Features and Specifications

• Dual-H-bridge motor driver: can drive two DC motors or one stepper motor
• Operating voltage: 2.710.8 V
• Output current: 1.2 A continuous (2 A peak) per motor
• Motor outputs can be paralleled to deliver 2.4 A continuous (4 A peak) to a single motor
• 3V-compatible inputs
• Undervoltage, overcurrent, and thermal shutdown
• Reverse-voltage protection circuit
• Current limiting can be enabled by adding sense resistors (not included)

Using the Motor Driver

In a typical application, power connections are made on one side of the board and control connections are made on the other. The nSLEEP pin is pulled high on the board and can be left disconnected if you do not want to use the low-power sleep mode of the DRV8833. Each of the two motor channels has a pair of control inputs, xIN1 and xIN2, that set the state of the corresponding outputs, xOUT1 and xOUT2; pulse width modulated (PWM) signal can be applied to each of these inputs. The control inputs are pulled low internally, effectively disabling the motor driver outputs by default. See the truth tables in the DRV8833 datasheet for more information on how the inputs affect the driver outputs.

The nFAULT pin is an open-drain output that is driven low by the chip whenever an over-current, over-temperature-or under-voltage condition occurs. Otherwise, it remains in a floating state, so you will need to connect an external pull-up resistor (or use a microcontroller input with its built-in pull-up enabled) if you want to monitor fault conditions on the driver.

Current Limiting

The DRV8833 can actively limit the current through the motors by using a fixed-frequency PWM current regulation (current chopping). By default, this carrier board connects the current sense pins to ground, disabling the current limiting feature. To enable current limiting, you can use a knife to cut the break points on the back of the board and then solder some appropriate current sense resistors to the unpopulated pads on the front, as indicated in the image below. The pads are sized for 1206 surface-mount resistors. Refer to the DRV8833 datasheet for information on how the resistor value determines the chopping current.

Real-World Power Dissipation Considerations

The DRV8833 datasheet recommends a maximum continuous current of 1.5 A per motor channel. However, the chip by itself will overheat at lower currents. For example, in our tests at room temperature with no forced air flow, the chip was able to deliver 1.5 A per channel for about a minute before the chip's thermal protection kicked in and disabled the motor outputs, while a continuous current of 1.2? - 1.3 A per channel was sustainable for many minutes without triggering a thermal shutdown. The actual current you can deliver will depend on how well you can keep the motor driver cool. The carrier's printed circuit board is designed to draw heat out of the motor driver chip, but performance can be improved by adding a heat sink. Our tests were conducted at 100% duty cycle; PWMing the motor will introduce additional heating proportional to the frequency.

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.

Included

• Two 1x8-pin breakaway 0.1" male headers
• 0.1" female connectors (The headers might ship as a single 1x16 piece that can be broken in half.)