ULN2004AD

Overview

The ULN2004AD is a high-voltage, high-current Darlington transistor array manufactured by Texas Instruments. It integrates seven open-collector Darlington pairs with common emitters within a single SOIC-Narrow-16 surface-mount package. Each channel supports a maximum continuous collector current of 300 mA and withstands peak currents up to 600 mA, operating at a collector-emitter voltage of 50 V. The device includes integrated suppression diodes for inductive load driving and features input pins positioned opposite the outputs to simplify printed circuit board layout. It operates within a temperature range of -20°C to +70°C.

Feature Summary

• Integrates seven independent NPN Darlington pairs with common emitters for multi-channel switching applications.
• Includes built-in clamping diodes across each output to suppress voltage spikes from inductive loads such as relays and solenoids.
• Features complementary pinout arrangement where inputs are located on one side and corresponding outputs on the other to facilitate routing.

Applications

• Relay driver circuits
• Stepper motor control interfaces
• High-current buffer stages for logic signals

Procurement Notes

Verify component authenticity through authorized distributors or direct manufacturer channels. Confirm the specific suffix 'AD' corresponds to the SOIC-16 package variant. Check for end-of-life status or obsolescence notices prior to finalizing procurement plans to ensure long-term supply stability.

Selection Notes

Select this component when a surface-mount solution is required for driving multiple inductive loads. Ensure the design accommodates the thermal dissipation limits inherent to the SOIC-16 package. Verify that the 50V rating and 300mA per-channel current capacity meet the specific load requirements of the target application.

Part Context

This part belongs to the ULN2004A family of high-voltage Darlington arrays. While the ULN2004AN provides a through-hole DIP-16 option, the ULN2004AD specifically denotes the surface-mount version. It shares functional similarities with the ULN2003 but is optimized for different logic input voltage levels, typically interfacing with CMOS or PMOS families.

Replacement Considerations

• ULN2004ADG4