Part A
A3977SLPTR-T
Allegro 마이크로시스템
- Lifecycle
- Active
- Stock
- 3008 PCS
- Package
- TSSOP-28
- Series
- PMIC - 모터 드라이브, 컨트롤러
Replacement verdict
Compatible functional replacement candidate
The A3977SLPTR-T and A3977KLP-T are functionally equivalent DMOS microstepping driver ICs from Allegro MicroSystems, sharing identical electrical ratings, logic interface, and output drive capability. The primary distinction lies in their operating temperature range and package thermal characteristics, making the A3977SLPTR-T a viable replacement for the A3977KLP-T in most applications where the extended temperature range of the K-grade variant is not mandatory. Designers should verify thermal margin and ambient temperature requirements before substituting.
Output Current Rating
High match
Supply Voltage Range
High match
Operating Temperature Range
Validation required
Package Type
High match
Parts at a glance
Part B
A3977KLP-T
Allegro 마이크로시스템
- Lifecycle
- Active
- Stock
- 9857 PCS
- Package
- TSSOP-28
- Series
- PMIC - 모터 드라이브, 컨트롤러
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-T | Why it matters |
|---|---|---|---|
| Operating Temperature Range | -20°C to +85°C | -40°C to +125°C | Determines the ambient temperature range in which the device can reliably operate; the K-grade part supports harsher environments. |
| Product Grade / Qualification | Commercial grade | Automotive/industrial grade | Grade affects qualification testing, reliability screening, and suitability for automotive or industrial applications. |
| Packaging / Reel Option | Tape and reel (TR suffix) | Tube / bulk | Packaging determines compatibility with automated pick-and-place assembly lines versus manual or low-volume handling. |
| Output Current Rating | ±2.5 A (peak) | ±2.5 A (peak) | Defines the maximum current the driver can deliver to the stepper motor windings, directly affecting torque capability. |
| Supply Voltage Range | 8 V to 35 V | 8 V to 35 V | Sets the allowable motor supply voltage window for proper operation of the DMOS driver stage. |
| Package Type | 28-pin TSSOP (LP) | 28-pin TSSOP (LP) | Package footprint and thermal characteristics must match the PCB layout for drop-in substitutability. |
| Microstepping Resolution | Full, half, quarter, eighth step | Full, half, quarter, eighth step | Determines achievable motion smoothness and positional resolution in stepper motor control. |
| Internal PWM Current Control | Fixed off-time PWM with adjustable current | Fixed off-time PWM with adjustable current | Affects current regulation accuracy and motor heating; identical behavior ensures equivalent drive performance. |
Need help validating a replacement?
Send your BOM and application constraints for technical and sourcing review.
Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | A3977SLPTR-T | A3977KLP-T |
|---|---|---|
| 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 A3977KLP-T?
The A3977SLPTR-T and A3977KLP-T are both Allegro MicroSystems A3977 DMOS microstepping driver ICs with built-in translators. The primary difference is their operating temperature range and corresponding qualification: the A3977SLPTR-T is rated for the commercial/industrial temperature range of -20°C to +85°C, while the A3977KLP-T is rated for the automotive temperature range of -40°C to +125°C. Both are supplied in the same 28-pin TSSOP package (LP suffix) and are functionally identical in electrical parameters at 25°C.
Are the A3977SLPTR-T and A3977KLP-T pin-to-pin compatible?
Yes. Both devices use the same 28-pin TSSOP (LP) package with identical pin assignments. The only difference is the temperature grade and the associated part number suffix. They can be used interchangeably on the same PCB footprint, provided the application's operating temperature range is satisfied by the selected grade.
What is the maximum output current rating for these devices?
Both the A3977SLPTR-T and A3977KLP-T are rated for a maximum output current of ±2.5 A per bridge, with a peak output current of ±2.5 A and a continuous output current of ±2.0 A per bridge (subject to proper thermal management). These ratings are specified in the Allegro A3977 datasheet and are identical for both temperature grades.
What supply voltage range do the A3977SLPTR-T and A3977KLP-T support?
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 parameters are identical for both the S and K temperature grades.
Can the A3977SLPTR-T be used as a drop-in replacement for the A3977KLP-T in an automotive application?
No. The A3977SLPTR-T is only rated for -20°C to +85°C, while the A3977KLP-T is rated for -40°C to +125°C. Automotive applications typically require the wider temperature range and may require AEC-Q100 qualification, which the K-grade part is designed to meet. Substituting the S-grade part in an automotive environment could result in unreliable operation or failure outside its rated temperature range.
What microstepping resolutions are supported by the A3977SLPTR-T and A3977KLP-T?
Both devices support full-step, half-step, quarter-step, and eighth-step microstepping modes, selectable via the MS1 and MS2 logic inputs. The internal translator and PWM current control are identical between the two temperature grades.
Do the A3977SLPTR-T and A3977KLP-T have the same thermal characteristics?
No. While the package thermal resistance (RθJA) is the same for both devices in the same TSSOP-28 package, the maximum allowable junction temperature and the ambient temperature range differ. The A3977KLP-T supports a higher maximum ambient temperature (+125°C) and therefore requires more careful thermal design to keep the junction temperature within limits at elevated ambient conditions. The A3977SLPTR-T is limited to +85°C ambient.
Are the A3977SLPTR-T and A3977KLP-T RoHS compliant?
Yes. Both the A3977SLPTR-T and A3977KLP-T are RoHS-compliant and halogen-free, as stated in the Allegro MicroSystems product datasheet and material declaration documentation. The "-T" suffix in both part numbers indicates tape-and-reel packaging.