STMicroelectronics TEA3718SFPTR

Overview

TEA3718SFPTR from STMicroelectronics is a bipolar stepper motor driver IC designed to regulate constant current in one winding of a bipolar stepper motor using switch-mode chopper control. It supports full-step and half-step modes, delivers up to 1.5 A output current, operates from 10–45 V motor supply (VS), features pre-alarm output for thermal monitoring, and integrates built-in protection diodes and H-bridge output stage - used in precision motion control for industrial automation actuators.

For engineers reviewing the TEA3718SFPTR datasheet, TEA3718SFPTR pinout, TEA3718SFPTR application, or TEA3718SFPTR equivalent, key selection criteria include its SO20 package thermal performance (R_th(j-a) = 60 °C/W), pre-alarm functionality at ~170 °C junction temperature, three-level logic-selectable current (via IN0/IN1), analog current adjust via REFERENCE pin, and compatibility with LS-TTL or microprocessor-controlled step/direction interfaces.

Technical Context

The TEA3718SFPTR implements a monostable-based chopper controller with three selectable comparator thresholds (V_CH/V_CM/V_CL = 390/230/65 mV) to set current levels, triggered by voltage across an external sense resistor. Its PHASE input controls current direction through an integrated Schmitt-triggered logic path with delay to prevent shoot-through during switching.

The output stage is a fully integrated H-bridge with four Darlington transistors and built-in flyback diodes; it uses pulse-time modulation (t_off = 0.69·R_TC_T) to regulate average winding current. The PRE-ALARM output asserts low at T_j ≈ 170 °C, enabling early thermal intervention without disabling drive - distinct from the ALARM-only variants like TEA3718SP.

Key Specifications

Pinout & Package

TEA3718SFPTR is housed in a 20-pin SOIC (Small Outline Integrated Circuit) package with gull-wing leads, ECOPACK®-compliant, rated for 0–70 °C ambient operation. Thermal performance assumes soldering on 4 cm² of 35 µm copper.

Key Features

Applications

Equivalent & Alternatives

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

Compared with L6219DS and TB6600HG, TEA3718SFPTR offers unique pre-alarm signaling in a compact SO20 package with integrated diodes - ideal for space-constrained industrial motion where early thermal awareness improves system uptime without increasing component count.

Availability

TEA3718SFPTR is available at Aetrix Electronics and suitable for industrial CNC positioning, automated laboratory equipment, PCB routing systems, and textile machine yarn feed control requiring stable component supply and long-term obsolescence management.

Supply support for TEA3718SFPTR 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing analog, digital, and mixed-signal ICs for industrial, automotive, and consumer applications.

The TEA3718 belongs to ST's legacy motor driver product line, engineered specifically for cost-effective, robust bipolar stepper control in industrial motion systems where reliability, thermal resilience, and minimal external components are critical.

FAQ

What is the function of the PULSE TIME pin?

The PULSE TIME pin accepts an RC network that sets the off-time (t_off) of the chopper circuit using the formula t_off = 0.69·R_TC_T. This timing directly controls current decay duration in the motor winding during regulation cycles, influencing torque smoothness and thermal behavior - typical values use 56 kΩ and 820 pF for ~30 ms off-time.

Can TEA3718SFPTR drive a unipolar stepper motor?

No - TEA3718SFPTR is designed exclusively for bipolar stepper motors with center-tapped windings. Its H-bridge architecture requires two-terminal winding connections (OUTA and OUTB) and cannot interface with unipolar configurations that rely on single-ended transistor switching and center-tap grounding.

How does the PRE-ALARM output differ from ALARM in other TEA3718 variants?

TEA3718SFPTR asserts PRE-ALARM low at ~170 °C junction temperature as an early warning, while ALARM variants (e.g., TEA3718SP) trigger only at higher temperature (~185 °C) and force immediate current reduction or shutdown. PRE-ALARM allows host systems to initiate controlled response - such as reducing step rate - before thermal fault occurs.

Is external current sense resistor required, and what value is typical?

Yes - an external low-inductance sense resistor (RS) is mandatory between SENSE RESISTOR pin and GND. For 1.2 A target current with V_CH = 390 mV threshold, RS = 0.325 Ω is typical; standard 0.33 Ω, 1% tolerance, 1 W metal-film resistors are commonly used and placed close to the IC for noise immunity.