L293B

Overview

The L293B is a quad push-pull driver manufactured by STMicroelectronics, designed for driving inductive loads such as DC motors and relays. It operates within a supply voltage range of 4.5 V to 36 V and delivers a continuous output current of 1 A per channel with a peak non-repetitive current of 2 A. The device features four independent channels controlled by TTL-compatible logic inputs, with pairs enabled via inhibit signals. It utilizes a separate logic supply input to allow operation at lower voltages, reducing internal dissipation. Packaged in a 16-pin plastic DIP, it includes overtemperature protection and high noise immunity.

Feature Summary

• Quad push-pull architecture providing independent control for four output channels
• Separate logic supply input enabling lower voltage operation for reduced power dissipation
• Integrated overtemperature protection circuitry for thermal safety
• High noise immunity on TTL-compatible logic inputs

Applications

• Brushed DC motor control systems
• Relay and solenoid driving circuits
• Industrial automation actuators
• Bipolar stepper motor interfaces

Procurement Notes

Verify the specific package variant against the datasheet to ensure compatibility with PCB footprint requirements. Confirm that the operating environment remains within the specified temperature range to maintain performance integrity. Check for any regional compliance certifications required for the target market. Ensure proper heat sinking strategies are implemented if continuous peak currents are approached, as thermal management is critical for long-term reliability in enclosed assemblies.

Selection Notes

Select this component when a quad-channel driver with moderate current capacity is required for bidirectional motor control. The separate logic supply feature makes it suitable for interfacing low-voltage microcontrollers with higher voltage motor loads. Consider the 16-pin DIP package for through-hole prototyping or applications where surface-mount options are not preferred. Evaluate thermal constraints carefully, as the device relies on PCB copper area for heat dissipation due to the lack of an exposed pad in this package style.

Part Context

The L293B belongs to the L293 family of motor drivers produced by STMicroelectronics. It serves as a robust solution for controlling multiple inductive loads simultaneously. Unlike variants with integrated diodes, the L293B requires external freewheeling diodes for inductive load protection. It is commonly paired with stepper motor controllers like the L297 for complete motion control solutions. The device represents a standard interface between digital logic and analog power stages in embedded systems.

Replacement Considerations

• L293E

FAQ

Does the L293B include internal freewheeling diodes?

No, the L293B does not integrate internal freewheeling diodes. External diodes must be connected across inductive loads to protect the outputs from voltage spikes.

How is the enable function controlled?

The channels are enabled in pairs. Each pair has a dedicated inhibit input; a high level enables the corresponding outputs, while a low level disables them regardless of the logic inputs.