STMicroelectronics L293D

Overview

L293D from STMicroelectronics is a monolithic high-voltage, high-current quad push-pull driver IC designed for bidirectional control of inductive loads. It features four independent channels with internal clamp diodes, 600 mA continuous output current per channel, 1.2 A non-repetitive peak current, TTL/DTL-compatible inputs, and integrated thermal shutdown. It is commonly used to drive DC motors, stepper motors, solenoids, and relays in robotics and industrial motion control.

For engineers reviewing the L293D datasheet, L293D pinout, L293D application, or L293D equivalent, key selection considerations include per-channel output current capability (600 mA), logic supply separation (VSS pin), enable-controlled dual-bridge operation, and built-in flyback diode protection for inductive switching.

Technical Context

The L293D integrates two independent H-bridge sections-each comprising two complementary push-pull drivers-with dedicated enable inputs (pins 1 and 11) enabling synchronous channel activation. Its logic supply (VSS, pin 20) is electrically isolated from the motor supply (VS, pin 10), allowing 5 V logic interfacing with up to 36 V motor rails.

Each channel provides bidirectional current flow with source/sink capability, clamped by integrated fast-recovery diodes across outputs (pins 3/8/13/18). Thermal shutdown activates at ~150 °C junction temperature, and switching is rated up to 5 kHz with rise/fall times ≤250 ns and propagation delays ≤750 ns (turn-on).

Key Specifications

Pinout & Package

The L293D is packaged in a 16-pin plastic DIP (Powerdip, 12+2+2 configuration) with pins 4, 5, 12, and 13 internally connected as a common thermal pad for heatsinking. Pin 10 supplies motor voltage (VS), pin 20 is absent (DIP version uses pin 8 for VSS), and pin 16 is GND.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar quad H-bridge driver applications.

Compared with TB6612FNG and SN754410, the L293D offers integrated protection and proven reliability in educational and prototyping contexts, while trading off efficiency for ease of use - making it ideal where layout simplicity and robustness outweigh power density requirements.

Availability

L293D is available at Aetrix Electronics and suitable for robotics actuation, industrial relay control, stepper motor indexing, and lab equipment motion control requiring stable component supply and long-term production support.

Supply support for L293D includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, specializing in power management, analog, microcontrollers, and automotive-grade ICs.

The L293D belongs to ST's legacy power driver product line, engineered specifically for cost-sensitive, medium-power motion control applications where integration, ruggedness, and ease of interface are prioritized over ultra-low power or high-frequency switching.

FAQ

What is the maximum safe operating voltage for the L293D motor supply (VS) pin?

The absolute maximum VS rating is 36 V, but sustained operation above 24 V increases junction temperature and reduces safe continuous output current. At 36 V, derating to ≤400 mA per channel is recommended with adequate PCB copper heatsinking and ambient temperature ≤50 °C.

Can the L293D drive a bipolar stepper motor in full-step mode?

Yes - the L293D can drive a 4-wire bipolar stepper motor in full-step mode using two H-bridges (channels 1–2 and 3–4), with each bridge controlling one motor phase. Microstepping is not supported due to lack of current regulation or PWM current control.

Why does the L293D have separate VSS and VS supply pins?

VSS powers the internal logic and input buffers (typically 5 V), while VS powers the output drivers (up to 36 V). This separation prevents motor supply noise from disrupting logic-level signals and allows mixed-voltage system design - e.g., 3.3 V MCU control with 12 V motor rail.

Is heatsinking required for continuous 600 mA operation per channel?

Yes - at 600 mA per channel and 24 V VS, power dissipation exceeds 1.5 W per H-bridge. The DIP package's R_{th j-amb} is 80 °C/W; without a thermal pad connection to ≥6 cm² copper pour, junction temperature will exceed 125 °C at 25 °C ambient. Use pins 4/5/12/13 soldered to large copper areas.