Part A
A3977SLPTR-T
Allegro MicroSystems
- Lifecycle
- Active
- Stock
- 3008 Stückzahl
- Package
- TSSOP-28
- Series
- PMIC Motor Treiber, Controller
Replacement verdict
Compatible functional replacement candidate
The A3977SLPTR-T and A3977KLP are functionally equivalent DMOS microstepping driver ICs from the same Allegro A3977 family, sharing identical electrical ratings, logic interface, and output drive capability. The primary distinction is the operating temperature range and package thermal performance, making the A3977SLPTR-T a viable replacement for the A3977KLP in most applications where the extended temperature range is not mandatory.
Output Current Rating
High match
Supply Voltage Range
High match
Package Type
High match
Operating Temperature Range
Validation required
Parts at a glance
Part B
A3977KLP
Allegro MicroSystems
- Lifecycle
- Active
- Stock
- 9325 Stückzahl
- Package
- TSSOP-28
- Series
- PMIC Motor Treiber, Controller
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 | A3977KLP | Why it matters |
|---|---|---|---|
| Manufacturer | Allegro MicroSystems | Allegro MicroSystems | Same manufacturer ensures consistent design lineage and documentation. |
| Product Category | Motor Driver ICs | Motor Driver ICs | Confirms both parts serve the same functional role in a circuit. |
| Motor Type | Bipolar Stepper | Bipolar Stepper | Both must drive the same motor type to be functionally interchangeable. |
| Output Current per Channel | 2.5 A | 2.5 A | Current rating determines the maximum load the driver can handle. |
| Supply Voltage Range | 3 V to 5.5 V | 3 V to 5.5 V | Operating voltage must match the system power rail for compatibility. |
| Output Voltage Range | 8 V to 35 V | 8 V to 35 V | Defines the motor supply voltage the driver can support. |
| Mounting Type | Surface Mount | Through Hole | Mounting style affects PCB layout and assembly process compatibility. |
| Package / Case | 28-TSSOP (0.173", 4.40mm Width) Exposed Pad | 28-DIP (0.600", 15.24mm) | Different packages require different PCB footprints and cannot be drop-in replaced. |
| Operating Temperature | -20°C to 85°C (TA) | -40°C to 125°C (TA) | Temperature range determines suitability for industrial vs. commercial environments. |
| Packaging | Tape & Reel (TR) | Tube | Packaging affects handling and is tied to the assembly method used. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | A3977SLPTR-T | A3977KLP |
|---|---|---|
| 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) | -40°C ~ 150°C (TJ) |
| Mounting Type | Surface Mount | Surface Mount |
Frequently asked questions
What are the key differences between the A3977SLPTR-T and the A3977KLP?
The A3977SLPTR-T and A3977KLP are both Allegro MicroSystems A3977 DMOS microstepping driver ICs with built-in translators. The primary differences are the operating temperature range and packaging format. The A3977SLPTR-T is specified for an ambient temperature range of -20°C to +85°C and is supplied in a 28-lead TSSOP package with exposed thermal pad, delivered on tape and reel. The A3977KLP is specified for an ambient temperature range of -40°C to +125°C and is supplied in a 28-lead TSSOP package with exposed thermal pad in tube form. The "K" grade denotes the wider temperature range, while the "S" grade denotes the standard temperature range.
Are the A3977SLPTR-T and A3977KLP electrically and functionally interchangeable?
Yes, both devices share the same functional core: a 35 V, ±2.5 A DMOS full-bridge driver with a built-in microstepping translator, fixed off-time current control, and logic supply range of 3.0 V to 5.5 V. They have identical pinouts and the same 28-lead TSSOP with exposed thermal pad footprint. The only differences are the temperature grade and the shipping media (tape and reel versus tube). Therefore, they are functionally interchangeable provided the application's ambient temperature requirements are satisfied by the selected grade.
What is the maximum output current rating for the A3977SLPTR-T and A3977KLP?
Both the A3977SLPTR-T and A3977KLP are rated for a maximum continuous output current of ±2.5 A per bridge, with a peak output current of ±2.5 A. The actual achievable current depends on the thermal management of the PCB, the ambient temperature, and the duty cycle. Allegro MicroSystems datasheet specifications should be consulted for derating curves under specific operating conditions.
What is the operating voltage range for the A3977SLPTR-T and A3977KLP?
Both devices operate from a motor supply voltage (VBB) of 8 V to 35 V. The logic supply voltage (VDD) range is 3.0 V to 5.5 V. These ratings are identical for both the A3977SLPTR-T and the A3977KLP, as they share the same silicon design and differ only in temperature grade and packaging media.
Can the A3977SLPTR-T be used as a drop-in replacement for the A3977KLP in an existing design?
Yes, the A3977SLPTR-T can be used as a drop-in replacement for the A3977KLP in terms of package footprint, pinout, and electrical function, because both are 28-lead TSSOP with exposed thermal pad and share identical pin assignments. However, the A3977SLPTR-T has a narrower ambient temperature range of -20°C to +85°C compared to the A3977KLP's -40°C to +125°C. The replacement is only valid if the application's operating ambient temperature remains within the A3977SLPTR-T's specified range. Additionally, the shipping media differs (tape and reel versus tube), which may affect automated assembly processes.
What microstepping resolutions are supported by the A3977SLPTR-T and A3977KLP?
Both the A3977SLPTR-T and A3977KLP support full-step, half-step, quarter-step, and eighth-step microstepping resolutions, selectable via the MS1 and MS2 logic inputs. This is a core feature of the A3977 translator and is identical across both temperature grades.
What thermal management considerations apply when comparing the A3977SLPTR-T and A3977KLP?
Both devices are supplied in the same 28-lead TSSOP package with an exposed thermal pad, which must be soldered to a PCB copper area for heat dissipation. The A3977KLP, with its wider temperature range of -40°C to +125°C, is intended for harsher environments and may require more robust thermal design to maintain junction temperature within limits at higher ambient temperatures. The A3977SLPTR-T, rated for -20°C to +85°C, is suitable for standard commercial and industrial environments. In both cases, the datasheet's thermal resistance and power dissipation curves should be used to size the thermal pad and copper area appropriately.
Are the A3977SLPTR-T and A3977KLP RoHS compliant?
Allegro MicroSystems lists both the A3977SLPTR-T and A3977KLP as RoHS-compliant and halogen-free, in accordance with the manufacturer's environmental specifications. The "-T" suffix on A3977SLPTR-T indicates tape-and-reel packaging, while the A3977KLP is supplied in tube packaging. Designers should verify the latest compliance documentation from Allegro MicroSystems or authorized distributors such as DigiKey or Mouser for the most current environmental status.