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Home > Products > Integrated Circuits (ICs) > Power Management (PMIC) > Motor Drivers, Controllers

Toshiba Semiconductor and Storage TC78S121FTG,EL

Name: TC78S121FTG,EL
Brand: Toshiba Semiconductor and Storage
SKU: TC78S121FTG,EL
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: TC78S121FTG,EL

Manufacturer:: Toshiba Semiconductor and Storage

Category:: Motor Drivers, Controllers

Package:: 48-VFQFN Exposed Pad

Datasheet:: TC78S121FTG,EL.pdf

Description:: IC MTR DRVR BIPLR 4.5-5.5V 48QFN

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Product details

Overview

TC78S121FTG from Toshiba is a PWM chopper-type dual-stepping motor driver IC with monolithic CD-process silicon construction, integrating two H-bridge pairs for driving up to two bipolar stepping motors or four brushed DC motors. It delivers 1.5 A max per phase in Stepping Motor (S) mode, supports 40 V max output withstand voltage, and features integrated VCC regulation eliminating need for external 5 V supply.

For engineers reviewing the TC78S121FTG datasheet, TC78S121FTG pinout, TC78S121FTG application, or TC78S121FTG equivalent, key selection considerations include its dual-channel mixed-decay current control, configurable chopping frequency (40–150 kHz), large/small mode ON-resistance options (0.3 Ω / 0.6 Ω), thermal shutdown (150°C typ.), and over-current detection (ISD) with digital/analog blanking.

Technical Context

The TC78S121FTG implements a mixed-decay PWM chopper architecture with automatic transition among Charge, Slow-Decay, and Fast-Decay modes based on real-time current feedback via RS pins. Its OSCM oscillator-tunable via external RC network-sets both chopping frequency and digital tBLANK timing, enabling precise torque control in stepping motor mode and robust short-brake/PWM operation in DC motor mode.

Motor drive mode is statically selected via MODE0/MODE1/MODE2 pins, supporting six functional configurations including Stepping Motor ×2, DC Motor ×4, and combination modes where H-bridges are paralleled to halve effective ON-resistance and double current capability. All logic inputs feature internal 100 kΩ pull-down resistors, and ALERT provides open-drain fault reporting for ISD/TSD events.

Key Specifications

Parameter	Value and Actual Design Meaning
Max Output Withstand Voltage	40 V - Enables direct interface with 24 V industrial motor rails without level-shifting or clamping.
Output Current (Stepping S-mode)	1.5 A (max) per phase - Supports NEMA 17–23 stepper motors at full-step or microstepping with adequate heatsinking.
ON-Resistance (Large Mode)	0.3 Ω (H+L) - Reduces conduction loss by ~50% vs Small Mode, critical for high-current parallel H-bridge operation.
Chopping Frequency Range	40–150 kHz - Adjustable via external RC on OSCM pin; higher frequencies suppress audible noise and improve current regulation fidelity.
VCC Regulator Output	5.0 V (typ.) - Powers internal logic and eliminates need for external 5 V rail, simplifying system BOM and layout.
TSD Activation Threshold	150°C (typ.) - Thermal shutdown protects against sustained overload; recovery requires VM power cycle or SLEEP toggle.
ISD Detection Threshold	4.0 A (typ.) - Over-current protection triggers within 4–8 × CR time; requires external fuse for fail-safe fault clearing.

Pinout & Package

Package: QFN48-P-0707-0.50 - 7 mm × 7 mm, 0.5 mm pitch, exposed thermal pad (EP) for enhanced heat dissipation; requires single-point GND connection and proper copper pour under EP.

Pin/Terminal	Circuit Role	Design Meaning
VM	Motor Power Supply Input	Primary high-side rail (8–38 V); must be decoupled near package with ≥10 μF low-ESR capacitor.
VCC	Internal Regulator Output	5 V supply for logic; powers MODE/PHASE/IN pins; no external source required.
OUT_A+/A−, OUT_B+/B−, OUT_C+/C−, OUT_D+/D−	H-Bridge Output Terminals	Four independent half-bridge pairs; configured as two full-stepper bridges or four DC motor drivers per mode table.
RS_A, RS_B, RS_C, RS_D	Current Sense Inputs	Connect to low-side sense resistors (e.g., 0.51 Ω); feed analog current feedback to internal comparators.
PHASE_A/B/C/D, IN_X1/X2	Stepper Control Inputs	Digital step/direction interface; PHASE sets polarity, IN_X1/X2 define full/half/microstep sequence per channel.
MODE0/1/2	Drive Mode Select	Static 3-bit configuration; determines H-bridge topology (S×2, L×1, DC×4, etc.); must be fixed before power-on.
SLEEP	Low-Power Control	Active-high; disables VCC regulator and halts all logic; wake-up latency ≤1 ms after rising edge.
ALERT	Open-Drain Fault Output	Pulled low on ISD/TSD event; requires external 10 kΩ pull-up to VCC for valid logic-level signaling.
VREF	Current Reference Input	Analog voltage (3.0–4.0 V) setting peak motor current via I_OUT = VREF / 5.0 / R_RS.
OSCM	Chopping Oscillator Terminal	RC network (e.g., 270 pF + 100 kΩ) sets OSCM frequency (1.2–2.0 MHz), directly scaling f_chop and tBLANK.

Key Features

Feature	Design Value
Integrated VCC Regulator	Eliminates need for external 5 V supply, reducing component count and PCB area in space-constrained designs.
Configurable Mixed-Decay Control	37.5 % or 12.5 % fixed decay ratio selectable per channel pair via D_TBLANK_AB/CD, optimizing torque ripple and efficiency.
Dual tBLANK Architecture	Analog tBLANK (550 ns typ.) for stepper IRR suppression; digital tBLANK (2.5 μs typ.) for DC motor varistor recovery, preventing false ISD trips.
Large/Small Mode Flexibility	Parallel H-bridge connection (Large Mode) cuts effective Ron to 0.3 Ω while doubling current capacity-enabling higher-power motor drives without redesign.
Comprehensive Protection Suite	Hardware-based ISD (4.0 A threshold), TSD (150°C), VM/VCC monitoring, and POR ensure robust operation under fault conditions.

Applications

Industrial CNC Positioning	Medical Infusion Pump Actuation
Use Scenario: Precise open-loop positioning of X/Y/Z axes in desktop CNC mills using NEMA 17 bipolar stepper motors. IC Role / Device Role / Timing Role: Dual-channel stepper driver executing full-step and half-step sequences with constant-current chopping at 100 kHz to minimize vibration and resonance. Use Value: Integrated VCC regulation and 0.6 Ω (S-mode) or 0.3 Ω (L-mode) ON-resistance reduce thermal load and enable compact heatsinkless designs at ≤1.5 A per phase.	Use Scenario: Controlled peristaltic motion in portable infusion pumps requiring silent, low-EMI motor operation across battery voltage range (10–24 V). IC Role / Device Role / Timing Role: Stepping Motor (S) ×2 controller managing two independent pump heads with microstepping resolution and adaptive decay timing. Use Value: Analog tBLANK (550 ns) suppresses diode recovery noise during high-frequency chopping, ensuring stable current regulation and quiet motor operation.
Automated Retail Kiosk Dispensers	Robotic Arm Joint Control
Use Scenario: Bidirectional actuation of solenoid-driven product dispensers and flap mechanisms in unattended retail kiosks. IC Role / Device Role / Timing Role: DC Motor (S) ×4 driver operating four 12 V brushed DC actuators with PWM speed control and short-brake functionality. Use Value: Digital tBLANK (2.5 μs) prevents false over-current detection during PWM transitions, enabling reliable high-speed actuator sequencing without software intervention.	Use Scenario: Torque-controlled joint movement in collaborative robotic arms using dual NEMA 23 stepper motors with dynamic load compensation. IC Role / Device Role / Timing Role: Stepping Motor (L) ×1 driver combining channels A/B and C/D into two high-current (≤2.1 A) full bridges with shared current sensing. Use Value: Large Mode reduces combined H-bridge ON-resistance to 0.3 Ω, lowering conduction losses by 50% and enabling higher holding torque at elevated ambient temperatures.

Industrial CNC Positioning

Medical Infusion Pump Actuation

Use Scenario: Precise open-loop positioning of X/Y/Z axes in desktop CNC mills using NEMA 17 bipolar stepper motors.

IC Role / Device Role / Timing Role: Dual-channel stepper driver executing full-step and half-step sequences with constant-current chopping at 100 kHz to minimize vibration and resonance.

Use Value: Integrated VCC regulation and 0.6 Ω (S-mode) or 0.3 Ω (L-mode) ON-resistance reduce thermal load and enable compact heatsinkless designs at ≤1.5 A per phase.

Use Scenario: Controlled peristaltic motion in portable infusion pumps requiring silent, low-EMI motor operation across battery voltage range (10–24 V).

IC Role / Device Role / Timing Role: Stepping Motor (S) ×2 controller managing two independent pump heads with microstepping resolution and adaptive decay timing.

Use Value: Analog tBLANK (550 ns) suppresses diode recovery noise during high-frequency chopping, ensuring stable current regulation and quiet motor operation.

Automated Retail Kiosk Dispensers

Robotic Arm Joint Control

Use Scenario: Bidirectional actuation of solenoid-driven product dispensers and flap mechanisms in unattended retail kiosks.

IC Role / Device Role / Timing Role: DC Motor (S) ×4 driver operating four 12 V brushed DC actuators with PWM speed control and short-brake functionality.

Use Value: Digital tBLANK (2.5 μs) prevents false over-current detection during PWM transitions, enabling reliable high-speed actuator sequencing without software intervention.

Use Scenario: Torque-controlled joint movement in collaborative robotic arms using dual NEMA 23 stepper motors with dynamic load compensation.

IC Role / Device Role / Timing Role: Stepping Motor (L) ×1 driver combining channels A/B and C/D into two high-current (≤2.1 A) full bridges with shared current sensing.

Use Value: Large Mode reduces combined H-bridge ON-resistance to 0.3 Ω, lowering conduction losses by 50% and enabling higher holding torque at elevated ambient temperatures.

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-H-bridge motor driver applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
TB6600HG	Higher voltage rating (50 V), but discrete external MOSFETs required; no integrated VCC regulator; larger footprint (HTSSOP-28).	Targeted at high-voltage (>36 V) stepper systems; lacks on-chip current regulation and mixed-decay control.	Choose TB6600HG only when >40 V motor supply or discrete FET optimization is mandatory; TC78S121FTG offers superior integration and thermal efficiency at ≤38 V.
DRV8825	Microstepping up to 1/32, but lower max current (2.2 A), no large-mode parallelization, and no digital tBLANK; requires external 3.3 V logic supply.	Focused on precision microstepping in low-noise lab equipment; lacks robust DC motor support and fault reporting.	Select DRV8825 for ultra-fine positioning where microstepping resolution outweighs fault resilience; TC78S121FTG better suits industrial environments demanding ISD/ALERT and dual-mode flexibility.

Compared with TB6600HG and DRV8825, the TC78S121FTG uniquely combines integrated VCC regulation, dual tBLANK architecture, and hardware-configurable Large/Small modes-enabling compact, thermally efficient designs for mixed stepper/DC motor systems without external support components.

Availability

TC78S121FTG is available at Aetrix Electronics and suitable for industrial CNC positioning, medical infusion pump actuation, automated retail kiosk dispensers, and robotic arm joint control requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.

Supply support for TC78S121FTG 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 motor driver ICs and power management.

The TC78S121FTG belongs to Toshiba's CD-process motor driver family, engineered specifically for compact, thermally efficient control of bipolar stepper and brushed DC motors in space- and power-constrained embedded systems.

FAQ

What motor types and configurations does the TC78S121FTG support?

The TC78S121FTG supports six static drive modes selected via MODE0–MODE2 pins: Stepping Motor (S) ×2, DC Motor (L) ×2, Stepping Motor (L) ×1, DC Motor (S) ×4, and two combination modes. It can drive up to two bipolar stepper motors or four brushed DC motors using its four H-bridge outputs. The TC78S121FTG does not support dynamic mode switching-configuration must be fixed before power-on.

How does the TC78S121FTG implement current regulation and decay control?

The TC78S121FTG uses PWM chopper-based constant-current control with real-time feedback from RS sense resistors. It automatically cycles through Charge, Slow-Decay, and Fast-Decay modes to maintain target current. Decay ratio is fixed at 37.5 % or 12.5 % per channel pair, selected via D_TBLANK_AB/CD pins. The TC78S121FTG calculates peak current as I_OUT = VREF / 5.0 / R_RS, where VREF is applied to the VREF pin.

What protection features are built into the TC78S121FTG?

The TC78S121FTG integrates over-current detection (ISD) with 4.0 A typical threshold, thermal shutdown (TSD) at 150°C junction temperature, VM and VCC power monitors, and power-on reset (POR). ISD and TSD trigger an output halt and assert the open-drain ALERT pin low. Recovery requires VM power cycle or SLEEP pin toggle. The TC78S121FTG also includes internal dead-band timing to prevent shoot-through and analog/digital tBLANK to suppress false ISD trips.

Can the TC78S121FTG operate without an external 5 V supply?

Yes-the TC78S121FTG incorporates an internal VCC regulator that generates a stable 5.0 V (typ.) supply from the VM rail for all internal logic and interface pins. This eliminates the need for an external 5 V source, simplifying system design and reducing BOM cost. The TC78S121FTG specifies VCC output current capability up to 5 mA, sufficient for driving its own logic and light external loads.

What is the significance of Large Mode versus Small Mode in the TC78S121FTG?

In Large Mode, the TC78S121FTG internally parallels H-bridge pairs (A/B and C/D), reducing effective ON-resistance to 0.3 Ω (vs 0.6 Ω in Small Mode) and doubling current capability-up to 2.1 A per phase in Stepping Motor (L) mode. This mode requires board-level shorting of corresponding VM, GND, and output pins, with strict impedance balancing to prevent current imbalance. The TC78S121FTG's datasheet explicitly warns that unbalanced routing in Large Mode may exceed absolute maximum ratings and cause permanent damage.

TC78S121FTG,EL Specifications

Product attributes: Attribute value

Manufacturer:: Toshiba Semiconductor and Storage

Series:: -

Package/Case:: 48-VFQFN Exposed Pad

Packaging:: Tape & Reel (TR)

Product Status:: Active

Motor Type - Stepper:: Bipolar

Motor Type - AC, DC:: Brushed DC

Function:: Driver - Fully Integrated, Control and Power Stage

Output Configuration:: Half Bridge (8)

Interface:: Parallel

Technology:: Power MOSFET

Step Resolution:: -

Applications:: General Purpose

Current - Output:: 2A

Voltage - Supply:: 4.5V ~ 5.5V

Voltage - Load:: 8V ~ 38V

Operating Temperature:: -20°C ~ 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 48-QFN (7x7)

TC78S121FTG,EL FAQ

1.How can I place an order for TC78S121FTG,EL through Aetrix?

Please submit a Request for Quotation (RFQ) for TC78S121FTG,EL on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for TC78S121FTG,EL reliable?

The price and inventory of TC78S121FTG,EL are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TC78S121FTG,EL is usually 5 days.

3.What payment methods are accepted for TC78S121FTG,EL?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TC78S121FTG,EL transactions.

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4.How is shipping managed for TC78S121FTG,EL?

TC78S121FTG,EL orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your TC78S121FTG,EL order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for TC78S121FTG,EL?

For technical support, including TC78S121FTG,EL datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TC78S121FTG,EL requirements.

6.How does Aetrix verify that TC78S121FTG,EL is sourced from the original manufacturer or authorized distributors?

All TC78S121FTG,EL products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that TC78S121FTG,EL meets industry standards.

7.What is the process for return or replacement of TC78S121FTG,EL?

All TC78S121FTG,EL units undergo pre-shipment inspection (PSI). If there is an issue with TC78S121FTG,EL, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The TC78S121FTG,EL part is unused and in its original packaging.

Return procedure for TC78S121FTG,EL:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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