ULN2003 Stepper Motor Driver

Robust 7‑Channel Darlington Driver for Precision Stepper Control

The ULN2003 stepper motor driver is a high‑current, low‑voltage interface designed to seamlessly translate standard 2.5–5V logic signals into the robust power required by small to medium‑sized stepper motors and relay arrays. Built on a 7‑channel Darlington transistor array, each output can sink 500 mA at voltages up to 50 V, making it ideal for inexpensive unipolar stepper motors like the 28BYJ‑48, as well as for driving relays, solenoids, and other inductive loads.

With its open‑collector outputs and built‑in protection diodes, the ULN2003 eliminates the need for external flyback diodes, simplifying board design and reducing component count. Its compact surface‑mount or through‑hole package fits comfortably in tight spaces, and its low quiescent current minimizes heat generation during extended operation.

• Key Spec 1: 7‑Channel Darlington Array – individually addressable open‑collector outputs for multiple drivers
• Key Spec 2: Current Capability – up to 500 mA per channel, 50 V rated for high‑voltage stepper motors and relays
• Key Spec 3: Low‑Voltage Logic Input – 2.5–5 V TTL/CMOS compatible, 30 mA maximum input current
• Common Use Case: Driving 28BYJ‑48, 2007‑28BYJ‑48, and similar unipolar stepper motors in robotics, CNC routers, and automated conveyor systems