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Texas Instruments UC3770AQTR
- Part No.:
- UC3770AQTR
- Manufacturer:
- Texas Instruments
- Category:
- Full Half-Bridge (H Bridge) Drivers
- Package:
- 28-LCC (J-Lead)
- Datasheet:
-
UC3770AQTR.pdf
- Description:
- IC HALF BRIDGE DRIVER 2A 28PLCC
- Quantity:
- Payment:
- Shipping:
Inventory:2,730
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Product details
Overview
UC3770AQTR from Texas Instruments is a high-performance full-bridge stepper motor driver IC designed for bipolar stepper motor control in microprocessor-based motion systems. It delivers up to 2A output current, supports 10–45V motor supply voltage, features integrated current sense and thermal shutdown, and enables full-step, half-step, and micro-step operation in industrial automation and CNC positioning systems.
For engineers reviewing the UC3770AQTR datasheet, UC3770AQTR pinout, UC3770AQTR application, or UC3770AQTR equivalent, key selection considerations include its LS-TTL-compatible logic inputs, 400–430mV current-sense comparator threshold (matching UC3717 for drop-in replacement), thermal shutdown at +170°C, and requirement for external high-side clamp diodes.
Technical Context
The UC3770AQTR implements a monolithic H-bridge power stage with separate source and sink drivers, each rated for ±2A continuous output. Its current regulation uses an internal comparator with programmable off-time via RT/CT network and three selectable current thresholds (via I0/I1 logic inputs) - 400mV, 255mV, and 80mV - enabling discrete current levels for stepping modes.
Unlike the UC3717, the UC3770AQTR requires external high-side clamp diodes due to absence of integrated flyback paths. Its logic interface operates at 4.75–5.3V VCC with TTL-compatible thresholds (0.8V low / 2.0V high), and thermal protection triggers at +170°C with soft intervention to prevent abrupt shutdown during overload.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current | ±2A continuous - drives NEMA 17–23 bipolar stepper motors directly without external amplification |
| Motor Supply Voltage | 10–45V - supports wide-range DC bus operation in industrial motor controllers |
| Current Sense Threshold | 400/255/80mV - selects 100%/71%/50% current levels for full/half/micro-stepping |
| Sink Saturation Voltage | 0.8V @ 1.0A - reduces conduction loss and heat generation in low-side switching path |
| Source Saturation Voltage | 1.3V @ 1.0A - defines upper-bound voltage drop across high-side driver during on-state |
| Thermal Shutdown | +170°C - protects die under sustained overload or poor heatsinking conditions |
| Logic Supply Range | 4.75–5.3V - ensures compatibility with standard 5V microcontroller I/O without level shifting |
Pinout & Package
UC3770AQTR is housed in a 28-pin PLCC (Q package) with gull-wing leads, thermally enhanced for motor drive applications. Pin 1–3, 9, 13–17, and 28 are ground terminals; Pins 4 and 12 connect to VM (motor supply); Pin 18 is VCC (logic supply); Pins 19 (I1), 20 (Phase), 21 (I0), and 23 (Current) provide digital control and current feedback interfaces.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pins 1–3, 9, 13–17, 28 | GND | Dedicated ground returns for logic, current sense, and power stages to minimize noise coupling |
| Pins 4, 12 | VM | High-current motor supply input - connects to external 10–45V DC bus with local bulk capacitance |
| Pin 18 | VCC | 5V logic supply - powers internal logic, comparators, and monostable timing circuitry |
| Pins 19, 21 | I1, I0 | Binary current select inputs - configure 3-level current threshold (400/255/80mV) for stepping resolution |
| Pin 20 | Phase | H-bridge direction control - sets AOUT/BOUT polarity to determine motor winding energization sequence |
| Pin 23 | Current | Current sense feedback node - connects to external sense resistor for closed-loop current regulation |
| Pin 10 | Comparator Input | Inputs scaled current sense voltage - compared against internal thresholds to trigger off-time monostable |
| Pin 11 | Timing | RT/CT connection - sets fixed off-time duration (25–35ms typical) for constant-current chopper control |
Key Features
| Feature | Design Value |
|---|---|
| Full/half/micro-step support | Enables precise position control in open-loop stepper systems without encoder feedback |
| LS-TTL compatible inputs | Direct interface with 5V microcontrollers and FPGAs without level-shifting circuitry |
| Integrated thermal shutdown | Prevents permanent damage during stall, short-circuit, or inadequate heatsinking |
| Programmable current thresholds | Three discrete current levels allow optimized torque/speed trade-offs per stepping mode |
| Soft intervention thermal response | Gradual current reduction before full shutdown maintains system stability during transient overloads |
Applications
| Industrial CNC Positioning | Automated Packaging Machinery |
|---|---|
Use Scenario: Precision linear actuation in multi-axis CNC routers using NEMA 23 stepper motors. IC Role / Device Role / Timing Role: Full-bridge driver executing micro-step commands from motion controller FPGA. Use Value: 2A drive capability and 80mV current threshold enable smooth 1/16-step resolution at 200 pulses/rev base step angle. | Use Scenario: Indexing conveyor belts and rotary feeders in high-speed packaging lines. IC Role / Device Role / Timing Role: Bipolar H-bridge controlling dual-winding stepper for synchronized cam motion. Use Value: 45V VM rating supports 36V industrial DC bus; thermal shutdown prevents downtime during jam-induced stall events. |
| Lab Automation Stage Control | Medical Imaging Sample Handling |
Use Scenario: XY translation stages in optical microscopy systems requiring sub-micron repeatability. IC Role / Device Role / Timing Role: Current-regulated stepper driver receiving step/direction signals from embedded ARM MCU. Use Value: Low saturation voltage (0.8V sink / 1.3V source) minimizes self-heating, preserving thermal stability during long dwell periods. | Use Scenario: Slide loader and specimen carousel positioning in automated histology scanners. IC Role / Device Role / Timing Role: Half-step configured driver delivering 71% holding torque with reduced audible vibration. Use Value: 255mV current threshold setting enables quiet, low-resonance operation critical for vibration-sensitive imaging environments. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar stepper motor driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| UC3717N | Integrated high-side clamp diodes; identical current sense thresholds (400/255/80mV); lower max VM (40V) | No external diodes required; limited to ≤40V motor supply; not rated for >2A continuous | Select UC3717N only if board layout lacks space for external diodes and motor voltage stays ≤40V |
| TB6600HG | Higher integration (built-in oscillator, microstep indexer); 4.5A peak output; requires 3.3V/5V logic; no thermal shutdown | Reduces external component count; supports up to 1/32 microstepping; needs external thermal management | Choose TB6600HG when higher current, finer microstepping, or simplified control interface is prioritized over thermal autonomy |
Compared with UC3770AQTR, UC3717N eliminates external diode requirements but sacrifices 5V headroom and 2A drive margin, while TB6600HG offers greater integration and resolution at the cost of autonomous thermal protection and discrete current threshold flexibility.
Availability
UC3770AQTR is available at Aetrix Electronics and suitable for industrial CNC positioning, automated packaging machinery, and lab automation stage control requiring stable component supply across extended production lifecycles.
Supply support for UC3770AQTR 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
Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and power management technologies, with decades of heritage in precision motor control ICs.
The UC3770A series was developed specifically for high-reliability open-loop stepper motor systems demanding robust current regulation, thermal resilience, and direct microprocessor interfacing without added complexity.
FAQ
What is the maximum motor supply voltage supported by UC3770AQTR?
The UC3770AQTR supports a motor supply voltage (VM) range of 10V to 45V, with absolute maximum rating at 50V. Operation above 45V risks exceeding specified electrical characteristics and may compromise reliability. For designs targeting 48V nominal rails, derating or additional overvoltage protection is recommended. The UC3770AQTR must be used within this 10–45V window to ensure compliance with its published saturation voltages, current thresholds, and thermal behavior.
Does UC3770AQTR require external high-side clamp diodes?
Yes, UC3770AQTR requires external high-side clamp diodes across each motor winding. Unlike the UC3717, it does not integrate these diodes. This design choice allows greater flexibility in diode selection (e.g., fast recovery, low VF) but mandates PCB layout space and correct polarity placement. Failure to install them risks destructive voltage spikes during current commutation. The UC3770AQTR datasheet explicitly states this requirement in both the description and application notes.
What current levels does UC3770AQTR support and how are they selected?
The UC3770AQTR supports three discrete current levels - 100%, 71%, and 50% of full-scale - selected via binary logic on pins I0 and I1. These correspond to internal comparator thresholds of 400mV, 255mV, and 80mV respectively. The selection directly determines chopper off-time and average winding current. This scheme enables deterministic full-step, half-step, and micro-step operation without analog DACs or external op-amps, making UC3770AQTR suitable for cost-sensitive, digitally controlled stepper systems.
Is UC3770AQTR pin-compatible with UC3717N?
No, UC3770AQTR is not pin-compatible with UC3717N. While both share functional similarity and matching current sense thresholds, UC3770AQTR uses a 28-pin PLCC (Q) package, whereas UC3717N uses a 16-pin DIP (N) or SOIC (J) package. Pin count, physical layout, and terminal assignments differ entirely. Drop-in replacement is only functional - not mechanical - and requires PCB redesign. The UC3770AQTR datasheet confirms distinct package diagrams and pin functions for each device family.
What is the operating temperature range for UC3770AQTR?
The UC3770AQTR is specified for ambient operation from 0°C to +70°C. Its thermal shutdown activates at +170°C junction temperature, providing protection beyond the rated ambient range. However, sustained operation near the upper ambient limit requires careful thermal design - including adequate copper area, optional heatsinking, and airflow - to maintain junction temperature below +150°C (absolute maximum). Derating curves in the UC3770AQTR datasheet show power dissipation limits versus ambient temperature.
UC3770AQTR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 28-LCC (J-Lead)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Output Configuration:
- Half Bridge (2)
- Applications:
- General Purpose, Stepper Motors
- Interface:
- Logic
- Load Type:
- Inductive
- Technology:
- Bipolar
- Rds On (Typ):
- -
- Current - Output / Channel:
- 2A
- Current - Peak Output:
- -
- Voltage - Supply:
- 4.75V ~ 5.3V
- Voltage - Load:
- 10V ~ 45V
- Operating Temperature:
- 0°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Features:
- -
- Fault Protection:
- Over Temperature
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-PLCC (11.51x11.51)
UC3770AQTR FAQ
1.How can I place an order for UC3770AQTR through Aetrix?
Please submit a Request for Quotation (RFQ) for UC3770AQTR 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 UC3770AQTR reliable?
The price and inventory of UC3770AQTR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for UC3770AQTR is usually 5 days.
3.What payment methods are accepted for UC3770AQTR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for UC3770AQTR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for UC3770AQTR?
UC3770AQTR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your UC3770AQTR 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 UC3770AQTR?
For technical support, including UC3770AQTR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your UC3770AQTR requirements.
6.How does Aetrix verify that UC3770AQTR is sourced from the original manufacturer or authorized distributors?
All UC3770AQTR 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 UC3770AQTR meets industry standards.
7.What is the process for return or replacement of UC3770AQTR?
All UC3770AQTR units undergo pre-shipment inspection (PSI). If there is an issue with UC3770AQTR, 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 UC3770AQTR part is unused and in its original packaging.
Return procedure for UC3770AQTR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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