Pololu MAX14870 Single Brushed DC Motor Driver CarrierPololu
The MAX14870 from Maxim Integrated is a tiny H-bridge motor driver IC that can be used for bidirectional control of one brushed DC motor at 4.5 V to 36 V. It can supply up to about 1.7 A continuously and can tolerate peak currents up to 2.5 A for a few seconds, making it a good choice for small motors that run on a wide range of voltages. The MAX14870 is a great IC, but its small surface-mount package makes it difficult for the typical student or hobbyist to use; our breakout board makes it easy to use with standard solderless breadboards and 0.1″ perfboards. Since this board is a carrier for the MAX14870, we recommend careful reading of the MAX14870 datasheet (492k pdf). The board ships populated with SMD components, including the MAX14870 and a reverse battery protection circuit.
- Single-channel H-bridge motor driver with shoot-through protection and internal free-wheeling diodes (can drive one DC motor)
- Motor supply voltage: 4.5 V to 36 V
- Output current: up to 1.7 A continuous (2.5 A peak)
- No separate logic supply needed; inputs are 3V- and 5V-compatible
- simple two-pin DIR/PWM interface (one pin controls direction and another controls speed)
- Under-voltage lockout on the logic supply and protection against over-current/short-circuit and over-temperature
- Carrier board adds reverse-voltage protection
- Active-low fault output indicates over-current or over-temperature condition
- Surface-mount resistor can optionally be added to enable automatic current limiting
- Compact size (0.6″×0.5″)
Two 1×5-pin breakaway 0.1″ male headers are included with the MAX14870 motor driver carrier, which can be soldered in to use the driver with breadboards,perfboards, or 0.1″ female connectors. (The headers might ship as a single 1×10 piece that can be broken in half.) The right picture above shows the two possible board orientations when used with these header pins (parts visible or silkscreen visible). You can also solder your motor leads and other connections directly to the board.
Using the motor driver
|Minimal wiring diagram for connecting a microcontroller to a MAX14870 Single Brushed DC Motor Driver Carrier.|
Motor and power connections are made on one side of the board and control connections are made on the other. The driver requires an operating voltage between 4.5 V and 36 V to be supplied to the reverse-protected power input, VIN. The VM pin provides convenient access to the reverse-protected supply voltage.
The MAX14870 offers a simple two-pin DIR/PWM control interface, where the DIR pin determines the motor direction and the PWM pin can be supplied with a PWM signal to control the motor speed. The PWM control input is pulled low on the carrier board through a 100 kΩ pull-down resistor. When the PWM pin is low, the motor outputs are both shorted to ground, which results in dynamic braking of a connected motor.
The EN pin can be driven high to turn off motor outputs, which is useful if you want to let the motor coast. The EN pin is pulled low through a 100 kΩ pull-up resistor on the carrier board so that the driver is enabled by default.
The following simplified truth table shows how the driver operates:
|1||X||X||high-impedance||high-impedance||coast (outputs floating/disconnected)|
|0||0||X||GND||GND||brake low (outputs shorted to ground)