Part A
A3977SLPTR-T
Allegro MicroSystems
- Lifecycle
- Active
- Stock
- 3008 PCS
- Package
- TSSOP-28
- Series
- PMIC - Motor Drivers, Controllers
Replacement verdict
Compatible functional replacement candidate
The A3977SLPTR-T and A3977SLPTR are functionally equivalent DMOS microstepping driver ICs from Allegro MicroSystems, sharing identical silicon design, electrical characteristics, and thermal performance. The only distinction is the packaging suffix, where the "-T" designation indicates tape-and-reel packaging versus the standard tube or tray format. Both devices are drop-in compatible for PCB assembly, with the same 44-pin TSSOP exposed pad footprint and pin configuration. Designers can substitute either variant without circuit redesign, provided the board assembly process accommodates the respective packaging format.
Package Type
High match
Pin Configuration
High match
Electrical Characteristics
High match
Operating Temperature Range
High match
Parts at a glance
Part B
A3977SLPTR
Allegro MicroSystems
- Lifecycle
- Active
- Stock
- 5991 PCS
- Series
- Power Management (PMIC) - Motor Drivers, Controllers
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | A3977SLPTR-T | A3977SLPTR | Why it matters |
|---|---|---|---|
| Manufacturer | Allegro MicroSystems | Allegro MicroSystems | Same manufacturer ensures consistent design, documentation, and quality standards. |
| Product Category | Motor Driver ICs - Stepper | Motor Driver ICs - Stepper | Confirms both parts serve the same functional role as stepper motor drivers. |
| Package / Case | 28-TSSOP (0.173", 4.40mm Width) Exposed Pad | 28-TSSOP (0.173", 4.40mm Width) Exposed Pad | Identical package allows drop-in replacement on the same PCB footprint. |
| Mounting Type | Surface Mount | Surface Mount | Same mounting method ensures mechanical compatibility in assembly. |
| Supply Voltage Range | 3 V to 5.5 V | 3 V to 5.5 V | Matching logic supply range ensures compatibility with the same control circuitry. |
| Output Current | Up to 2.5 A | Up to 2.5 A | Same current rating means equivalent drive capability for the stepper motor. |
| Operating Temperature Range | -20°C to +85°C | -20°C to +85°C | Identical thermal range ensures the same environmental operating limits. |
| Motor Type | Bipolar Stepper | Bipolar Stepper | Confirms both devices drive the same motor type, ensuring functional equivalence. |
| Microstepping Resolution | Full, 1/2, 1/4, 1/8 step | Full, 1/2, 1/4, 1/8 step | Same microstepping options preserve motion smoothness and positioning accuracy. |
| Packaging / Ordering Suffix | Tape & Reel (T suffix) | Tape & Reel | The -T suffix denotes tape and reel packaging; both are supplied in tape and reel, so handling and assembly are equivalent. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | A3977SLPTR-T | A3977SLPTR |
|---|---|---|
| Part Status | Active | Obsolete |
| Motor Type - Stepper | Bipolar | Bipolar |
| Function | Driver - Fully Integrated, Control and Power Stage | Driver - Fully Integrated, Control and Power Stage |
| Output Configuration | Half Bridge (4) | Half Bridge (4) |
| Interface | Logic | Logic |
| Technology | DMOS | DMOS |
| Step Resolution | 1, 1/2, 1/4, 1/8 | 1, 1/2, 1/4, 1/8 |
| Applications | General Purpose | General Purpose |
| Current - Output | 2.5A | 2.5A |
| Voltage - Supply | 3V ~ 5.5V | 3V ~ 5.5V |
| Voltage - Load | 8V ~ 35V | 8V ~ 35V |
| Operating Temperature | -20°C ~ 150°C (TJ) | -20°C ~ 150°C (TJ) |
| Mounting Type | Surface Mount | Surface Mount |
| Base Product Number | - | A3977 |
Frequently asked questions
What is the difference between the A3977SLPTR-T and the A3977SLPTR?
The A3977SLPTR-T and A3977SLPTR are the same Allegro MicroSystems DMOS microstepping driver IC in a 44-lead TSSOP package (suffix LP). The "-T" suffix denotes tape-and-reel packaging per Allegro's ordering nomenclature, while the base part number A3977SLPTR is the same device and package. Both share identical electrical, thermal, and functional specifications; the difference is the shipping/packaging designation.
Are the A3977SLPTR-T and A3977SLPTR electrically and functionally identical?
Yes. Both variants use the same A3977 die and the same 44-pin TSSOP (LP) package. Rated supply voltage, output current, logic interface, microstepping options, and internal protection features are identical because the "-T" only designates tape-and-reel packing.
What is the maximum output current rating of the A3977SLPTR-T and A3977SLPTR?
Per the Allegro A3977 datasheet, the device is rated for 2.5 A maximum output current per bridge (peak) and 1.5 A continuous per bridge at appropriate thermal conditions. Actual continuous current depends on PCB copper area, ambient temperature, and heatsinking.
What supply voltage range do the A3977SLPTR-T and A3977SLPTR support?
The A3977 operates from a motor supply (load supply) of 8 V to 35 V, with a logic supply (VDD) of 3.0 V to 5.5 V, as specified in the Allegro datasheet. These limits apply equally to both the -T and non-T ordering variants.
What microstepping resolutions are supported by the A3977SLPTR-T and A3977SLPTR?
The A3977 supports full-step, half-step, quarter-step, and eighth-step microstepping, selectable via the MS1 and MS2 logic inputs. This functionality is identical for both the A3977SLPTR-T and A3977SLPTR.
Can the A3977SLPTR-T be used as a drop-in replacement for the A3977SLPTR?
Yes, because both are the same device in the same 44-lead TSSOP package with identical pinout and specifications. The only difference is the tape-and-reel packaging indicated by the "-T" suffix, so no electrical or layout changes are required.
What protection features are integrated into the A3977SLPTR-T and A3977SLPTR?
The A3977 includes internal fixed off-time PWM current control, crossover-current protection, undervoltage lockout (UVLO), and thermal shutdown. These integrated protection features are identical in both the A3977SLPTR-T and A3977SLPTR.
What package and pin count do the A3977SLPTR-T and A3977SLPTR use?
Both variants are supplied in a 44-lead TSSOP (thin shrink small outline package) with exposed thermal pad, designated by the "LP" suffix in the part number. Pin count, pinout, and thermal pad configuration are identical between the two ordering codes.