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Allegro MicroSystems A4940KLPTR-T
- Part No.:
- A4940KLPTR-T
- Manufacturer:
- Allegro MicroSystems
- Category:
- Motor Drivers, Controllers
- Package:
- 24-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
A4940KLPTR-T.pdf
- Description:
- IC MOTOR DRIVER 5.5V-50V 24TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,763
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Product details
Overview
A4940KLPTR-T from Allegro MicroSystems is an automotive-grade full-bridge MOSFET pre-driver IC designed to control external N-channel power MOSFETs in high-current inductive loads such as brush DC motors. It operates from 5.5 V to 50 V battery supply, delivers >10 V gate drive down to 7 V via integrated charge pump, and features user-adjustable dead time (0 ns to 6 µs), open-drain FAULT output, and thermal/undervoltage diagnostics.
For engineers reviewing the A4940KLPTR-T datasheet, A4940KLPTR-T pinout, A4940KLPTR-T application, or A4940KLPTR-T equivalent, this page provides verified technical context, validated pin functions, real-world automotive motor control use cases, and two confirmed alternative drivers with documented functional differences for design continuity planning.
Technical Context
The A4940KLPTR-T implements independent logic-level control of four external N-channel MOSFETs-two high-side (GHA/GHB) driven via bootstrap capacitors (CA/CB), and two low-side (GLA/GLB) referenced to AGND-with cross-conduction prevention enforced by resistor-programmable dead time on RDEAD. Its charge pump regulator maintains ≥10 V gate drive at VBB ≥ 7 V and supports functional operation down to 5.5 V with reduced drive voltage.
Diagnostics include latched bootstrap undervoltage (with auto-recovery on RESET), VREG and VDD undervoltage lockout, and overtemperature flag (170°C trip, 15°C hysteresis). The device enters low-current sleep mode when RESET is asserted, reducing VBB quiescent current to ≤10 µA while clearing fault latches.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VBB Supply Range | 5.5 V to 50 V - supports cold-crank (5.5 V) and load-dump (50 V) conditions in automotive systems without external regulation. |
| Gate Drive Voltage | ≥10 V typical at VBB ≥ 7 V - ensures robust N-MOSFET enhancement in high-side configuration using internal charge pump and bootstrap circuitry. |
| Dead Time Adjustment | 0 ns to 6 µs via RDEAD resistor (3 kΩ–240 kΩ) - prevents shoot-through during phase switching in motor H-bridge topologies. |
| Thermal Resistance | RθJA = 28 °C/W (4-layer PCB) - enables sustained operation up to 150°C junction temperature with appropriate board layout. |
| Diagnostic Outputs | Open-drain FAULT pin indicating VDD UV, VREG UV, bootstrap UV (latched), or overtemperature (non-latched) - simplifies system-level fault reporting with single-wire interface. |
| Logic Compatibility | 3.3 V or 5 V input thresholds (VIH = 0.7×VDD, VIL = 0.3×VDD) - interoperates directly with common microcontroller GPIO without level-shifting. |
| Package | 24-pin TSSOP with exposed thermal pad (LP suffix) - provides enhanced thermal dissipation for high-power motor drive applications. |
Pinout & Package
The A4940KLPTR-T is housed in a 24-pin TSSOP package with exposed thermal pad (suffix LP), RoHS-compliant and lead-free, with 100% matte tin leadframe plating.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VBAT / VBB | Main power supply input | Connects to unregulated battery rail (5.5–50 V); powers analog sections, charge pump, and high-side gate drivers. |
| VDD | Logic supply input | Accepts 3–5.5 V logic supply; powers digital control logic, inputs, and internal regulators. |
| GHA, GHB | High-side gate drive outputs | Source/sink current to gates of external high-side N-MOSFETs; require bootstrap capacitor (CA/CB) for floating supply. |
| GLA, GLB | Low-side gate drive outputs | Drive gates of external low-side N-MOSFETs; referenced to AGND; supply current from VREG-regulated rail. |
| SA, SB | Bridge output sense terminals | Direct connection to motor terminals; serve as return path for high-side bootstrap discharge and low-impedance switching node reference. |
| CA, CB | Bootstrap capacitor positive terminals | Supply boosted voltage to high-side drivers; charged to ~VREG when SA/SB are low; must be ≥220 nF ceramic. |
| AHI, ALO, BHI, BLO | Independent logic inputs | Direct 3.3/5 V-compatible control signals for each bridge leg; internal lockout prevents simultaneous high/low activation. |
| RDEAD | Dead time configuration | Resistor-to-ground sets dead time (0–6 µs); tied to VDD defaults to 6 µs; tied to GND disables internal dead time. |
| FAULT | Open-drain diagnostic output | Active-low flag indicating VDD UV, VREG UV, bootstrap UV (latched), or overtemperature (non-latched). |
| RESET | Active-low sleep/control input | Holding low disables all outputs, clears latched faults, and reduces VBB current to ≤10 µA; pulse clears bootstrap UV latch. |
| VREG | Regulated 13 V output | Supplies low-side gate drivers and bootstrap recharge current; requires ≥20×CBOOT storage capacitor (e.g., 10 µF for 500 nF CBOOT). |
| CP1, CP2 | Charge pump capacitor terminals | Connect external 470 nF ceramic capacitor; enables >10 V gate drive at VBB < 16 V via boost converter topology. |
Key Features
| Feature | Design Value |
|---|---|
| Charge pump + bootstrap architecture | Enables full 10+ V gate drive for N-MOSFETs across 5.5–50 V battery range - eliminates need for external high-voltage bias supplies in automotive H-bridges. |
| User-configurable dead time | Resistor-programmable delay (0–6 µs) between complementary MOSFET switching - prevents shoot-through without requiring precise timing from MCU firmware. |
| Latched bootstrap undervoltage detection | Automatically disables high-side outputs if CA/CB voltage drops below 59–69% of VREG and holds fault until RESET pulse - prevents MOSFET misfiring during PWM transitions. |
| Integrated diagnostics with single FAULT pin | Combines VDD UV, VREG UV, bootstrap UV, and overtemperature into one open-drain signal - reduces system wiring and simplifies host controller fault polling. |
| Low-power sleep mode | Reduces VBB quiescent current to ≤10 µA while maintaining connection to battery - enables always-on motor control modules without auxiliary switch. |
Applications
| Electric Power Steering (EPS) | Automotive HVAC Blower Motor |
|---|---|
|
Use Scenario: Bidirectional 12 V/24 V brushed DC motor control in safety-critical steering assist systems requiring fail-safe diagnostics and thermal monitoring. IC Role / Device Role / Timing Role: Pre-driver IC translating MCU PWM commands into high-current gate signals for external N-MOSFET H-bridge; manages dead time, bootstrap charging, and fault reporting. Use Value: Enables robust motor commutation under cold-crank (5.5 V) and load-dump (50 V) conditions while providing latched bootstrap UV detection to prevent loss of steering assist. |
Use Scenario: Variable-speed blower fan control in passenger cabin HVAC systems operating across wide ambient temperature range (−40°C to +125°C). IC Role / Device Role / Timing Role: Full-bridge gate driver interfacing 3.3 V microcontroller outputs to 40 A+ N-MOSFETs; provides independent phase control and dynamic braking capability. Use Value: Delivers >10 V gate drive at low battery voltages to ensure MOSFET saturation, minimizing conduction losses and enabling quiet, efficient airflow modulation. |
| Engine Cooling Fan Control | Seat/Mirror Actuator Drive |
|
Use Scenario: High-reliability radiator fan control in engine bays where junction temperatures exceed 130°C and EMI immunity is critical. IC Role / Device Role / Timing Role: Automotive-qualified pre-driver managing dual high-side/low-side gate signals with integrated overtemperature flag (170°C trip) and thermal shutdown hysteresis. Use Value: Maintains safe operation up to 150°C junction temperature with RθJA = 28 °C/W on 4-layer PCB, eliminating need for external thermal sensors or derating curves. |
Use Scenario: Compact, low-noise bidirectional actuation of seat/mirror adjustment motors in premium vehicle interiors. IC Role / Device Role / Timing Role: Low-quiescent-current (≤10 µA) gate driver supporting always-connected battery architecture; enables instant wake-up from sleep mode without MCU intervention. Use Value: Reduces parasitic drain on vehicle battery during long-term parking while retaining ability to respond immediately to door unlock or key-fob commands. |
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 |
|---|---|---|---|
| Toshiba TB9051FTG | Integrated N-channel half-bridge drivers (no external MOSFETs required); 40 V max VBB; no programmable dead time - fixed internal timing. | Targeted at space-constrained body electronics; lacks latched bootstrap UV detection and charge pump for sub-7 V operation. | Choose for simplified BOM and smaller footprint where battery voltage never drops below 7 V and diagnostic depth is secondary. |
| Infineon BTS7200-2EPA | Two-channel high-side switch (not full-bridge); 40 V max; integrated current sense; no gate drive flexibility - fixed 1.5 A output limit per channel. | Designed for solenoid/valve control, not motor commutation; cannot implement H-bridge or dynamic braking modes. | Choose only for unidirectional, low-current loads where independent high-side switching suffices and full-bridge functionality is unnecessary. |
Compared with A4940KLPTR-T, the TB9051FTG offers higher integration but sacrifices programmable dead time and sub-7 V gate drive capability, while the BTS7200-2EPA is functionally incompatible as a full-bridge solution - it serves only high-side switching applications with built-in current limiting and no low-side drive support.
Availability
A4940KLPTR-T is available at Aetrix Electronics and suitable for electric power steering, HVAC blower motor control, engine cooling fan systems, and seat/mirror actuator designs requiring stable component supply across extended automotive lifecycles.
Supply support for A4940KLPTR-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 and manufacturer of high-performance magnetic sensing and power IC solutions, specializing in automotive, industrial, and consumer motion-control applications.
The A4940KLPTR-T belongs to Allegro's automotive full-bridge pre-driver product line, engineered specifically for robust brushed DC motor control in harsh environments - emphasizing wide input voltage range, integrated diagnostics, and thermal resilience for safety-critical systems.
FAQ
Is A4940KLPTR-T still in production and available for new designs?
No, A4940KLPTR-T is a discontinued product as of July 1, 2024. Allegro MicroSystems states it should not be purchased for new design applications, and samples are no longer available. However, Aetrix Electronics maintains legacy inventory and supports existing production programs with traceable, lifecycle-managed supply for ongoing manufacturing needs.
What is the purpose of the RDEAD pin on A4940KLPTR-T, and how does it affect dead time?
The RDEAD pin on A4940KLPTR-T configures the internal dead time between high-side and low-side MOSFET switching to prevent shoot-through. Connecting a resistor (3–240 kΩ) between RDEAD and AGND sets dead time from 0 ns to 3.5 µs; tying RDEAD to VDD fixes it at 6 µs typical; connecting to GND disables internal dead time entirely. This allows precise tuning based on external MOSFET characteristics and layout parasitics.
How does A4940KLPTR-T handle bootstrap capacitor undervoltage, and what happens when it occurs?
When A4940KLPTR-T detects bootstrap capacitor voltage (CA/CB) falling below 59–69% of VREG, it initiates automatic recharge by activating the complementary low-side MOSFET. If recovery fails within ~200 µs, A4940KLPTR-T asserts the FAULT pin low and latches the condition - disabling high-side outputs until a RESET pulse clears the fault. This prevents unreliable high-side turn-on and ensures deterministic motor control behavior.
Can A4940KLPTR-T operate with a 3.3 V logic supply, and what are the input voltage thresholds?
Yes, A4940KLPTR-T supports 3.3 V logic supply on VDD. Its digital inputs (AHI, ALO, BHI, BLO, RESET) have hysteresis of 300–500 mV and threshold levels defined as VIH = 0.7 × VDD and VIL = 0.3 × VDD - so at 3.3 V VDD, VIH ≈ 2.31 V (min) and VIL ≈ 0.99 V (max). This ensures reliable interfacing with standard 3.3 V microcontrollers without level-shifting circuitry.
What thermal management considerations apply to A4940KLPTR-T in high-power motor drive applications?
A4940KLPTR-T has RθJA = 28 °C/W on a 4-layer JEDEC-standard PCB and RθJP = 2 °C/W to the exposed thermal pad. To maintain TJ ≤ 150°C in continuous operation, PCB layout must maximize copper area under the exposed pad and connect it to internal ground planes. Derating is required above 100°C ambient; thermal simulation using the provided RθJA/RθJP values is recommended before finalizing heatsinking strategy for A4940KLPTR-T.
A4940KLPTR-T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Allegro MicroSystems
- Series:
- -
- Package/Case:
- 24-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Motor Type - Stepper:
- -
- Motor Type - AC, DC:
- Brushed DC
- Function:
- Controller - Commutation, Direction Management
- Output Configuration:
- Pre-Driver - Half Bridge (2)
- Interface:
- On/Off
- Technology:
- Power MOSFET
- Step Resolution:
- -
- Applications:
- -
- Current - Output:
- -
- Voltage - Supply:
- 5.5V ~ 50V
- Voltage - Load:
- -
- Operating Temperature:
- -40°C ~ 150°C (TA)
- Grade:
- Automotive
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 24-TSSOP-EP
A4940KLPTR-T FAQ
1.How can I place an order for A4940KLPTR-T through Aetrix?
Please submit a Request for Quotation (RFQ) for A4940KLPTR-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 A4940KLPTR-T reliable?
The price and inventory of A4940KLPTR-T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for A4940KLPTR-T is usually 5 days.
3.What payment methods are accepted for A4940KLPTR-T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for A4940KLPTR-T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for A4940KLPTR-T?
A4940KLPTR-T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your A4940KLPTR-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 A4940KLPTR-T?
For technical support, including A4940KLPTR-T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your A4940KLPTR-T requirements.
6.How does Aetrix verify that A4940KLPTR-T is sourced from the original manufacturer or authorized distributors?
All A4940KLPTR-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 A4940KLPTR-T meets industry standards.
7.What is the process for return or replacement of A4940KLPTR-T?
All A4940KLPTR-T units undergo pre-shipment inspection (PSI). If there is an issue with A4940KLPTR-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 A4940KLPTR-T part is unused and in its original packaging.
Return procedure for A4940KLPTR-T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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