Allegro MicroSystems A3980KLP

Overview

A3980KLP from Allegro MicroSystems is an automotive-grade DMOS bipolar stepper motor driver IC with integrated translator, designed for full-, half-, eighth-, and sixteenth-step microstepping at up to ±1 A output current and 35 V supply voltage. It features fixed off-time PWM current regulation, mixed/fast/slow decay mode selection, synchronous rectification, and dual fault flag diagnostics. It is used in automotive HVAC actuators, throttle control, and precision industrial positioning systems.

For engineers reviewing the A3980KLP datasheet, A3980KLP pinout, A3980KLP application, or A3980KLP equivalent, this page delivers verified technical context, validated pin functions, confirmed microstepping resolution modes (1/16-step), real thermal shutdown behavior (170°C typical), and two documented alternative parts aligned to Allegro's official transition guidance.

Technical Context

The A3980KLP implements a dual full-bridge DMOS output stage with internal charge pump (VCP) enabling high-side N-channel FET drive above VBB, and an internal VREG regulator powering sink-side drivers. Its translator logic accepts STEP/DIR/MS1/MS2 inputs and autonomously sequences DAC outputs to generate precise sinusoidal current waveforms across two motor phases.

Current regulation uses fixed off-time PWM with external RT/CT timing components (tOFF ≈ RT × CT), blanking time (tBLANK ≈ 1400 × CT), and automatic decay mode selection based on PFD voltage level and DAC step direction. Fault detection includes short-to-VBB, short-to-ground, open-load, and low-current diagnostics reported via FF1/FF2 open-drain flags.

Key Specifications

Pinout & Package

The A3980KLP is supplied in a 28-pin TSSOP package with exposed thermal pad (suffix LP), 1.1 mm profile, lead-free with 100% matte tin plating. Thermal resistance is 32°C/W (2-layer PCB) or 28°C/W (4-layer JEDEC).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar bipolar stepper motor driver applications.

Compared with A3980KLP, the A3981 offers superior thermal robustness and extended voltage tolerance for next-generation automotive platforms, while the TB6600HG provides basic drive functionality without translator or diagnostics - making it suitable only for legacy MCU-controlled systems where cost outweighs integration benefits.

Availability

A3980KLP is available at Aetrix Electronics and suitable for automotive HVAC actuation, industrial valve positioning, and medical infusion pump designs requiring stable component supply and long-term obsolescence management.

Supply support for A3980KLP includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Allegro MicroSystems is a U.S.-based designer of high-performance magnetic sensing and power ICs, specializing in motion control, energy-efficient power conversion, and automotive-grade reliability.

The A3980 product line was developed specifically for automotive and industrial stepper motor applications requiring integrated translation, robust fault handling, and AEC-Q100 qualification - targeting systems where MCU resources are constrained or safety-critical diagnostics are mandatory.

FAQ

What is the recommended microstepping resolution for optimal torque linearity in A3980KLP?

The A3980KLP achieves best torque linearity in 1/8-step mode, where phase current steps align closely with ideal sinusoidal distribution per Table 3. In 1/16-step mode, quantization error increases slightly but remains within ±5% of theoretical values. Full- and half-step modes deliver maximum torque per step but with higher vibration. For A3980KLP, use MS1=H/MS2=H for 1/16-step, and verify VREF ≤ 4 V to avoid exceeding SENSE pin limits.

Does A3980KLP support 24 V automotive battery systems with load dump transients?

Yes - A3980KLP includes overvoltage lockout (OVLO) triggered at 34 V typical, with 50 V absolute maximum rating for 500 ms. During load dump, it enters safety mode: all low-side FETs turn on and high-sides disable, allowing safe clamping. This behavior is explicitly validated in Allegro's A3980 datasheet Section "Supply Monitors" and applies directly to A3980KLP.

How does the A3980KLP handle open-load detection during motor startup?

A3980KLP detects open-load conditions by measuring phase current during the Home microstep position (45°, both phases at +70% I_TRIPMAX). If either phase current falls below 35% of I_TRIPMAX, FF1/FF2 report "Short to Ground" (L/H code) on the next STEP rising edge. The translator resets to Home at power-up or wake-from-sleep, enabling immediate open-load verification before motion begins.

Can A3980KLP operate with a 3.3 V microcontroller without level shifters?

Yes - A3980KLP accepts VDD from 3.0 V to 5.5 V and defines logic thresholds as percentages of VDD (VIH = 0.7×VDD, VIL = 0.3×VDD). At VDD = 3.3 V, VIH = 2.31 V and VIL = 0.99 V, fully compatible with standard 3.3 V CMOS outputs. No level shifting is needed for STEP, DIR, MS1, MS2, ENABLE, SLEEP, or PFD inputs.

What is the purpose of the SR (Synchronous Rectification) pin on A3980KLP?

The SR pin selects synchronous rectification mode: logic low enables active mode (FETs replace body diodes during decay, reducing power loss); logic high disables it (body diodes conduct, useful when external Schottky diodes handle heat). For A3980KLP, SR = low is recommended unless external diodes are thermally necessary - synchronous rectification cuts power dissipation by up to 35% in PWM operation.