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Allegro MicroSystems A3950SLP-T
- Part No.:
- A3950SLP-T
- Manufacturer:
- Allegro MicroSystems
- Category:
- Motor Drivers, Controllers
- Package:
- 16-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
A3950SLP-T.pdf
- Description:
- IC MOTOR DRIVER 8V-36V 16TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,122
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Product details
Overview
A3950SLP-T from Allegro MicroSystems is a DMOS full-bridge motor driver IC designed for PWM-controlled DC motors, delivering ±2.8 A peak output current at up to 36 V supply voltage, with integrated synchronous rectification, thermal shutdown (175°C), and overcurrent protection (3 A threshold), used in compact industrial actuators and automotive seat/mirror control modules.
For engineers reviewing the A3950SLP-T datasheet, A3950SLP-T pinout, A3950SLP-T application, or A3950SLP-T equivalent, key selection criteria include its LP-package thermal pad layout, PHASE/ENABLE two-wire control interface, NFAULT diagnostic output behavior, and compatibility with 0.75 mm-height PCB space constraints in motor drive subsystems.
Technical Context
The A3950SLP-T implements dual N-channel DMOS H-bridge topology with independent source/sink drivers, each featuring RDS(on) ≤ 0.48 Ω (25°C) and body diode Vf ≤ 1.4 V. Its internal charge pump (CP1/CP2/VCP) generates gate drive above VBB for high-side switching, while VREG powers low-side drivers.
Control logic supports four operational modes via PHASE, ENABLE, MODE, and SLEEP inputs: forward/reverse drive, fast decay (synchronous rectification), slow decay (brake), and sleep (≤10 µA quiescent). Fault handling includes UVLO (6.5 V threshold), thermal warning (160°C), and 1.2 ms overcurrent recovery timing.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Peak Output Current | ±2.8 A - supports medium-power DC motors without external heatsinking under typical PCB thermal conditions |
| Supply Voltage Range | 8–36 V - compatible with 12 V and 24 V industrial and automotive battery systems |
| RDS(on) (Source/Sink) | 0.35–0.48 Ω / 0.30–0.43 Ω - enables <1.5 W conduction loss per channel at 2.8 A, reducing thermal load |
| Thermal Shutdown | 175°C with 15°C hysteresis - prevents permanent damage during sustained overload or poor airflow |
| Overcurrent Threshold | 3 A - triggers fault flag and disables outputs before MOSFET SOA violation occurs |
| Sleep Current | ≤10 µA - allows battery-powered devices to maintain multi-year standby life |
| NFAULT Output | Open-drain, active-low - signals thermal warning (160°C), UVLO, or overcurrent without external pull-up dependency |
Pinout & Package
Package: 16-pin TSSOP (LP) with exposed thermal pad (0.75 mm nominal height); pad must be soldered to PCB ground plane for thermal performance and electrical stability.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| NFAULT | Fault status output | Open-drain signal indicating thermal warning, UVLO, or overcurrent; requires external pull-up for system-level interrupt |
| MODE | Decay mode control | Logic-high selects slow-decay (brake) mode; logic-low enables fast-decay synchronous rectification |
| PHASE | Direction control input | Combined with ENABLE determines forward/reverse motor rotation; no internal pull-up/pull-down |
| GND | Power and signal ground | Pins 4 and 13 connect to PCB star ground point; exposed thermal pad must be tied to same ground net |
| SLEEP | Low-power enable | Logic-low disables regulator, charge pump, and drivers; wake-up requires ≥1 ms stabilization before PWM |
| ENABLE | Motor drive enable | Active-high input enabling PWM-controlled operation; disabled state forces outputs to high-impedance |
| OUTA / OUTB | H-bridge output terminals | Drive motor terminals directly; require external flyback path management via synchronous rectification |
| SENSE | Current sense return | Connects to low-value shunt resistor (e.g., 50 mΩ); ±500 mV max differential limits sensing resolution |
| VBB | Motor supply input | Accepts 8–36 V; requires 100 µF electrolytic + 0.1 µF ceramic decoupling close to pin |
| CP1 / CP2 / VCP | Charge pump network | CP1–CP2: 0.1 µF pumping cap; VCP–VBB: 0.1 µF reservoir cap - critical for high-side gate drive integrity |
| VREG | Regulator decoupling | Supplies sink-side drivers; requires 0.22 µF ceramic capacitor to GND for stable low-side operation |
| NC | No connection | Pin 16 is unconnected; must not be routed or soldered to avoid parasitic coupling |
Key Features
| Feature | Design Value |
|---|---|
| Synchronous rectification | Reduces power dissipation by replacing body-diode conduction with low-RDS(on) DMOS turn-on during decay cycles |
| Crossover-current protection | 500 ns delay between source/sink driver transitions prevents shoot-through and associated thermal stress |
| Integrated diagnostics | NFAULT pin reports real-time faults (thermal, UVLO, overcurrent) without requiring external monitoring circuitry |
| Thermal warning & shutdown | Two-stage thermal response: warning at 160°C (NFAULT active), shutdown at 175°C (outputs disabled) |
| Exposed thermal pad | Enables 34°C/W junction-to-ambient thermal resistance on 4-layer PCB - critical for maintaining <125°C junction temp at 2.8 A |
Applications
| Automotive Seat Adjustment | Industrial Linear Actuators |
|---|---|
|
Use Scenario: Bidirectional positioning of powered vehicle seats using 12–24 V DC motors with mechanical load feedback. IC Role / Device Role / Timing Role: Full-bridge driver executing PHASE/ENABLE PWM commands to control direction and speed; NFAULT monitors stall conditions. Use Value: Integrated overcurrent and thermal protection eliminates need for discrete current-sense amplifiers and external thermal sensors in space-constrained seat modules. |
Use Scenario: Precision extension/retraction of factory automation linear actuators under variable mechanical load. IC Role / Device Role / Timing Role: Motor driver implementing brake (slow-decay) mode via MODE pin to halt motion rapidly without mechanical braking hardware. Use Value: Synchronous rectification reduces heat generation during frequent start-stop cycles, extending actuator lifetime in enclosed enclosures. |
| Medical Infusion Pumps | Robotics Joint Control |
|
Use Scenario: Low-noise, reliable dosing control in portable infusion pumps powered by Li-ion batteries. IC Role / Device Role / Timing Role: Sleep-mode enabled driver minimizing standby current (<10 µA) between dose intervals; VBB range accommodates battery discharge curve. Use Value: Eliminates need for external enable FET and LDO, simplifying BOM and improving battery runtime per charge cycle. |
Use Scenario: Compact joint motor control in collaborative robots where board area and thermal mass are tightly constrained. IC Role / Device Role / Timing Role: H-bridge providing bidirectional torque with fast-decay mode for responsive position correction during dynamic motion. Use Value: LP-package height (≤1.2 mm) and exposed thermal pad allow integration into multi-layer motor controller PCBs without height interference. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar full-bridge motor driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TB9051FTG | Higher 4.5 A peak current, integrated current sense amplifier, SPI interface; larger 5×5 mm QFN package | Requires SPI host MCU and additional layout area; better suited for closed-loop torque control systems | Select when precise current measurement and digital configuration outweigh LP-package size constraints |
| VNH7040AS | Automotive-grade (AEC-Q100), higher 5.3 A continuous rating, built-in SPI diagnostics; 16-pin PowerSSO package | Designed for harsh environments; lacks synchronous rectification, increasing conduction losses at high duty cycles | Prefer for automotive body electronics where qualification and robustness supersede thermal efficiency |
Compared with TB9051FTG and VNH7040AS, the A3950SLP-T offers optimal balance of thermal performance (34°C/W), minimal footprint (TSSOP-LP), and analog control simplicity-making it ideal for cost-sensitive, space-constrained DC motor drives where SPI complexity or AEC-Q100 certification are unnecessary.
Availability
A3950SLP-T is available at Aetrix Electronics and suitable for automotive seat modules, industrial linear actuators, medical infusion pumps, and robotics joint controllers requiring stable component supply across multi-year production cycles.
Supply support for A3950SLP-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 and precision power ICs, with design centers in New Hampshire and global manufacturing partnerships.
The A3950 product line delivers highly integrated, thermally optimized motor drivers for brushed DC applications, targeting compact, reliable motion control in automotive, industrial, and medical equipment where board space and thermal headroom are limited.
FAQ
What is the maximum continuous output current supported by the A3950SLP-T?
The A3950SLP-T supports ±2.8 A peak output current, but continuous current depends on PCB thermal design. With the LP package on a 4-layer board, derating to ~1.8 A is typical at 85°C ambient to maintain junction temperature below 150°C. The datasheet specifies 2.8 A as a pulsed rating under defined test conditions, not a sustained DC value.
How does the A3950SLP-T implement synchronous rectification?
The A3950SLP-T automatically activates synchronous rectification during current decay phases by turning on the appropriate low-side DMOS switch instead of relying on the body diode. This occurs in both fast-decay and slow-decay modes, reducing conduction losses and heat generation. No external control is needed-the logic block manages timing internally based on PHASE, ENABLE, and MODE states.
Can the A3950SLP-T be used without connecting the exposed thermal pad?
No. The exposed thermal pad on the A3950SLP-T is electrically connected to GND and is mandatory for both thermal performance and electrical stability. Omitting pad connection increases RθJA to >60°C/W, causing premature thermal shutdown at currents far below 1 A. Allegro requires soldering the pad to a dedicated GND plane with thermal vias per JEDEC JESD51-5 guidelines.
What happens to the A3950SLP-T outputs during an overcurrent event?
When the A3950SLP-T detects overcurrent (≥3 A), it immediately disables both OUTA and OUTB, pulls NFAULT low, and starts a 1.2 ms fault timer. After expiration, it attempts automatic recovery-if the fault persists, the cycle repeats. During this time, PHASE/ENABLE inputs are ignored, and the device remains in latched fault state until the condition clears.
Is the A3950SLP-T pin-compatible with the A3950SEUTR-T?
No. Although both share identical functionality and pin functions, the A3950SLP-T (TSSOP-LP) and A3950SEUTR-T (QFN-EU) have different pinouts and physical footprints. The LP package assigns NFAULT to pin 1 and NC to pin 16, while the EU package places NFAULT at pin 15 and NC at pin 5. PCB layout and land patterns are not interchangeable.
A3950SLP-T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Allegro MicroSystems
- Series:
- -
- Package/Case:
- 16-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Packaging:
- Tube
- Product Status:
- Obsolete
- Motor Type - Stepper:
- -
- Motor Type - AC, DC:
- Brushed DC
- Function:
- Driver - Fully Integrated, Control and Power Stage
- Output Configuration:
- Half Bridge (2)
- Interface:
- Parallel
- Technology:
- DMOS
- Step Resolution:
- -
- Applications:
- General Purpose
- Current - Output:
- 2.8A
- Voltage - Supply:
- 8V ~ 36V
- Voltage - Load:
- 8V ~ 36V
- Operating Temperature:
- -20°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-eTSSOP-EP
A3950SLP-T FAQ
1.How can I place an order for A3950SLP-T through Aetrix?
Please submit a Request for Quotation (RFQ) for A3950SLP-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 A3950SLP-T reliable?
The price and inventory of A3950SLP-T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for A3950SLP-T is usually 5 days.
3.What payment methods are accepted for A3950SLP-T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for A3950SLP-T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for A3950SLP-T?
A3950SLP-T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your A3950SLP-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 A3950SLP-T?
For technical support, including A3950SLP-T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your A3950SLP-T requirements.
6.How does Aetrix verify that A3950SLP-T is sourced from the original manufacturer or authorized distributors?
All A3950SLP-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 A3950SLP-T meets industry standards.
7.What is the process for return or replacement of A3950SLP-T?
All A3950SLP-T units undergo pre-shipment inspection (PSI). If there is an issue with A3950SLP-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 A3950SLP-T part is unused and in its original packaging.
Return procedure for A3950SLP-T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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