Toshiba Semiconductor and Storage TB67S521FTAG,EL

Overview

TB67S521FTAG from Toshiba is a BiCD-process, PWM chopper-type 2-phase bipolar stepping motor driver IC rated for 40 V motor supply and 2.8 A per channel (absolute max), featuring integrated VCC regulation, mixed-decay current control, and full/half/quarter-step resolution. It drives industrial automation actuators, precision optical positioning stages, and CNC motion modules with on-chip thermal shutdown (TSD), over-current detection (ISD), and power-on reset (POR).

For engineers reviewing the TB67S521FTAG datasheet, TB67S521FTAG pinout, TB67S521FTAG application, or TB67S521FTAG equivalent, key selection criteria include its 0.53 Ω typical H+L output ON-resistance, 40–150 kHz adjustable chopping frequency, ±1.0 V RS-pin voltage range, 140–170 °C TSD activation window, and P-WQFN36-0606-0.50-002 package thermal performance under 2.5 A continuous phase current.

Technical Context

The TB67S521FTAG implements a dual H-bridge output stage using DMOSFETs fabricated in Toshiba's BiCD process, enabling 40 V withstand voltage and 2.8 A absolute maximum output per phase. Its internal oscillator (OSCM) sets chopper frequency via external RC network (e.g., 270 pF + 3.6 kΩ → 1.6 MHz OSCM → 100 kHz fchop), while mixed-decay mode dynamically allocates 37.5% of each chopper cycle to slow decay and 62.5% to fast decay based on current threshold comparison.

Control logic accepts PHASE/IN inputs to determine current direction and step resolution (full/half/quarter), with independent VREF_A/VREF_B bias pins setting peak current per channel via external sense resistors (e.g., 0.51 Ω + 3.0 V → 1.18 A). The on-chip 5 V VCC regulator allows single VM supply operation, and all GND traces must be routed to a single-point earth to minimize noise and ensure thermal stability.

Key Specifications

Pinout & Package

Package: P-WQFN36-0606-0.50-002 - 6 mm × 6 mm, 0.5 mm pitch, exposed thermal pad, 0.14 g weight. Optimized for high-power density motor drive applications with low thermal resistance to PCB.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STSPIN820 and MP6500, the TB67S521FTAG provides superior current control flexibility via dual VREF pins and adaptive mixed-decay timing-enabling smoother low-speed operation and tighter torque consistency across varying load inertia, at the cost of larger footprint and external RC timing components.

Availability

TB67S521FTAG is available at Aetrix Electronics and suitable for industrial CNC positioning, medical imaging actuators, automated optical inspection systems, and lab automation pipetting platforms requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.

Supply support for TB67S521FTAG 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

Toshiba Electronic Devices & Storage Corporation designs high-reliability semiconductor solutions for automotive, industrial, and consumer applications, with leadership in power management and motor control ICs.

The TB67S521FTAG belongs to Toshiba's BiCD-based stepping motor driver family, engineered specifically for high-voltage, high-current industrial motion control where thermal robustness, precise current regulation, and integrated protection are non-negotiable.

FAQ

What is the maximum continuous output current supported by the TB67S521FTAG in real-world PCB layouts?

The TB67S521FTAG supports 2.5 A per channel continuously under Ta ≤ 85°C with appropriate PCB thermal design-specifically a 4-layer board (100 mm × 110 mm, 1.6 mm thick) with 55 μm Cu on outer layers. At 2.5 A, its 0.53 Ω typical H+L ON-resistance generates ~3.3 W total dissipation, requiring the exposed thermal pad to be soldered to a large copper pour. Exceeding 2.5 A risks repeated TSD activation unless ambient temperature is reduced or forced-air cooling is added. Always verify junction temperature using Tj = Ta + (PD × θJA) in your final layout.

How does the mixed-decay mode in the TB67S521FTAG improve motor performance compared to fixed-slow or fixed-fast decay?

The TB67S521FTAG's mixed-decay mode dynamically allocates 37.5% of each chopper cycle to slow decay and 62.5% to fast decay based on real-time current threshold comparison. This balances torque smoothness (slow decay maintains current during zero-crossing) and back-EMF suppression (fast decay rapidly recirculates energy), reducing low-speed vibration and mid-band resonance by up to 40% versus fixed-decay drivers. Unlike fixed modes, it adapts to load inertia changes without firmware intervention-making it ideal for variable-torque applications like robotic joint control or camera gimbal stabilization.

Can the TB67S521FTAG operate with only a single 24 V supply, or does it require separate VM and VCC rails?

Yes, the TB67S521FTAG can operate with only a single 24 V supply on the VM pin. Its integrated VCC regulator generates a stable 5 V internal bias from VM, powering all logic circuits-including PHASE/IN inputs, oscillator, and protection blocks-without needing an external 5 V rail. This simplifies power architecture and reduces component count. However, VCC must not be externally driven; doing so may damage the internal regulator. The VCC pin is for monitoring only and should remain unconnected to external supplies.

What are the critical PCB layout requirements for reliable operation of the TB67S521FTAG?

Reliable TB67S521FTAG operation demands strict PCB layout: (1) All GND pins (10×) must connect to a single-point earth plane beneath the IC to minimize ground bounce; (2) VM and output traces (OUT_A1+/A2+/B1+/B2+, OUT_A1−/A2−/B1−/B2−) require ≥1 mm width and short, direct paths to reduce inductance; (3) RS sense resistors must be placed adjacent to RS_A1/RS_A2 pins with Kelvin connections; (4) The exposed thermal pad must be fully soldered to a ≥200 mm² copper pour with ≥4 thermal vias (0.3 mm diameter) to inner ground planes. Failure to follow these causes ISD false triggers, TSD premature activation, or output shoot-through.

How do I calculate the required sense resistor value for a target peak current of 1.8 A per phase using the TB67S521FTAG?

To achieve 1.8 A peak current per phase with the TB67S521FTAG, use the formula I_OUT = VREF × (1/5.0) / R_S. With VREF = 3.0 V (typical max), solve for R_S: R_S = 3.0 V / 5.0 / 1.8 A = 0.333 Ω. Select a standard 0.33 Ω, 1% tolerance, 1 W metal-strip resistor. Verify actual current with oscilloscope measurement at RS pins: V_RS = I_OUT × R_S = 1.8 A × 0.33 Ω = 0.594 V. Ensure V_RS stays within ±1.0 V common-mode range. For tighter accuracy, calibrate VREF with multimeter and adjust R_S accordingly-e.g., if measured VREF = 2.95 V, use R_S = 2.95 / 5.0 / 1.8 = 0.328 Ω.