Almost nobody buys a bare L298N chip — what actually turns up in every beginner robot-car kit is a small red or black breakout board built around it, with screw terminals for the motors and power, and a header for logic connections. That board, not the chip datasheet, is what this covers, since the board adds a voltage regulator and a jumper that the bare chip doesn’t have — and that jumper is where most first-time mistakes with this part happen.
What it does
The L298 is a dual H-bridge — two independent circuits, each capable of driving a DC motor forwards, backwards, or letting it coast, by switching which side of the motor is connected to positive and which to ground. One L298N board drives two DC motors independently, or one 4-wire bipolar stepper motor using both H-bridges together.
Pinout (breakout board)
Terminal blocks on one edge, control header on the other:
| Pin / terminal | Name | What it does |
|---|---|---|
| Screw terminal | +12V (VMS) | Motor supply voltage, up to 35V depending on the specific board’s rating — this is what actually powers the motors, not the logic |
| Screw terminal | GND | Ground, shared between motor supply and logic |
| Screw terminal | +5V (VSS) | 5V logic supply — supplied by the board’s onboard regulator if the 5V jumper is fitted, or an input if it’s removed (see below) |
| Screw terminal | OUT1, OUT2 | Motor A output — wire one DC motor across these two |
| Screw terminal | OUT3, OUT4 | Motor B output — wire the second DC motor across these two |
| Header pin | ENA | Enable Motor A. PWM this pin for speed control, or bridge the jumper to run Motor A at full speed whenever it’s directionally enabled |
| Header pin | IN1, IN2 | Direction control for Motor A — HIGH/LOW and LOW/HIGH drive it in opposite directions, LOW/LOW or HIGH/HIGH brake it |
| Header pin | IN3, IN4 | Direction control for Motor B, same logic as IN1/IN2 |
| Header pin | ENB | Enable Motor B, same as ENA |
The 5V jumper — the single most important thing on this board
Next to the power terminals there’s usually a small jumper labelled 5V-EN or similar, sitting across three pins. With it fitted, the board’s onboard 78M05-style regulator generates 5V logic power from the same 12V input feeding the motors, so a single supply runs everything. With it removed, that onboard regulator is disconnected, and the board expects a separate 5V logic supply fed into the VSS terminal directly.
Leaving the jumper fitted while feeding the board more than about 12V is a common way these boards die or run hot enough to shut down. The onboard regulator is a small linear part not built to dissipate much power, and asking it to drop a much higher input voltage down to 5V generates heat proportional to that voltage difference — fine at 12V, a real problem well above it. If a project’s motor supply needs to be higher than 12V, remove the jumper and feed the logic side its own clean 5V separately (from a microcontroller’s regulated 5V rail, for instance), rather than asking the onboard regulator to do a job it isn’t sized for.
Wiring a basic setup
- Motor supply into the +12V and GND terminals — a battery pack or bench supply appropriate for the motors being driven, not the microcontroller’s own 5V rail.
- Two DC motors across OUT1/OUT2 and OUT3/OUT4.
- IN1–IN4 to four digital output pins on the microcontroller.
- ENA and ENB to PWM-capable pins if variable speed is wanted, or left jumpered for simple on/off full-speed control.
- GND shared between the motor supply, the logic supply, and the microcontroller — a genuinely easy step to forget when the motor battery and the microcontroller are powered from two separate sources, and forgetting it is a common reason a board with correct-looking wiring does nothing at all.
Why it runs warm and loses voltage under load
The L298 is built from bipolar transistors, not MOSFETs, and each H-bridge has a real voltage drop across it — commonly cited as somewhere around 2V total between the supply and what the motor actually sees, which only gets worse under higher current. A motor rated for 12V run from a 12V supply through an L298N will genuinely see noticeably less than 12V at the motor terminals, and the board will run warm doing it — this is normal operation for this specific chip, not a fault, but it’s worth knowing if a motor seems weaker than its rating suggests. Newer MOSFET-based driver modules (built around chips like the TB6612FNG) don’t have this same voltage-drop penalty, at the cost of usually handling less current — worth knowing if a project is sensitive to the lost voltage, though the L298N remains the more common, cheaper, and higher-current choice for beginner robot-car kits.
Common mistakes
Leaving the 5V jumper on with a high-voltage motor supply. Covered above — the most common way to cook the onboard regulator.
No common ground between motor supply and logic supply. If the motors are powered from a separate battery to the microcontroller, tie their grounds together, or nothing on the logic side has a stable reference to switch against.
Expecting the full supply voltage at the motor. The chip’s own voltage drop, covered above, means the motor sees less than what’s fed into +12V — factor this in rather than assuming a mismatch means something’s wired wrong.
Stalling a motor for too long. A stalled DC motor draws far more current than a spinning one, and the L298N’s thermal protection will shut the chip down if it gets hot enough — if outputs suddenly stop responding mid-project, let the board cool before assuming it’s dead.
If you don’t have one on the bench already, a L298N motor driver board with a heatsink and screw terminals is the standard way in for a first robot-car or stepper project.
