STMicroelectronics L6208N

Overview

L6208N from STMicroelectronics is a DMOS dual full-bridge stepper motor driver IC designed for bipolar stepper motor control in industrial motion systems. It delivers 5.6 A peak output current (2.8 A RMS), operates from 8–52 V supply, features non-dissipative overcurrent protection, dual independent constant t_OFF PWM current controllers, and integrated fast freewheeling diodes.

For engineers reviewing the L6208N datasheet, L6208N pinout, L6208N application, or L6208N equivalent, this device is selected for precision open-loop stepper positioning where high-current drive, thermal robustness, decay mode flexibility (fast/slow), and on-chip current regulation are required - especially in CNC stages, automated valves, and lab instrumentation.

Technical Context

The L6208N integrates two independent DMOS full bridges with R_DS(ON) = 0.34 Ω (high-side, T_j = 25 °C) and built-in charge pump (V_CP = 600 kHz square wave) to drive N-channel high-side MOSFETs. Its phase sequence generator supports full-step (two-phase-on, one-phase-on) and half-step modes via dedicated logic inputs.

Current regulation uses dual independent PWM controllers with blanking time (t_BLANK = 1 µs) to suppress diode reverse-recovery spikes, and external RC networks (RCA/RCB) set t_OFF between 13 µs and 61 µs. Cross-conduction protection enforces 1 µs deadtime (t_DT) per bridge leg.

Key Specifications

Pinout & Package

Available in PowerDIP24 (20 + 2 + 2) package with exposed slug thermally connected to pins 1, 18, 19 (GND). The package provides R_th-j-amb = 43 °C/W (multilayer FR4, 6 cm² copper pour), supporting up to ~2.8 A continuous output with passive cooling.

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 L6208N uniquely combines non-dissipative overcurrent protection, integrated freewheeling diodes, and on-chip stepping logic in a single 24-pin DIP package - making it optimal for cost-sensitive, thermally constrained industrial designs requiring robust open-loop motion control without auxiliary support circuitry.

Availability

L6208N is available at Aetrix Electronics and suitable for industrial CNC positioning, automated laboratory valves, 3D printer extruder feed, and embedded motion control modules requiring stable component supply across long-lifecycle production programs.

Supply support for L6208N 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 specializing in power management, motion control, and industrial-grade analog/mixed-signal ICs.

The L6208N belongs to ST's "Stepper Motor Drivers" product line, engineered for ruggedized open-loop motion control in factory automation, test equipment, and precision electromechanical systems.

FAQ

What is the maximum allowable motor supply voltage for L6208N?

The absolute maximum supply voltage is 60 V, but the recommended operating range is 8–52 V per the datasheet. Operation above 52 V risks exceeding safe operating area limits of internal DMOS transistors and may trigger undervoltage lockout or thermal shutdown prematurely. For 48 V systems, derating is not required; for 52 V, ensure ambient temperature remains below 70 °C and heatsinking is adequate.

How does the non-dissipative overcurrent protection work without external sensing resistors?

The L6208N monitors high-side DMOS channel voltage drop during conduction. When V_DS exceeds a threshold corresponding to ~5.6 A peak current (at T_j = 25 °C), the internal comparator triggers immediate turn-off of the affected high-side switch. This method avoids power loss in external sense resistors while maintaining response time under 200 ns, as confirmed in Figure 7 of the datasheet.

Can L6208N drive unipolar stepper motors?

No - the L6208N is specifically designed for two-phase bipolar stepper motors with center-tapped windings excluded. Its dual full-bridge topology requires four-wire (A+, A−, B+, B−) connection and cannot replicate the unipolar switching pattern (e.g., transistor + center tap). Attempting unipolar use would result in incorrect phase energization and potential device damage due to improper current paths.

What thermal management is required for continuous 2.8 A RMS operation in PowerDIP24?

At 2.8 A RMS and 48 V supply, power dissipation is ~2.3 W per bridge (based on R_DS(ON) and duty cycle). With PowerDIP24's R_th-j-amb = 43 °C/W on 6 cm² copper, junction temperature rise is ~200 °C - exceeding 125 °C limit. Therefore, a minimum 25 cm² copper pour with thermal vias to inner ground planes or an external heatsink attached to the slug is mandatory to maintain T_j ≤ 125 °C.