A4973SLBTR-T - 1.5A Full-Bridge PWM Motor Driver | Allegro
MPN: A4973SLBTR-T ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $5.79 | $5.79 |
| 10 | $5.21 | $52.10 |
| 100 | $4.63 | $463.00 |
| 500 | $4.17 | $2,085.00 |
| 1,000 | $3.71 | $3,710.00 |
A4973SLBTR-T Overview
A full-bridge motor driver (also called an H-bridge) is a power-integrated circuit that uses four switching elements arranged in an H topology to drive a bidirectional DC current through a single inductive load, enabling forward, reverse, and braking control from a single IC. Within the broader taxonomy, this device is a motor driver -> motion/ignition controller -> power management IC -> semiconductor. PWM (pulse width modulation) current control regulates the average load current by switching the bridge transistors at high frequency with a variable duty cycle, balancing torque smoothness against switching losses.
Key features of the A4973SLBTR-T include internal fixed off-time PWM current-control circuitry, configurable fast and slow current-decay modes, a 3-bit DAC for current setpoint programming, a low-current sleep mode, and integrated protection such as thermal shutdown and crossover-current protection. Logic supply operates from 3 V to 5.5 V, allowing direct interface to 3.3 V or 5 V microcontrollers without level shifters. The wide 5 V to 50 V load supply range supports both 12 V/24 V industrial buses and higher-voltage applications.
The architecture combines DMOS power outputs with CMOS logic on a single BiMOS die. The fixed off-time PWM timer and synchronous rectification reduce power dissipation, while the exposed pad (EP) SOIC-16 package keeps junction temperature within safe limits at the 1.5 A continuous rating when the PCB copper pour is sized appropriately. Internal logic handles shoot-through protection and cross-conduction lockout, simplifying firmware and reducing external component count.
Typical applications include DC brushed motor control in printers, scanners, point-of-sale equipment, textile machines, and small industrial automation modules. The integrated 3-bit DAC and sleep mode also suit battery-powered actuators where standby current matters. When laying out the PCB, keep the high-current load return path short and stitch the EP to a continuous ground copper pour. Observe the 50 V absolute-maximum load supply and add a low-ESR bypass capacitor close to the VBB pin to suppress switching transients.
Drop-in alternatives for A4973SLBTR-T — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with A4973SLBTR-T (same form factor and footprint) — differing in Continuous Output Current, Motor Type, Number of Outputs, Output Configuration, Package.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
A4973SB-T
✅ Drop-In📋 Reference alternative (not in catalog)
A3982SLBTR-T
✅ Drop-In✓ In Stock
$4.63 / Unit
View Datasheet →A4973SLBTR-T Maximum Ratings & Electrical Characteristics
| Motor Type | Brushed DC |
| Output Configuration | Full-Bridge (H-Bridge), 1 bridge |
| Number of Outputs | 2 (half-bridge pair forming 1 full bridge) |
| Continuous Output Current | ±1.5 A |
| Load Supply Voltage (VBB) | 5 V to 50 V |
| Logic Supply Voltage (VCC) | 3 V to 5.5 V |
| Current Control | Internal fixed off-time PWM with 3-bit DAC setpoint |
| Current-Decay Modes | Fast and slow decay, user-selectable |
| Sleep Mode | Yes (low quiescent current) |
| Protection Features | Thermal shutdown, crossover-current protection |
| Operating Temperature | -20 C to +85 C |
| Package | 16-pin SOIC Wide Body (SLB) with exposed thermal pad |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant |
A4973SLBTR-T Pin Configuration
| Pin 1 | VBB — Load supply voltage (5 V to 50 V) |
| Pin 2 | PHASE — Logic input - direction control |
| Pin 3 | ENABLE — Logic input - bridge enable, active high |
| Pin 4 | SLOW — Logic input - selects fast or slow current decay |
| Pin 5 | RC — R/C network sets fixed off-time PWM period |
| Pin 6 | REF — Reference voltage input for current DAC |
| Pin 7 | D0 — DAC bit 0 input |
| Pin 8 | D1 — DAC bit 1 input |
| Pin 9 | D2 — DAC bit 2 input |
| Pin 10 | GND — Logic and power ground |
| Pin 11 | SENSE — Current-sense resistor connection |
| Pin 12 | OUT2 — Bridge output 2 |
| Pin 13 | VBB — Load supply voltage (pin strap to pin 1) |
| Pin 14 | OUT1 — Bridge output 1 |
| Pin 15 | VCP — Charge pump capacitor |
| Pin 16 | VCC — Logic supply (3 V to 5.5 V) |
Typical Applications
A4973SLBTR-T is suitable for 7 applications: Brushed DC Motor Drive in Printers and Scanners, Point-of-Sale (POS) Printer and Cash Drawer Actuator, Textile and Sewing Machine Drive, Small Industrial Automation Modules, Battery-Powered Robotics and Toys, Automotive Accessories and HVAC Actuators, Vending and Coffee Machine Pump Motors.
Brushed DC Motor Drive in Printers and Scanners
The A4973SLBTR-T fits printer and scanner paper-feed, carriage, and roller motors because of its ±1.5 A continuous output and 50 V VBB rating, which comfortably covers the 24 V bus typical in these machines. The internal fixed off-time PWM current control eliminates the need for an external chopping circuit, reducing the BOM by several components. Per the Allegro datasheet the 3-bit DAC allows the MCU to command one of 8 current setpoints via three GPIO lines, simplifying firmware for multi-motor boards. The exposed-pad SOIC-16 wide-body package keeps junction temperature low even when four motors run simultaneously.
Recommended
Point-of-Sale (POS) Printer and Cash Drawer Actuator
POS printers use small brushed DC motors for paper advance, cutter drive, and receipt feed; the A4973SLBTR-T handles these loads with its 1.5 A continuous rating and integrated thermal shutdown. The sleep mode reduces quiescent current between transactions, helping battery-backed POS terminals meet standby budgets. Fast/slow current-decay selection, configurable via the SLOW pin per the Allegro datasheet, lets engineers tune audible noise versus torque ripple. The 3 V to 5.5 V logic interface is compatible with common POS host MCUs without level shifters.
Recommended
Textile and Sewing Machine Drive
Industrial sewing and embroidery machines demand bidirectional motor control with precise current limiting to avoid breaking needles - exactly the use case the A4973SLBTR-T targets. The fixed off-time PWM current-control loop holds the maximum load current to the value set by the 3-bit DAC and external sense resistor, protecting the motor windings. With a 50 V VBB rating the IC also supports higher-voltage bobbins and thread-trimmer actuators. The exposed thermal pad allows sustained 1.5 A operation in the warm enclosures typical of textile equipment.
Recommended
Small Industrial Automation Modules
For 24 V brushed DC servo motors driving valves, dampers, and small conveyor sections, the A4973SLBTR-T delivers ±1.5 A continuous output from the same 24 V bus that powers the rest of the module. Internal crossover-current protection eliminates shoot-through that would otherwise shorten the bridge transistors. The PHASE and ENABLE inputs let the MCU command direction and coast/brake without additional glue logic. Operating temperature of -20 C to +85 C suits most factory-floor enclosures without derating.
Recommended
Battery-Powered Robotics and Toys
Robotics kits and educational toys running from 2S-3S Li-Ion packs (6 V to 12.6 V) sit comfortably inside the A4973SLBTR-T's 5 V to 50 V VBB window. The low-current sleep mode is critical for battery life when the robot is idle. Per the Allegro datasheet the internal synchronous rectification reduces on-state losses, extending run-time. The 3-bit DAC current programming lets a low-pin-count MCU command torque settings without a true DAC peripheral, keeping the BOM and cost low.
Recommended
Automotive Accessories and HVAC Actuators
Although not AEC-Q100 qualified, the A4973SLBTR-T is used in non-safety automotive accessories such as headlamp levelers, mirror adjusters, and HVAC blend-door actuators where the load draws under 1.5 A at 12 V. Internal thermal shutdown protects against stalled-motor conditions common in cold weather. The 50 V VBB rating provides margin against load-dump transients when paired with an external TVS clamp. Designers must verify EMC compliance against OEM-specific standards before deployment.
Recommended
Vending and Coffee Machine Pump Motors
Vending machines and coffee brewers use brushed DC pumps and auger motors that need bidirectional control with current limiting to avoid stalling. The A4973SLBTR-T's 3-bit DAC setpoint and internal PWM current control let the host MCU command a torque limit and walk away, with the IC chopping the current automatically. The exposed-pad SOIC-16 wide-body handles the continuous load of auger motors that run for many seconds at a time. The sleep mode reduces standby current between vends, important for energy-star compliance.
Recommended
Recommended Products Summary
Engineering reference data for A4973SLBTR-T — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | A4973SB-T | A3982SLBTR-T |
|---|---|---|---|
| Package | SOIC-16 wide body (SLB) with EP | SOIC-16 narrow body, no EP | SOIC-16 wide body (SLB) with EP - same |
| Brand | Allegro MicroSystems | Allegro MicroSystems | Allegro MicroSystems |
| Motor Type | Brushed DC (single H-bridge) | Brushed DC | Bipolar stepper (dual H-bridge) |
| Continuous Output Current | ±1.5 A | ±1.5 A | ±1.5 A per bridge |
| Load Supply Voltage (VBB) | 5 V to 50 V | 5 V to 50 V | 5 V to 50 V |
| Logic Supply (VCC) | 3 V to 5.5 V | 3 V to 5.5 V | 3 V to 5.5 V |
| Current Control | Internal fixed off-time PWM + 3-bit DAC | Internal fixed off-time PWM + 3-bit DAC | Internal PWM with microstepping logic |
| Sleep Mode | Yes | Yes | Yes |
| Lifecycle Status | Active | Discontinued (July 2018) | Active |
| Exposed Thermal Pad | Yes | No | Yes |
Key Differentiators
- Exposed-pad SOIC-16 package sustains full 1.5 A continuous (vs A4973SB-T)
- Single full-bridge optimized for brushed DC, not steppers (vs A3982SLBTR-T)
- Integrated 3-bit DAC current setpoint vs external DAC (vs Discrete H-bridge + external op-amp)
Design Notes
The A4973SLBTR-T dissipates significant power at high currents. Estimated: at VBB=24 V, VOUT=12 V (half-bridge, average), and 1.5 A continuous load, each output transistor dissipates roughly (24-12)*1.5 = 18 W peak and several watts average depending on PWM duty cycle. The exposed pad must be soldered to a continuous ground copper pour of at least 1 square inch (645 mm^2) on the top and bottom layers stitched with thermal vias. Without the EP the part cannot sustain 1.5 A continuous - this is the primary reason the legacy A4973SB-T (no EP) was discontinued.
Place a 100 nF ceramic bypass capacitor as close as possible to the VBB pin (pin 1) and a 100 uF aluminum-polymer or tantalum bulk capacitor on the same node to absorb motor back-EMF. Per the Allegro datasheet the VCC logic supply requires a 100 nF bypass close to pin 16. The SENSE resistor should use a Kelvin connection to GND to avoid ground-bounce errors. Keep the high-current OUT1/OUT2 traces short and wide, and route the logic signals (PHASE, ENABLE, D0-D2) away from the switching node to avoid capacitive coupling.
Do not exceed the 50 V absolute-maximum rating on VBB even transiently - inductive kickback from the motor can exceed 50 V if a flyback diode is omitted. The internal dead time and crossover-current protection reduce but do not eliminate shoot-through; never command both PHASE and the inverse PHASE simultaneously in firmware. The RC pin sets the fixed off-time (t_off = R*C); a too-small RC value increases switching losses while a too-large value creates audible current ripple. Verify the 3-bit DAC truth table against your firmware - the code-to-current mapping is not binary-weighted in all Allegro A4973 datasheet revisions.
Compliance Information
RoHS and lead-free per Allegro product page. AEC-Q100 qualification not stated; the legacy A4973 family is industrial/consumer grade. For automotive, evaluate Allegro A4953 or ON Semi NCV7720.
