TB67S128FTG Stepper Motor Driver Carrier

Pololu item #: 2998 0 in stock
Brand: Pololu
Status: Active and Preferred 
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1 13.95

Coming soon! A release date for this product has not been set yet, and this page is preliminary. More information, including a schematic and usage instructions, are coming soon.

This breakout board makes it easy to use Toshiba’s TB67S128FTG microstepping bipolar stepper motor driver, which features adjustable current limiting and microstepping down to 1/128-step. In addition, it dynamically selects an optimal decay mode by monitoring the actual motor current, and it can automatically reduce the driving current below the full amount when the motor is lightly loaded to minimize power and heat. The TB67S128FTG has a wide operating voltage range of 6.5 V to 44 V and can deliver approximately 2.1 A per phase continuously without a heat sink or forced air flow (up to 5 A peak). It features built-in protection against under-voltage, over-current, and over-temperature conditions; our carrier board also adds reverse-voltage protection (up to 40 V).

 Description Specs (15) Pictures (9) Resources (10) FAQs (4) On the blog (0) 


TB67S128FTG Stepper Motor Driver Carrier, bottom view with dimensions.

This product is a carrier board or breakout board for Toshiba’s TB67S128FTG stepper motor driver; we therefore recommend careful reading of the TB67S128FTG datasheet (2MB pdf) before using this product. This stepper motor driver offers microstep resolutions down to 1/128 of a step, and it lets you control one bipolar stepper motor at up to approximately 2.1 A per phase continuously (5 A peak) without a heat sink or forced air flow (see the Power Dissipation Considerations section below for more information.) The board breaks out every control pin and output of the TB67S128FTG , making all of the driver’s features available to the user.

Here are some of the board’s key features:
  • Two interface modes to select from:
    • clock mode for simple step and direction control
    • serial mode for controlling the driver’s many features through a serial interface (this mode also allows for serial control of the current limit)
  • Eight different step modes: full-step, half-step, 1/4-step, 1/8-step, 1/16-step, 1/32-step, 1/64-step, and 1/128-step
  • Adjustable current control lets you set the maximum current output with a potentiometer, which lets you use voltages above your stepper motor’s rated voltage to achieve higher step rates
  • Advanced Dynamic Mixed Decay (ADMD) dynamically switches between slow and fast decay modes by monitoring the state of current decay (not according to fixed timing)
  • Configurable Active Gain Control (AGC) automatically reduces drive current to minimize power consumption and heat generation when maximum torque is not needed
  • Motor supply voltage: 6.5 V to 44 V
  • Can deliver up to approximately 2.1 A per phase continuously (5 A peak) without additional cooling
  • Can interface directly with 3.3 V and 5 V systems
  • Protection against over-current/short-circuit and over-temperature
  • Open-load detection
  • Active-low error outputs indicate over-current, over-temperature, or open-load condition
  • Carrier board adds reverse-voltage protection up to 40 V
  • Carrier board breaks out all of the TB67S128FTG pins in a compact size (1.2″ × 1.6″)
  • Exposed solderable ground pad below the driver IC on the bottom of the PCB

Included hardware

This product ships with all surface-mount components installed as shown in the product picture. However, soldering is required for assembly of the included through-hole parts. The following through-hole parts are included:

The 0.1″ male headers can be broken or cut into smaller pieces as desired and soldered into the smaller through-holes. These headers are compatible with solderless breadboards, 0.1″ female connectors, and our premium and pre-crimped jumper wires. The terminal blocks can be soldered into the larger holes to allow for convenient temporary connections of unterminated power and motor wires (see our short video on terminal block installation). You can also solder your motor leads and other connections directly to the board for the most compact installation.

Using the driver

Minimal wiring diagram for connecting a microcontroller to a TB67S128FTG stepper motor driver carrier.


PIN Default Value Description
VIN 10 V to 47 V board power supply connection (reverse-protected up to 40 V).
GND Ground connection points for the motor power supply and control ground reference. The control source and the motor driver must share a common ground.
VM This pin gives access to the motor power supply after the reverse-voltage protection MOSFET (see the board schematic below). It can be used to supply reverse-protected power to other components in the system. It is generally intended as an output, but it can also be used to supply board power.
A+ Motor A output: “positive” end of phase A coil.
A− Motor output: “negative” end of phase A coil.
B+ Motor output: “positive” end of phase B coil.
B− Motor output: “negative” end of phase B coil.
VCC Regulated 5 V output: this pin gives access to the voltage from the internal regulator of the TB67S128FTG. The regulator can only provide a few milliamps, so the VCC output should only be used for logic inputs on the board (such as the neighboring IOREF pin), not for powering external devices.
IOREF All of the board signal outputs are open-drain outputs that are pulled up to IOREF, so this pin should be supplied with the logic voltage of the controlling system (e.g. 3.3 V for use in 3.3 V systems). For convenience, it can be connected to the neighboring V5 (OUT) pin when it is being used in a 5 V system.
VREF Voltage reference pins for setting the current limit.
LOW Step resolution selection pins.
CW/CCW (DIR) LOW Input that determines the direction of rotation.
CLK (STEP) LOW A rising edge on this input causes the driver to advance the motor by one step or microstep (moving the coil currents one step up or down in the translator table).
STANDBY LOW Standby mode input. By default, the driver pulls this pin low, disabling the motor outputs and internal oscillating circuit; it must be driven high to enable the driver.
ENABLE LOW Enable input. By default, the driver pulls this pin low, disabling the motor outputs; it must be driven high to enable the driver.
RESET LOW Reset input: driving this pin high resets the driver’s internal electrical angle (the state in the translator table that it is outputting).
MO This open-drain output is low when the driver’s internal electrical angle is at its initial value (the value after reset); otherwise, the board pulls it up to VCC.
HIGH Error outputs: these pins drive low to indicate that an error condition has occurred; otherwise, the board pulls them up to VCC. The specific error can be determined by the state of both error pins.
IF_SEL LOW Interface select pin. By default, the driver pulls this pin low, setting the driver in CLK mode, where the CLK input steps the electrical angle of the stepper motor. When driven high, the driver is in serial input mode, where settings can be configured and the motor can be controlled through a serial interface.
RS_SEL LOW RS mode select pin. By default, the driver pulls this pin low, enabling ACDS. When driven high, external current sense resistors can be added to the RS_x pins to set the current limiting.
EDG_SEL LOW CLK edge setting pin. By default, the driver pulls this pin low, where an up-edge of the CLK signal shifts the electrical angle per step. When driven high, both the up-edge and down-edge of the CLK signal shifts the electrical angle per step.
GAIN_SEL LOW Vref gain setting pin.
AGC HIGH These inputs determine whether Active Gain Control (AGC) is enabled. AGC0 should not be changed while the driver is operating. See the datasheet and the Active Gain Control section below for details about the AGC feature.
100 kΩ
These inputs set the bottom (minimum) current limit when AGC is active. CLIM1 is a four-state input.
FLIM 100 kΩ
This four-state input sets the bottom frequency limit (minimum step rate) for AGC to be active.
BOOST 100 kΩ
This four-state input determines how quickly the motor current is boosted back to the normal limit after the driver detects increased load torque with AGC active.
LTH 100 kΩ
This input controls the AGC detection threshold (torque detection sensitivity).
LOW Mixed Decay setting pins.
LOW Torque setting pins.
Current sense resistor connection pins. Optional external current-sensing resistors can be added to these pins.

Power dissipation considerations

The driver ICs have maximum current ratings higher than the continuous currents we specify for these carrier boards, but the actual current you can deliver depends on how well you can keep the IC cool. The carrier’s printed circuit board is designed to draw heat out of the IC, but to supply more than the specified continuous current per coil, a heat sink or other cooling method is required.

This product can get hot enough to burn you long before the chip overheats. Take care when handling this product and other components connected to it.

Please note that measuring the current draw at the power supply will generally not provide an accurate measure of the coil current. Since the input voltage to the driver can be significantly higher than the coil voltage, the measured current on the power supply can be quite a bit lower than the coil current (the driver and coil basically act like a switching step-down power supply). Also, if the supply voltage is very high compared to what the motor needs to achieve the set current, the duty cycle will be very low, which also leads to significant differences between average and RMS currents. Additionally, please note that the coil current is a function of the set current limit, but it does not necessarily equal the current limit setting as the actual current through each coil changes with each microstep and can be further reduced if Active Gain Control is active.

Schematic diagram

Schematic diagram of the TB67S128FTG Stepper Motor Driver Carrier.

This diagram is also available as a downloadable pdf: TB67S128FTG stepper motor driver carrier schematic (183k pdf)

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