In a typical application, the motor power supply is connected at the bottom of the board, the motor on the right side of the board, and the control connections to the left side of the board. The diagnostic/enable pins are pulled high on the board and can be left disconnected if you do not want to monitor the fault conditions of the motor driver chip. INA and INB control the direction of the motor, and the PWM pin turns the motor outputs on or off, allowing you to control motor speed with a supplied pulse width modulation (PWM) signal. The PWM pin is pulled low on the board, so the motor driver outputs are effectively disabled by default; the INA and INB pins are floating (they are not pulled to any particular default voltage). See the truth tables in the VNH2SP30/VNH3SP30 datasheet for more information on how the INA, INB, and PWM pins affect the driver outputs, OUTA and OUTB.

For the VNH2SP30 version, the current sense (CS) pin will output approximately 0.13 volts per amp of output current. If you want to add current sensing to the VNH3SP30 version, or if you want higher-accuracy current sensing with the VNH2SP30 version, please consider our ±30A ACS714 current sensor carrier.

Note: An 8-pin 0.1″ male header and two 2-pin terminal blocks are included but not soldered onto the boards. You can solder these in yourself and use this board with custom cables or solderless breadboards, or you can solder wires directly to the board for more compact installations.

The current-related values in the table below (i.e. the entries to which footnote 3 applies) are the results of tests on only one or two of each driver version, so they do not capture potential unit-to-unit variation. As such, the values should be treated as rough estimates of performance, not as performance guarantees. While these tests seem to indicate that the VNH2SP30 runs a bit cooler—and hence can deliver more continuous current—than the VNH5019, it is important to note that the three driver versions were tested at different times under potentially different conditions, so the results are not necessarily accurate indications of relative performance.

In our tests, we noticed that the thermal protection on the VNH5019 was activating at a lower temperature (153°C) than on the VNH2SP30 (170°C), which could partially account for the shorter VNH5019 overheating times. However, we also observed that the VNH5019 was reaching slightly higher temperatures than the VNH2SP30 when used under the same conditions: the VNH5019 reached a temperature of 85°C after 3 minutes at 10 A while the VNH2SP30 reached a temperature of 80°C.

The following table offers a comparison of the three drivers:

¹ The VNH3SP30 can survive input voltages up to 40 V, and the VNH2SP30 and VNH5019 can survive input voltages up to 41 V, but the over-voltage shutoff will kick in at lower voltages.
² While VNH3SP30’s over-voltage shutoff doesn’t activate until 36 V, in our experience, shoot-through currents make PWM operation impractical above 16 V.
³ Typical results using the Pololu motor driver carrier boards with 100% duty cycle at room temperature (with no forced airflow or heat sinking beyond the carrier PCB).

Real-world power dissipation considerations

The motor drivers have maximum current ratings of 30 A continuous. However, the chips by themselves will overheat at lower currents (see table above for typical values). The actual current you can deliver will depend on how well you can keep the motor driver cool. The carrier printed circuit board is designed to draw heat out of the motor driver chips, but performance can be improved by adding a heat sink. In our tests, we were able to deliver short durations (on the order of milliseconds) of 30 A and several seconds of 20 A without overheating. At 6 A, the chip gets just barely noticeably warm to the touch. For high-current installations, the motor and power supply wires should also be soldered directly instead of going through the supplied terminal blocks, which are rated for up to 15 A.

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.

Many motor controllers or speed controllers can have peak current ratings that are substantially higher than the continuous current rating; this is not the case with these motor drivers, which have a 30 A continuous rating and over-current protection that can kick in as low as 30 A (45 A typical). Therefore, the stall current of your motor should not be more than 30 A. (Even if you expect to run at a much lower average current, the motor can still draw short bursts of high currents, such as when it is starting, if special steps are not taken.)

Reverse-battery protection

The motor driver boards include an N-channel MOSFET for reverse-battery protection. This component keeps the motor driver from destroying itself if the input power is accidentally connected backwards. However, this component does slightly increase the total resistance between your battery and your motor. For slightly improved performance, the MOSFET can be bypassed by connecting the negative battery terminal to the bypass pin. (This terminal will also need to be connected to your logic supply ground.)

Dimensions

General specifications

File downloads

VNH3SP30 motor driver datasheet (586k pdf)

VNH2SP30 motor driver datasheet (670k pdf)

IRFR3707Z MOSFET datasheet (223k pdf)

Drill guide for VNH3SP30 Motor Driver Carrier MD01B (81k dxf)

This DXF drawing shows the locations of all of the board’s holes.