STMicroelectronics L6228QTR

Overview

L6228QTR from STMicroelectronics is a DMOS dual full-bridge stepper motor driver IC for bipolar stepper motors, featuring non-dissipative overcurrent protection, dual independent constant t_OFF PWM current controllers, and fast/slow decay mode selection. It operates from 8–52 V supply, delivers 2.8 A peak (1.4 A_r.m.s.) output current per bridge, and supports up to 100 kHz switching frequency - used in precision motion control systems requiring microstepping-capable drive logic and thermal robustness.

For engineers reviewing the L6228QTR datasheet, L6228QTR pinout, L6228QTR application, or L6228QTR equivalent, this page provides verified technical context on its two-phase chopping regulation, VFQFPN32 package layout, half/full-step decoding logic, and design-critical parameters including R_DS(on) = 0.73 Ω (typ. @ 25 °C), t_DT = 1 µs dead time, and integrated charge pump (V_CP = 600 kHz).

Technical Context

The L6228QTR integrates two independent DMOS full-bridges with intrinsic fast freewheeling diodes and uses BCD multipower technology to co-integrate power transistors with CMOS/bipolar control circuitry. Its phase sequence generator implements full-step (two-phase-on/wave) and half-step modes via dedicated logic inputs (HALF/FULL, CW/CCW, CLOCK).

PWM current regulation employs dual constant-off-time controllers with blanking (t_BLANK = 1 µs) and RC-settable t_OFF (6.6 µs–6 ms), while decay behavior is selected by CONTROL pin: fast decay (both MOSFETs off) enables high dI/dt recirculation; slow decay (low-side off only) sustains current with low voltage drop across the coil.

Key Specifications

Pinout & Package

Package: VFQFPN32 (5 mm × 5 mm, 0.5 mm pitch), thermally enhanced with exposed die pad connected to GND (pins 1 & 21).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TB6600HG and DRV8825, the L6228QTR uniquely combines 52 V operation, integrated charge pump, and non-dissipative overcurrent protection in a compact VFQFPN32 package - making it optimal for industrial motion systems demanding robustness, simplicity, and thermal resilience without external support circuitry.

Availability

L6228QTR is available at Aetrix Electronics and suitable for industrial CNC positioning, medical infusion pumps, automated laboratory analyzers, and 3D printer extruder control requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.

Supply support for L6228QTR 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, MCU, power, and sensor solutions for industrial, automotive, and consumer markets.

The L6228QTR belongs to ST's Power Transistor & Motor Driver product line, engineered specifically for high-efficiency, thermally robust bipolar stepper motor control in space- and reliability-constrained embedded motion systems.

FAQ

What is the recommended external RC network for t_OFF = 25 µs per bridge?

For t_OFF ≈ 25 µs, use R_OFF = 47 kΩ and C_OFF = 1 nF per bridge (RCA/RCB to GND). This yields t_RCFALL = 0.6 × 47 kΩ × 1 nF = 28.2 µs, plus 1 µs dead time = 29.2 µs total - within datasheet tolerance. Ensure COFF has ≤100 pF parasitic capacitance and place RC networks close to respective RCA/RCB pins to minimize noise coupling.

How does the L6228QTR handle motor stall conditions?

During stall, winding current rises until V_SENSE exceeds V_REF, triggering PWM off-time. If current remains elevated beyond ISOVER = 2.8 A (T_J-dependent), the non-dissipative overcurrent protection activates within 200 ns, pulling EN low and disabling both bridges. Recovery requires RESET assertion or EN re-enable after fault clearance - no latch-up occurs.

Can the L6228QTR drive unipolar stepper motors?

No - the L6228QTR is designed exclusively for two-phase bipolar stepper motors with center-tapped windings unsupported. Its dual full-bridge topology requires four-wire (A+, A−, B+, B−) connection and cannot replicate the single-polarity drive needed for unipolar 5/6-wire motors. Use dedicated unipolar drivers like ULN2003A instead.

What is the minimum copper area required for thermal performance at 1.4 A_r.m.s. per bridge?

To maintain T_J < 125 °C at 1.4 A_r.m.s. per bridge with R_th(JA) = 42 °C/W, the PCB must provide ≥0.5 cm² top-side copper connected to the exposed die pad (pins 1/21) and ≥6 cm² ground layer linked via ≥18 thermal vias. Reduce ambient temperature or add airflow if operating above 70 °C ambient.