My Inquiry
My Account
Texas Instruments UC3770AQ
- Part No.:
- UC3770AQ
- Manufacturer:
- Texas Instruments
- Category:
- Full Half-Bridge (H Bridge) Drivers
- Package:
- 28-LCC (J-Lead)
- Datasheet:
-
UC3770AQ.pdf
- Description:
- IC HALF BRIDGE DRIVER 2A 28PLCC
- Quantity:
- Payment:
- Shipping:
Inventory:2,419
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
UC3770AQ from Texas Instruments is a high-performance bipolar stepper motor full-bridge driver IC with LS-TTL-compatible logic inputs, integrated current sense and thermal shutdown. It delivers up to 2A output current, supports 10–45V motor supply (VM), and enables full-step, half-step, and micro-step operation in industrial motion control systems.
For engineers reviewing the UC3770AQ datasheet, UC3770AQ pinout, UC3770AQ application, or UC3770AQ equivalent, key selection criteria include its 400–430mV current-sense threshold (I₀=L, I₁=L), 25–35ms programmable off-time via RT/CT, ±2A output capability, and requirement for external high-side clamp diodes in H-bridge configurations.
Technical Context
The UC3770AQ implements a monostable-controlled current-regulated H-bridge with dual NPN/PNP output stages, where sink and source saturation voltages are separately specified (e.g., 0.8V at 1.0A sink, 1.3V at 1.0A source). Its comparator-based current sensing uses pin 10 with three selectable thresholds (70–430mV) determined by logic states on pins 20 (Phase), 21 (I₀), and 19 (I₁).
Thermal protection triggers at +170°C junction temperature with soft intervention, and operation is limited to 0°C to +70°C ambient. Unlike UC3717, UC3770AQ requires external high-side clamp diodes due to absence of internal clamping-critical for inductive kickback management in bipolar stepper windings.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current | ±2A continuous - drives NEMA 17–23 bipolar stepper motors directly |
| Motor Supply Voltage (VM) | 10–45V - supports 12V, 24V, and 42V industrial motor rails |
| Logic Supply (VCC) | 4.75–5.3V - compatible with standard 5V TTL/CMOS controllers |
| Current Sense Threshold | 400–430mV (I₀=L, I₁=L) - sets nominal full-scale current with external sense resistor |
| Off-Time Programmability | 25–35ms (RT=56kΩ, CT=820pF) - determines chopper frequency and thermal duty cycle |
| Sink Saturation Voltage | 0.8V at 1.0A - limits conduction loss in low-side switching path |
| Source Saturation Voltage | 1.3V at 1.0A - defines upper-bound voltage drop in high-side drive path |
Pinout & Package
UC3770AQ is housed in a 28-pin PLCC (Q package) with exposed thermal pad. Pin 1–3, 9, 13–17, and 28 are ground terminals for low-inductance return paths; VM connects to pins 4 and 12; VCC is on pin 18; and current-sense reference VR is on pin 24.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pins 1–3, 9, 13–17, 28 | GND | Dedicated ground returns for power, logic, and current sense-minimizes noise coupling |
| Pins 4, 12 | VM | Motor supply input-dual connection reduces trace inductance for high-current switching |
| Pin 18 | VCC | 5V logic supply-powers internal comparators, monostable, and gate drivers |
| Pins 7, 8, 9 | Logic Inputs (I₀, Phase, I₁) | LS-TTL-compatible step/direction/control interface-no level-shifting needed |
| Pin 10 | Current Sense Input | Comparator input referenced to VR-accepts mV-level sense voltage from external resistor |
| Pin 24 | VR | Reference voltage input for current comparator-sets scaling for sense threshold |
| Pins 6, 10 | AOUT / BOUT | H-bridge outputs-drive complementary stepper winding terminals with ±2A capability |
Key Features
| Feature | Design Value |
|---|---|
| Three-step current control | Selects 50%, 71%, or 100% full-scale current via I₀/I₁ logic-enables precise torque management in half-step mode |
| Programmable off-time | Set by external RT/CT network-adjusts chopper frequency to balance efficiency, EMI, and thermal rise |
| Thermal shutdown with soft intervention | Triggers at +170°C junction temp-reduces output current gradually instead of abrupt shutdown |
| External high-side clamp diode support | Requires discrete fast-recovery diodes across VM–AOUT/BOUT-enables robust inductive energy recirculation |
| LS-TTL logic compatibility | Accepts 0.8V/2.0V thresholds and ±400µA input current-direct interface with microcontrollers and FPGA I/O |
Applications
| Industrial CNC Positioning | Automated Laboratory Equipment |
|---|---|
Use Scenario: Precision open-loop positioning of X-Y stages in benchtop CNC mills using 1.8° bipolar stepper motors. IC Role / Device Role / Timing Role: Full-bridge driver executing micro-stepped commutation under microcontroller direction; regulates phase current via chopper control. Use Value: Enables 1/8- and 1/16-step resolution with stable 2A peak current-reducing resonance and improving positional accuracy without closed-loop feedback. | Use Scenario: Automated pipetting and slide scanning in diagnostic analyzers requiring repeatable, low-vibration motion. IC Role / Device Role / Timing Role: Bipolar H-bridge controller managing dual-axis stepper actuators with synchronized start/stop and acceleration profiles. Use Value: Soft thermal intervention prevents sudden axis stall during extended duty cycles-maintaining assay integrity and system uptime. |
| 3D Printer Extruder Control | Factory Automation Indexers |
Use Scenario: Driving extruder stepper motors in fused deposition modeling (FDM) printers operating at ambient temperatures up to 60°C. IC Role / Device Role / Timing Role: Current-regulated motor driver accepting step/direction signals from motion controller; manages winding current decay via off-time tuning. Use Value: 10–45V VM range accommodates 24V printer main rails; 25–35ms off-time prevents overheating during sustained extrusion moves. | Use Scenario: Indexing rotary tables in packaging lines requiring high-torque, intermittent motion with rapid direction reversal. IC Role / Device Role / Timing Role: High-current H-bridge stage translating PLC-generated step pulses into bidirectional winding excitation. Use Value: ±2A output sustains holding torque during dwell periods; external clamp diodes suppress voltage spikes during 100ms direction changes. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bipolar stepper motor driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TB6600HG | Integrated current DAC, no external RT/CT required; higher max VM (45V); built-in microstepping logic | Reduces external component count but lacks UC3770AQ's programmable off-time flexibility and thermal soft-intervention behavior | Preferred for simplified designs where fixed microstepping and lower BOM cost outweigh fine-grained chopper tuning needs |
| LV8729V | 5V-only logic supply; integrated FETs; max output current 2.5A; includes stall detection and PWM control | Eliminates need for external MOSFETs and clamp diodes-but requires redesign of power stage layout and gate drive circuitry | Best suited when upgrading from discrete-driver architectures to fully integrated solutions with embedded diagnostics |
Compared with TB6600HG and LV8729V, UC3770AQ offers field-programmable chopper timing and explicit thermal soft intervention-valuable in thermally constrained enclosures where gradual current rollback preserves motion continuity during transient overload.
Availability
UC3770AQ is available at Aetrix Electronics and suitable for industrial CNC positioning, automated laboratory equipment, and 3D printer extruder control requiring stable component supply and long-term obsolescence management.
Supply support for UC3770AQ 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 company headquartered in Dallas, Texas, delivering analog, embedded processing, and logic products for industrial, automotive, and communications markets.
The UC3770A series belongs to TI's legacy motor driver portfolio, designed specifically for high-current, current-regulated bipolar stepper motor control in cost-sensitive industrial motion systems.
FAQ
What is the maximum motor supply voltage supported by UC3770AQ?
The UC3770AQ supports a motor supply voltage (VM) range of 10V to 45V, with absolute maximum rating at 50V. Operation above 45V risks exceeding safe operating area limits and may trigger premature thermal shutdown. For reliable 42V rail use-common in industrial motor systems-the UC3770AQ remains within specification when ambient temperature stays below +70°C and PCB thermal design meets Unitrode's recommended copper pour guidelines.
Does UC3770AQ include internal clamp diodes for inductive kickback protection?
No, UC3770AQ does not integrate high-side clamp diodes. Unlike earlier UC3717, it requires external fast-recovery diodes connected between VM and each output (AOUT/BOUT) to safely recirculate inductive energy during current decay. This design choice reduces die size and allows optimization of diode speed and voltage rating per application-critical for minimizing voltage overshoot in high-L stepper windings.
How is current regulation implemented in UC3770AQ?
UC3770AQ uses a comparator-based chopper architecture: the voltage across an external sense resistor is fed to pin 10, compared against a reference derived from VR (pin 24) and scaled by logic states on pins 19 (I₀), 20 (Phase), and 21 (I₁). When sensed voltage exceeds the selected threshold (e.g., 400–430mV), the monostable triggers off-time-turning off both bridge legs until the timer expires. This cycle repeats to maintain average current.
What is the purpose of the VR pin on UC3770AQ?
The VR pin (pin 24) provides the reference voltage for the internal current-sense comparator. It accepts up to 15V input and scales the comparator threshold-so a 5V VR yields nominal thresholds of 400–430mV, while lower VR values proportionally reduce all three current levels (100%, 71%, 50%). This enables precise current calibration across temperature and unit variance without changing the sense resistor.
Can UC3770AQ be used for unipolar stepper motor control?
No, UC3770AQ is designed exclusively for bipolar stepper motor winding control. Its H-bridge topology requires four-quadrant current flow through each winding-unlike unipolar drivers that use center-tapped windings and single-direction current. Attempting unipolar use would result in incorrect commutation, excessive heating, and potential device failure due to mismatched current paths and missing mid-winding tap interface.
UC3770AQ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 28-LCC (J-Lead)
- Packaging:
- Tube
- 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)
UC3770AQ FAQ
1.How can I place an order for UC3770AQ through Aetrix?
Please submit a Request for Quotation (RFQ) for UC3770AQ 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 UC3770AQ reliable?
The price and inventory of UC3770AQ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for UC3770AQ is usually 5 days.
3.What payment methods are accepted for UC3770AQ?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for UC3770AQ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for UC3770AQ?
UC3770AQ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your UC3770AQ 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 UC3770AQ?
For technical support, including UC3770AQ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your UC3770AQ requirements.
6.How does Aetrix verify that UC3770AQ is sourced from the original manufacturer or authorized distributors?
All UC3770AQ 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 UC3770AQ meets industry standards.
7.What is the process for return or replacement of UC3770AQ?
All UC3770AQ units undergo pre-shipment inspection (PSI). If there is an issue with UC3770AQ, 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 UC3770AQ part is unused and in its original packaging.
Return procedure for UC3770AQ:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
UC3770AQ Tags
-
NCP1393BDR2G
onsemi
-
A3909GLNTR-T
Allegro MicroSystems
-
NCP51530BDR2G
onsemi
-
A3909GLYTR-T
Allegro MicroSystems
-
SIC631CD-T1-GE3
Vishay Siliconix
-
BTN70301EPAXUMA1
Infineon Technologies
-
TDA21520AUMA1
Infineon Technologies
-
AOZ5116QI
Alpha & Omega Semiconductor Inc.
-
IRSM005-301MHTR
Infineon Technologies
-
IRSM005-301MH
Infineon Technologies
-
MP6610GJ-Z
Monolithic Power Systems Inc.
-
DRV8908QPWPRQ1
Texas Instruments
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
