A3977SLPTR Equivalent & Substitute Parts

Part Overview

The A3977SLPTR is a bipolar stepper motor driver IC manufactured by Allegro MicroSystems, designed for fully integrated motor control and power stage applications. This device integrates DMOS logic technology with half-bridge output configuration, supporting step resolutions from full step to 1/8 microstepping. The A3977SLPTR operates across a supply voltage range of 3V to 5.5V with load voltage capability from 8V to 35V, delivering 2.5A output current per channel.

The A3977SLPTR is classified as obsolete. Identifying equivalent substitute parts is necessary to ensure design continuity, maintain supply chain reliability, and support ongoing production requirements for applications utilizing this motor driver architecture.

Substiute Parts

A3977SLPTR

Allegro MicroSystemsIn Stock: 42646A3977SLPTR Datasheet

Current PartRFQ

A3977SLPTR-T

Allegro MicroSystemsIn Stock: 11238A3977SLPTR-T Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the A3977SLPTR is determined by strict equivalence across the following electrical and mechanical parameters:

• Motor driver type and control architecture (bipolar stepper, fully integrated)
• Output configuration (half bridge with 4 channels)
• Electrical specifications (2.5A output current, 3V–5.5V supply, 8V–35V load voltage)
• Step resolution capability (1, 1/2, 1/4, 1/8)
• Package form factor (28-TSSOP with exposed pad)
• Operating temperature range (-20°C to 150°C)

The A3977SLPTR-T meets all these criteria and qualifies as a direct substitute. Both parts share identical electrical performance, functional integration, and physical packaging specifications. The primary distinction between these parts relates to product status and compliance certifications rather than technical performance parameters.

Parameter Comparison

Engineering Selection Recommendations

The A3977SLPTR-T is the direct substitute for the obsolete A3977SLPTR. Both parts deliver identical electrical performance and physical compatibility. Selection between these parts should be based on the following factors:

Product Status: The A3977SLPTR is obsolete and subject to availability constraints. The A3977SLPTR-T maintains active product status with established supply chain availability.

Compliance Requirements: The A3977SLPTR-T is ROHS3 compliant, whereas the A3977SLPTR is non-compliant. Applications subject to RoHS regulations or customer compliance mandates require the A3977SLPTR-T.

Moisture Sensitivity: The A3977SLPTR carries MSL 1 (unlimited shelf life), while the A3977SLPTR-T carries MSL 2 (1-year shelf life). Storage and handling protocols differ accordingly.

For new designs or production continuity, the A3977SLPTR-T is the appropriate selection. For legacy systems where the original part number must be maintained, the A3977SLPTR remains functionally equivalent where available inventory permits.

Frequently Asked Questions (FAQ)

Q: Can the A3977SLPTR-T replace the A3977SLPTR in existing designs?

A: Yes. The A3977SLPTR-T is electrically and mechanically equivalent. Both parts feature identical output current (2.5A), supply voltage range (3V–5.5V), load voltage range (8V–35V), step resolution capability (1, 1/2, 1/4, 1/8), and 28-TSSOP package form factor. No circuit modifications are required.

Q: What is the difference between these two part numbers?

A: The primary differences are product status, RoHS compliance, and moisture sensitivity level. The A3977SLPTR is obsolete and RoHS non-compliant with MSL 1. The A3977SLPTR-T is active, ROHS3 compliant, and carries MSL 2 (1-year shelf life).

Q: Are there any package or pinout differences?

A: No. Both parts use the 28-TSSOP package with exposed pad (0.173" width, 4.40mm). Pinout and PCB footprint are identical.

Q: Which part should I specify for new production?

A: Specify the A3977SLPTR-T for new designs and ongoing production. It maintains active status, ensures regulatory compliance, and provides supply chain continuity.

Q: Does the MSL 2 rating of the A3977SLPTR-T affect usability?

A: MSL 2 requires storage at controlled humidity (≤60% RH) with a 1-year shelf life from the date of manufacture. Standard component handling and storage practices accommodate this requirement. The A3977SLPTR-T remains suitable for standard manufacturing environments.