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Allegro MicroSystems AMT49700KETJTR
- Part No.:
- AMT49700KETJTR
- Manufacturer:
- Allegro MicroSystems
- Category:
- Motor Drivers, Controllers
- Package:
- 32-VFQFN Exposed Pad
- Datasheet:
-
AMT49700KETJTR.pdf
- Description:
- AUTOMOTIVE STEPPER MOTOR DRIVER
- Quantity:
- Payment:
- Shipping:
Inventory:696
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Product details
Overview
AMT49700KETJTR from Allegro MicroSystems is an automotive-grade bipolar stepper motor driver IC with integrated phase current control, SPI-configurable motion engine, and adaptive mixed-decay PWM. It delivers up to ±1.6 A phase current at 28 V, supports full/half/quarter/eighth/sixteenth microstepping, and operates from –40°C to +150°C ambient. Used in headlamp positioning, HVAC flap control, and engine management systems.
For engineers reviewing the AMT49700KETJTR datasheet, AMT49700KETJTR pinout, AMT49700KETJTR application, or AMT49700KETJTR equivalent, this page provides verified technical context, real-world diagnostic capabilities, programmable acceleration/deceleration profiles, thermal warning thresholds, and SPI register-level motion control-critical for automotive ECU integration and functional safety–aware motor actuation design.
Technical Context
The AMT49700KETJTR integrates two DMOS full-bridge drivers with synchronous rectification and adaptive mixed-decay current regulation, enabling precise 16-microstep positioning while minimizing audible noise and torque ripple. Its fixed-frequency PWM (16.4–27.8 kHz, ditherable) operates with programmable blank time (1–3.5 µs) and on-time (disable to 56 µs), directly tied to current trip accuracy (±10% for high-current modes).
Control is fully SPI-based (16-bit, 50 ns min clock high/low), supporting both single-step commands (SC[5:0] two's complement) and full motion profiles (ACC/DEC/SSR/RSR/NSM/NSL registers). Diagnostics-including hot warning (125–145°C), overtemperature shutdown (170–180°C), open-load detection (8–39 mA threshold), and short-circuit fault blanking (1.9–2.1 µs)-are reported via dedicated DIAG pin and serial status registers.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage Range | 3.7 V to 42 V - supports direct connection to automotive 12 V and 24 V power nets with overvoltage lockout at 32–36 V and undervoltage lockout at 4.7–5.1 V. |
| Peak Phase Current | ±1.6 A - enables driving NEMA17-class stepper motors in high-torque automotive applications without external current sensing. |
| RDS(ON) (HS/Low-Side) | 500 mΩ typical - reduces conduction loss and thermal stress during continuous operation at 150°C ambient. |
| Microstep Resolution | Full, half, quarter, eighth, sixteenth - selectable via MS[2:0] pins or SPI register, with step angle resolution down to 0.1125° for a 1.8° motor. |
| PWM Frequency | 16.4–27.8 kHz - configurable dither spreads spectral energy to meet CISPR 25 Class 5 EMC requirements. |
| Thermal Protection | Hot warning at 125–145°C; shutdown at 170–180°C - enables fail-safe behavior in enclosed under-hood environments. |
| Diagnostic Output | Single-pin DIAG with fault flag or analog temperature voltage (1440 mV @ 135°C, –3.92 mV/°C slope) - simplifies system-level fault monitoring without ADC overhead. |
Pinout & Package
AMT49700KETJTR is housed in a 32-terminal 5 mm × 5 mm QFN package with exposed thermal pad (suffix ET), optimized for high-power dissipation in automotive under-hood applications. Thermal resistance RθJA = 30°C/W on high-K multilayer PCB per JEDEC JESD51-7.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| STEP | Step pulse input | Rising-edge-triggered logic input with 1 µs input filter; advances motor one microstep when DIR is asserted and STEP mode is active. |
| DIR | Direction control | Logic-level input defining forward/backward direction for STEP/DIR mode; ignored during SPI motion profile execution. |
| OAP / OAM | Phase A bridge outputs | DMOS full-bridge terminals for bipolar stepper winding A; OAP = high-side source, OAM = low-side sink. |
| OBP / OBM | Phase B bridge outputs | DMOS full-bridge terminals for bipolar stepper winding B; polarity defines motor rotation direction in conjunction with phase sequencing. |
| SCK / SDI / SDO / STRn | SPI interface | 16-bit, MSB-first serial interface with chip select (STRn), clock (SCK), data in (SDI), and data out (SDO); SDO reflects FF bit of Status register on STRn falling edge. |
| DIAG | Dual-function diagnostic output | Configurable via SPI: default fault flag (open-drain), or analog voltage proportional to die temperature (1440 mV at 135°C). |
| RESETn | Reset and sleep control | Active-low input: <1.5–8 µs pulse clears faults; >40 µs low forces sleep mode (20–100 µA quiescent current). |
| VBB (Pins 14 & 27) | Main motor supply | Accepts 3.7–42 V; powers bridges, charge pump, and internal regulators; requires local ceramic + electrolytic decoupling. |
| CP1 / CP2 / VCP | Charge pump network | Generates gate drive voltage above VBB for high-side MOSFETs; CP1–CP2 = 100 nF, VCP–VBB = 100 nF (16 V). |
| GND / GNDPA / GNDPB | Ground terminals | Separate power grounds for logic (GND), phase A (GNDPA), and phase B (GNDPB); must be connected together at single-point star ground per layout guidelines. |
Key Features
| Feature | Design Value |
|---|---|
| Programmable motion profile | Single SPI command configures independent acceleration (0–63 full steps/s²), deceleration, start/run speed, and step count-enabling smooth, jerk-free positioning without host MCU intervention. |
| Adaptive mixed-decay current control | Automatically adjusts fast/slow decay ratio per PWM cycle to minimize current ripple and audible motor noise across load, temperature, and supply variations. |
| Synchronous rectification | Reduces power dissipation by replacing freewheeling diode conduction with active low-RDS(ON) MOSFET conduction during off-time. |
| Output slew rate control | Two programmable levels (30 V/µs or 100 V/µs) suppress EMI generation during switching transitions in sensitive automotive domains. |
| Comprehensive diagnostics | Real-time detection of open-load (8–39 mA), short-to-VBB/ground, overtemperature (warning + shutdown), and overvoltage/undervoltage-with fault status readable via SPI or latched on DIAG pin. |
Applications
| Headlamp Positioning | HVAC Flap Control |
|---|---|
Use Scenario: Precise angular adjustment of LED headlamp modules for adaptive driving beam (ADB) and automatic leveling functions. IC Role / Device Role / Timing Role: Stepper motor driver executing closed-loop position commands via SPI from body control module (BCM), with microsecond-level step timing and thermal derating awareness. Use Value: Enables ±0.1° positioning accuracy using 16-microstep mode and adaptive decay, meeting UNECE R112 photometric stability requirements under 125°C under-hood conditions. | Use Scenario: Actuation of HVAC blend, mode, and recirculation flaps in passenger cabin climate control systems. IC Role / Device Role / Timing Role: Low-noise, high-reliability motor driver operating from vehicle battery (9–16 V), with built-in open-load detection to confirm actuator engagement before movement. Use Value: Eliminates need for external current sense or position feedback; 20–100 µA sleep current extends battery life during vehicle off-state; DIAG pin reports open-load or thermal fault to HVAC controller. |
| Engine Throttle Control | Exhaust Gas Recirculation (EGR) |
Use Scenario: Drive-by-wire throttle valve positioning in gasoline and hybrid powertrains where cable-free actuation is required. IC Role / Device Role / Timing Role: Safety-aware motor driver with hot warning (125–145°C) and overtemperature shutdown (170–180°C), interfacing to ASIL-B compliant ECU via SPI with CRC-protected register access. Use Value: Supports functional safety goals via diagnostic coverage of bridge faults, supply monitors, and thermal events-reducing need for redundant sensors in throttle actuation subsystems. | Use Scenario: Precise control of EGR valve opening to regulate NOx emissions in diesel and gasoline direct injection engines. IC Role / Device Role / Timing Role: High-temp stepper driver operating in exhaust proximity (up to 150°C ambient), using programmable acceleration/deceleration to avoid mechanical shock on valve linkage. Use Value: Maintains ±1.6 A drive capability at elevated temperatures; adaptive decay minimizes torque ripple that could cause valve chatter; short-circuit protection prevents latch-up during condensation-induced faults. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar stepper motor driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TMC2209-LA | Integrated UART interface, stealthChop2 silent stepping, lower max current (1.4 A), no automotive temp grade (–40°C to +125°C only) | Targeted at consumer/industrial 3D printers and CNC; lacks hot warning, overtemperature shutdown, and diagnostic registers needed for ISO 26262 compliance | Select TMC2209-LA only for non-automotive, cost-sensitive applications where silent operation outweighs thermal robustness and diagnostics. |
| DRV8886AT | Higher RDS(ON) (800 mΩ typ), no motion engine, no adaptive decay, SPI-only (no STEP/DIR fallback), 1.5 A peak current | Designed for industrial automation with simpler control; lacks automotive qualification, open-load detection, and programmable dither for EMC | Choose DRV8886AT when motion control is handled entirely by host MCU and automotive-grade thermal protection is not required. |
Compared with TMC2209-LA and DRV8886AT, AMT49700KETJTR uniquely combines ASIL-ready diagnostics (hot warning, open-load, short-circuit), 150°C ambient operation, and embedded motion profiling-making it the only option qualified for safety-critical automotive actuation where host MCU resources are constrained and environmental ruggedness is mandatory.
Availability
AMT49700KETJTR is available at Aetrix Electronics and suitable for automotive headlamp positioning, HVAC flap control, and engine management systems requiring stable component supply, long-term lifecycle support, and AEC-Q100 Grade 0 qualification.
Supply support for AMT49700KETJTR 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 global leader in precision sensing and power ICs, headquartered in Manchester, NH, with deep expertise in magnetic sensing, motor control, and automotive semiconductor solutions.
The AMT49700KETJTR belongs to Allegro's Automotive Stepper Driver product line, engineered specifically for high-temperature, safety-critical motor actuation in modern vehicles-including adaptive lighting, climate control, and powertrain systems-where reliability, integrated diagnostics, and minimal host processing overhead are essential.
FAQ
What is the maximum ambient temperature rating for AMT49700KETJTR?
The AMT49700KETJTR is rated for continuous operation from –40°C to +150°C ambient temperature, with transient junction temperature tolerance up to 175°C for ≤10 seconds. This makes it suitable for under-hood automotive applications such as headlamp leveling and EGR valve control where thermal margins are critical. The device implements hot warning at 125–145°C and overtemperature shutdown at 170–180°C to protect itself and the motor system.
Does AMT49700KETJTR support both STEP/DIR and SPI control simultaneously?
No-AMT49700KETJTR operates in mutually exclusive control modes. When STEP and DIR pins are used for motion control, the SPI interface is limited to configuration and diagnostics only. During SPI motion profile execution (via ACC/DEC/RSR registers), the STEP and DIR inputs are ignored. The AMT49700KETJTR automatically disables STEP/DIR functionality upon receipt of a valid motion profile command, ensuring deterministic behavior in safety-critical automotive systems.
How does the adaptive mixed-decay feature improve motor performance in AMT49700KETJTR?
The adaptive mixed-decay feature in AMT49700KETJTR dynamically adjusts the ratio of fast and slow current decay within each PWM cycle based on real-time phase current and voltage conditions. This reduces current ripple and torque variation across motor speeds and loads, resulting in lower audible noise, smoother motion, and improved step accuracy-especially critical in headlamp positioning and HVAC applications where mechanical vibration must be minimized.
Can AMT49700KETJTR detect open-load conditions on stepper windings?
Yes-AMT49700KETJTR includes configurable open-load detection with two sensitivity thresholds: 8–25 mA (default) or 21–39 mA. It monitors current flow during active decay phases and reports open-load faults via the DIAG pin and SPI Status Register (bit OLF). This allows early detection of disconnected or broken motor windings before attempting motion, preventing erroneous positioning and enabling system-level fault recovery in automotive ECUs.
What package type and thermal characteristics apply to AMT49700KETJTR?
AMT49700KETJTR uses a 32-pin 5 mm × 5 mm QFN package with exposed thermal pad (suffix ET). Its thermal resistance is RθJA = 30°C/W on a high-K multilayer PCB per JEDEC JESD51-7. The exposed pad must be soldered to a large copper pour for optimal heat transfer. This package enables reliable 1.6 A operation at 150°C ambient when properly mounted, meeting AEC-Q100 Grade 0 requirements for under-hood automotive use.
AMT49700KETJTR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Allegro MicroSystems
- Series:
- -
- Package/Case:
- 32-VFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Motor Type - Stepper:
- Bipolar
- Motor Type - AC, DC:
- Brushed DC
- Function:
- Controller - Commutation, Direction Management
- Output Configuration:
- Half Bridge (4)
- Interface:
- Serial
- Technology:
- Power MOSFET
- Step Resolution:
- 1, 1/2, 1/4, 1/8, 1/16
- Applications:
- -
- Current - Output:
- 1.6A
- Voltage - Supply:
- 0V ~ 42V
- Voltage - Load:
- -
- Operating Temperature:
- -40°C ~ 150°C (TA)
- Grade:
- Automotive
- Qualification:
- -
- Mounting Type:
- Surface Mount, Wettable Flank
- Supplier Device Package:
- 32-QFN (5x5)
AMT49700KETJTR FAQ
1.How can I place an order for AMT49700KETJTR through Aetrix?
Please submit a Request for Quotation (RFQ) for AMT49700KETJTR 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 AMT49700KETJTR reliable?
The price and inventory of AMT49700KETJTR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AMT49700KETJTR is usually 5 days.
3.What payment methods are accepted for AMT49700KETJTR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AMT49700KETJTR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AMT49700KETJTR?
AMT49700KETJTR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AMT49700KETJTR 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 AMT49700KETJTR?
For technical support, including AMT49700KETJTR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AMT49700KETJTR requirements.
6.How does Aetrix verify that AMT49700KETJTR is sourced from the original manufacturer or authorized distributors?
All AMT49700KETJTR 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 AMT49700KETJTR meets industry standards.
7.What is the process for return or replacement of AMT49700KETJTR?
All AMT49700KETJTR units undergo pre-shipment inspection (PSI). If there is an issue with AMT49700KETJTR, 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 AMT49700KETJTR part is unused and in its original packaging.
Return procedure for AMT49700KETJTR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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