in portable infusion pumps requiring fail-safe operation.

IC Role / Device Role / Timing Role: High-reliability gate driver with latched thermal fault and VREG UVLO detection; interfaces with microcontroller via IN1/IN2 and RESET.

Use Value: Ensures motor stops safely during overtemperature or supply drop; ~FAULT signal triggers system-level alarm and shutdown.

Use Scenario: Compact, high-efficiency motor driver stage in articulated robotic joints using 12–24 V brushed DC or BLDC motors.

IC Role / Device Role / Timing Role: Dual gate driver supporting both dependent (PWM+DIR) and independent control modes; DT pin allows fine-tuned dead time for dynamic loads.

Use Value: Reduces BOM count by integrating charge pump, VREG, VREF, and protection - critical for space-constrained robotic modules.

Equivalent & Alternatives

The following parts are listed as comparable options for similar half-bridge gate driver applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
MP6542GQ-Z (Monolithic Power)	Single-chip half-bridge with integrated MOSFETs (40 V, 3 A); no external gate resistors needed; lacks top-off charge pump for 100% duty cycle.	Best for lower-power (<100 W), space-constrained designs where integrated FETs suffice; unsuitable for high-voltage or high-current external FET use.	Select MP6542GQ-Z only if load current ≤3 A and VBB ≤40 V; A3946KLB remains preferred for >40 V, >10 A, or 100% duty cycle requirements.
TBD62783AFG,EL (Toshiba)	High-side/low-side driver with built-in level shifters; supports 36 V max VBB; no integrated charge pump - requires external bootstrap diode/capacitor network.	Designed for 24 V industrial PLC I/O modules; lacks VREG regulator and top-off functionality, increasing external component count.	Choose TBD62783AFG,EL for cost-sensitive 24 V systems with fixed dead time; A3946KLB offers superior integration, wider voltage range, and full-duty-cycle capability.

Compared with MP6542GQ-Z and TBD62783AFG,EL, the A3946KLB uniquely combines 60 V VBB rating, integrated top-off charge pump for 100% duty cycle, programmable dead time, and comprehensive fault reporting - making it optimal for high-reliability, high-voltage motor control where external MOSFETs and thermal resilience are required.

Availability

A3946KLB is available at Aetrix Electronics and suitable for automotive HVAC systems, industrial conveyor drives, medical infusion pumps, and robotics joint actuators requiring stable component supply, AEC-Q100-aligned reliability, and long-term production continuity.

Supply support for A3946KLB 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, motor drivers, and power ICs, serving automotive, industrial, and consumer markets since 1989.

The A3946 product line delivers robust, integrated half-bridge gate drivers for high-power DC and BLDC motor control - engineered specifically for demanding applications requiring wide input voltage range, thermal resilience, and fault-aware operation.

FAQ

What is the maximum VBB voltage rating for the A3946KLB?

The A3946KLB has an absolute maximum VBB rating of 60 V, with recommended operating range from 7 V to 60 V. This allows direct use in 12 V, 24 V, and 48 V motor control systems. Exceeding 60 V risks permanent damage to internal circuitry, especially the GH and BOOT pins, which share the same 75 V absolute max rating. Always observe derating guidelines per PCB thermal design.

Does the A3946KLB support 100% duty cycle operation for the high-side MOSFET?

Yes, the A3946KLB supports true 100% duty cycle high-side operation via its internal top-off charge pump. Unlike basic bootstrap drivers that require periodic low-side conduction to recharge the BOOT capacitor, the A3946KLB's trickle-charge pump maintains GH gate voltage continuously - critical for applications like brake-hold or static torque control in DC motor systems.

How does the ~FAULT pin behave during different fault conditions?

The ~FAULT pin is an open-drain output that pulls low for all active faults. Latched faults (overtemperature, VREG undervoltage) remain asserted until RESET is pulsed low; non-latched faults (BOOT undervoltage, VREF undervoltage) clear automatically when the condition resolves. The A3946KLB does not disable outputs during non-latched faults - only latched faults inhibit gate drive activation until cleared.

What is the purpose of separate PGND and LGND pins on the A3946KLB?

PGND (Pin 4) and LGND (Pin 13) are internally isolated grounds: PGND carries high-current return paths for gate drivers and charge pump, while LGND serves low-noise logic and reference circuits. Both must be connected externally to system ground - ideally via separate low-impedance traces - to prevent coupling of switching noise into control logic and ensure accurate VREF/VREG regulation and fault detection in the A3946KLB.

Can the A3946KLB drive both N-channel and P-channel MOSFETs?

The A3946KLB is designed exclusively for driving N-channel MOSFETs in half-bridge configuration: GH drives high-side N-MOSFETs using bootstrap/top-off techniques, and GL drives low-side N-MOSFETs directly. It does not support P-channel high-side drivers, as its architecture relies on N-MOSFET advantages (lower R_DS(on), higher efficiency) and integrates no level-shifting circuitry for P-FET gate control.

A3946KLB Specifications

Product attributes: Attribute value

Manufacturer:: Allegro MicroSystems

Series:: -

Package/Case:: 16-PowerSOIC (0.295", 7.50mm Width)

Packaging:: Tube

Product Status:: Obsolete

Motor Type - Stepper:: -

Motor Type - AC, DC:: Brushless DC (BLDC)

Function:: Controller - Commutation, Direction Management

Output Configuration:: Pre-Driver - Half Bridge

Interface:: Parallel

Technology:: Power MOSFET

Step Resolution:: -

Applications:: General Purpose

Current - Output:: -

Voltage - Supply:: 7V ~ 60V

Voltage - Load:: -

Operating Temperature:: -40°C ~ 135°C (TA)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 16-SOIC

A3946KLB FAQ

1.How can I place an order for A3946KLB through Aetrix?

Please submit a Request for Quotation (RFQ) for A3946KLB 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 A3946KLB reliable?

The price and inventory of A3946KLB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for A3946KLB is usually 5 days.

3.What payment methods are accepted for A3946KLB?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for A3946KLB transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for A3946KLB?

A3946KLB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your A3946KLB 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 A3946KLB?

For technical support, including A3946KLB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your A3946KLB requirements.

6.How does Aetrix verify that A3946KLB is sourced from the original manufacturer or authorized distributors?

All A3946KLB 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 A3946KLB meets industry standards.

7.What is the process for return or replacement of A3946KLB?

All A3946KLB units undergo pre-shipment inspection (PSI). If there is an issue with A3946KLB, 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 A3946KLB part is unused and in its original packaging.

Return procedure for A3946KLB:

1.Submit a request within 90 days.

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

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