L298

Dual Full-Bridge (H-Bridge) Motor Driver IC. Originally designed by SGS-Thomson (now STMicroelectronics), it is engineered to control high-voltage, high-current inductive loads like DC motors, stepper motors, relays, and solenoids using standard TTL logic levels - Operating Supply Voltage (\(V_{S}\)): Up to 46V (Absolute maximum rating of 50V).Logic Supply Voltage (\(V_{SS}\)): 4.5V to 7V.Output Current (Per Channel): 2A continuous DC operation, with a repetitive peak current capability up to 2.5A, and non-repetitive peaks up to 3A.Total Power Dissipation (\(P_{tot}\)): Up to 25W at a case temperature of 75°C.Package Formats: Multiwatt15 (through-hole vertical package with a metal tab for heat sinking) and PowerSO20 (surface-mount version).Internal Architecture & PinoutThe chip embeds two independent H-bridges. Each bridge can be enabled or disabled independently via dedicated enable pins (Enable A and Enable B), allowing for easy pulse-width modulation (PWM) speed control.The chip features Current Sensing Pins (Sense A and Sense B). The emitters of the lower transistors in each bridge are exposed externally, allowing you to connect a low-value resistor to ground to monitor and control the motor current.Common ApplicationsDual DC Motor Control: Drives two independent brushed DC motors with bi-directional rotation and speed control.Stepper Motor Control: Drives one 2-phase or 4-phase bipolar stepper motor by sequencing the inputs.High-Current Switching: Acts as a solid-state driver for large solenoids or heavy relays.Usage Tips & Modern ConsiderationsFlyback Diodes Required: The raw L298 IC does not have integrated flyback protection diodes. You must add 8 external fast-recovery diodes (such as 1N5819 or 1N4007) to protect the chip from inductive voltage spikes, unless you are using a pre-built red L298N module board which usually integrates them.Heat Sinking: Because the L298 uses outdated Bipolar Junction Transistor (BJT) technology rather than modern MOSFETs, it has a high saturation voltage drop (often losing 1.5V to 3V as pure heat). It will get very hot under heavy loads and always requires a substantial heatsink.Modern Alternatives: For new designs, engineers often replace the L298 with more efficient MOSFET-based alternatives like the TB6612FNG or DRV8833, which run much cooler and do not require bulky heatsinks