STMicroelectronics L293DD

Introduction to the L293DD Dual Motor Driver Integrated Circuit

The L293DD from STMicroelectronics is a monolithic, high-voltage, high-current four-channel motor driver integrated circuit (IC) designed to facilitate the control of inductive loads such as bipolar stepper motors, brushed DC motors, relays, and solenoids. Optimized for use with standard DTL or TTL logic levels, the L293DD offers a robust and reliable interface between low-level control circuitry and high-power actuator elements. Housed in a compact 20-pin surface-mount SOIC package, the device supports an output current of 600mA per channel with peak capability up to 1.2A for short-duration pulses, making it suitable for a broad range of industrial and consumer motor control applications.

Main Advantages of the L293DD in Motor Driving Tasks

The L293DD’s architecture consists of four independent half-bridge drivers, enabling flexible configuration as dual full bridges for bidirectional control of two DC motors or as a single quad-channel driver. Its integrated output clamping diodes simplify external component count when driving inductive loads, and the enable inputs for each pair of channels support straightforward logic interfacing and control. The L293DD supports supply voltages (Vs) from 4.5V to 36V and logic supply voltages (Vss) from 4.5V up to 7V, expanding compatibility with diverse logic families. Additional features include:

Output current capability: 600mA per channel (1.2A peak, non-repetitive)

Over-temperature protection circuitry to enhance reliability in demanding conditions

Enable facility for each channel pair

High noise immunity (accepts logic ‘0’ down to 1.5V)

Internal clamp diodes for safe operation with inductive loads

Switching frequency capability up to 5 kHz for typical motor control

Operating Specifications and Maximum Ratings of the L293DD

A comprehensive understanding of the L293DD’s electrical parameters is critical for system designers:

Supply Voltage Range (Vs): 4.5V to 36V

Logic Supply Voltage Range (Vss): 4.5V to 7V

Output Current per Channel: Continuous 600mA, Peak (100μs, non-repetitive) 1.2A

Input Voltage: up to 7V

Enable Voltage: up to 7V

Saturation Voltage: 1.2V–1.8V max (at 0.6A, sink or source configuration)

Quiescent Supply Current (typical): 2–24mA depending on state and loading

Absolute maximum temperature ratings extend from –40°C to +150°C (junction/storage), ensuring robust operation in varied environments. This makes the L293DD suitable for professional-grade equipment and temperature-sensitive implementations.

L293DD Pinout and Functional Description

The L293DD is available in a 20-pin SOIC package with a pinout optimized for PCB design and thermal performance. Each channel comprises dedicated input, output, and enable signals, facilitating both independent and grouped operation. The grouping of center pins for heat dissipation provides effective thermal management without the need for complex PCB layout adjustments.

A typical application would employ two channels each for push-pull operation of two DC motors, with the enable and input pins providing straightforward interfacing to microcontroller logic. Internal logic separation (Vss) and power (Vs) supply inputs allow for mixed-voltage operation environments—ideal when processor and actuator power rails are dissimilar.

Heat Dissipation Strategies and Package Information for L293DD

Thermal considerations play a significant role in high-current designs. The SO20 package’s low thermal resistance (junction-ambient of 50°C/W with appropriate heatsinking) enables efficient dissipation of heat generated during high-load operation. The central heatsink-connected pins can be tied directly to copper pours or dedicated heatsink surfaces on the PCB, further improving reliability under continuous operation. Footprint and mechanical dimensions (20.0 × 8.8 mm body, 7.5 mm width) align with industry-standard surface-mount handling and assembly practices.

Practical Applications of the L293DD in System Designs

The L293DD’s fully integrated driver stages and high current capability make it a popular solution for direct control of small- and medium-sized DC motors and stepper motors in office equipment, industrial automation modules, and consumer robotics. Its on-board protection features allow direct connection to inductive loads such as relays and solenoid actuators, minimizing the need for ancillary circuitry.

Engineers commonly use the L293DD in motorized locks, valve controls, pan/tilt camera modules, and basic mobile robot platforms. Its high-temperature tolerance and robust design also make it suitable for automotive applications and environmental control systems.

Alternative and Substitute ICs for the L293DD

When designing systems around the L293DD, engineers and procurement specialists may consider alternative devices for second-sourcing or performance enhancement:

L293D (STMicroelectronics): Offers similar functionality in a smaller 16-pin DIP or SO package but with lower power dissipation capability.

SN754410 (Texas Instruments): A widely used compatible device in a through-hole or SOIC package with similar voltage and current ratings.

L298N (STMicroelectronics): For applications requiring higher current (up to 2A per channel) and more robust thermal management, though at the cost of a larger package.

DRV8833 (Texas Instruments): A modern dual H-bridge driver with integrated protection, lower supply voltages, and higher efficiency, for applications not requiring the L293DD’s full voltage range.

Selection should consider exact form factor, electrical ratings, and features required by the target application.

Regulatory Standards and Certifications Related to the L293DD

The L293DD complies with leading industry safety and environmental standards. It is RoHS-compliant (Restriction of Hazardous Substances) and has a moisture sensitivity level (MSL) of 3 (168 hours), facilitating safe processing in standard lead-free reflow soldering environments. The device is classified under ECCN EAR99 for export and is unimpacted by current REACH regulations—useful information for global supply chain management and product regulatory compliance.

Conclusion

: Evaluating the L293DD Motor Driver in Component Selection

The L293DD from STMicroelectronics stands as a reliable, versatile solution for low- to medium-power motor and inductive load driving needs. Its robust feature set, including high noise immunity, wide voltage and temperature ranges, and integrated protection, simplifies the design of many motion control and actuator subsystems. With industry-standard packaging, available footprints, and straightforward logic interfacing, the L293DD is well-positioned for use in legacy and new designs alike. Alternative models are available for applications requiring either higher performance or a different package footprint, supporting flexible sourcing in volume and long-term program management. Product selection and procurement teams will find the L293DD an enduring, trusted solution for a broad set of motor control challenges.