ULN2003 Darlington Arrays, Stepper Driver Boards and 28BYJ-48 Kits

ULN2003 parts, driver boards and geared stepper-motor sets

Explore bare ULN2003-family Darlington transistor arrays, assembled ULN2003 stepper driver modules, 28BYJ-48 geared motors and motor-plus-board sets. This collection also contains related ULN2004/ULN2803 family options, mixed IC assortments and a small number of differently designed motor drivers. It is not a collection of identical seven-channel ICs: choose the actual variant to establish the part number, package, motor voltage, quantity and what arrives in the parcel.

What the ULN2003 does

A ULN2003-type device combines seven Darlington low-side transistor driver channels, enabling low-power logic to switch suitable external loads. The outputs sink current to ground; they are not push-pull H-bridges, independent power supplies or precision current-controlled stepper stages. The family is used in relay, lamp, solenoid and small unipolar stepper applications when the specific load and board are compatible. On common 28BYJ-48 driver boards, four input channels typically sequence four motor phases, and indicator LEDs may show those drive states. A board marked 'four phase' therefore need not contain four complete H-bridges or drive four independent motors.

Darlington stages have an on-state voltage drop and dissipate heat. Evaluate coil current, supply voltage, duty cycle, simultaneous channels, package thermal limits and the board's power routing against the exact selected device's datasheet. A 'high-power' or '500mA' seller headline is not a guarantee of 500mA continuously on every channel simultaneously. For inductive loads, verify the intended clamp-diode/common-pin arrangement in the manufacturer's circuit and the particular board layout; an LED indication circuit is not proof of a safe flyback design for arbitrary coils. A microcontroller output controls the driver input, not the motor winding directly.

Identify the item you are buying

• Bare DIP-16 ICs: selected ULN2003AN/APG variants are through-hole chips for sockets or soldered PCB assembly. Listings may offer a single model in packs of 10, 20, 50 or 100. A bare chip has no XH-5P motor connector, supply terminal or indicator LED.
• Surface-mount ICs: ULN2003ADR/AG, ULN2003D1013TR, ULN2003AIDR SOIC/SOP-16 and ULN2003APWR/AIPWR TSSOP-16 appear in separate listings or variant menus. A SOP/SOIC footprint, narrow TSSOP footprint and 16-pin DIP are not interchangeable on a board. Check suffix, pin dimensions, packing quantity and exact part specification.
• ULN2004 and ULN2803 alternatives: several multi-model pages allow ULN2004AN/ADR/AFWG or ULN2803/ULN2804 in place of ULN2003. Input-network characteristics can differ between ULN2003 and ULN2004 family devices, while ULN2803 typically has eight driver channels and a different package/pin count. Treat them as distinct options, not spelling variants or pin-for-pin substitutes.
• Assembled stepper modules: blue and green driver-board choices are typically printed circuit boards using a ULN2003-family IC, a motor connector and phase-indicator LEDs. Check the selected board's input header, motor connector, mounting dimensions, supply arrangement and voltage designation. A module-only option does not include a 28BYJ-48 motor.
• 28BYJ-48 motors: 5V and 12V geared five-wire motor options coexist. 'DC 5V stepper motor' or 'DC 12V stepper motor' can be a motor-only variant; '5V and Driver board' or '12V and Driver board' is a different selection. Match the motor's rated voltage and winding connections to the particular board and supply. Gear ratio, torque, step count and speed vary with motor specification, drive sequence and load; do not treat a generic 1/64 or 5.625-degree seller figure as a guaranteed output-shaft resolution for every variant.
• Sets and accessories: 1-, 2-, 3-, 5-, 10-, 15-, 20-, 25- and 30-set options appear across listings. Other variant menus distinguish motor only, driver only, motor-plus-driver, male-to-female jumper leads, USB-to-DC cable and 'Suit Cable'. A photographed accessory or a title saying 'kit' does not make it part of every selected variant. One 10-set listing explicitly describes 10 motors plus 10 boards for its sole 'No plug' variant; verify the contents of other set options independently.

Do not confuse a menu of choices with a combined kit

A page titled '28BYJ-48 + ULN2003' can offer '28BYJ-48 Motor', 'ULN2003 Module' and '28BYJ-48 and ULN2003' as mutually exclusive variants. Another offers '5V motor', '12V motor', 'Driver board for 5V', 'Driver board for 12V' and motor-with-board choices. Color choices such as 'ULN2003 Blue' and 'ULN2003 Green' identify driver-board variants, not a pair of boards unless the selected quantity says so. Read the selected variant and the product's package list together, particularly where a title advertises 10 pieces but a variant denotes only one component type.

Multi-model chip pages may list ULN2001/ULN2002/ULN2003/ULN2004 or ULN2803/ULN2804 alongside each other; only the selected model ships. Some broad listings include a ULN2003 option beside 74HC4051, MCP3008, discrete transistors, L293D or PWM-controller ICs. Separate 60-, 75- and 85-piece assortment boxes contain a mix of timer, analog, logic, optocoupler and driver parts, not 60, 75 or 85 ULN2003 chips. Check the actual box bill of materials rather than inferring each chip's count from the assortment total.

Related motor drivers in this collection

A few listings are L293D ICs, Arduino-format H-bridge shields or L293D-based robot-car kits. L293D H-bridge architecture differs from the ULN2003's low-side Darlington outputs, so a robot shield, a 16-pin IC and a ULN2003 stepper board do not share the same interface or motor compatibility by default. A separate SA8302 module is advertised as replacing ULN2003 for some 28BYJ-48 projects; its H-bridge architecture and 'with shell' versus 'no shell' options need their own controller and motor-compatibility checks. A 12A dual-channel H-bridge module mentioned near L298N/BTS7960 is also a separate class of motor driver, not a higher-current ULN2003. These entries remain visible here so buyers can identify the differences rather than accidentally substituting them.

Engineering selection checklist

1. First select the assembly level: IC only, driver PCB only, geared motor only, motor-plus-driver set, cable/accessory, assorted IC box or alternative driver. Confirm the selected variant, not just the product title or photograph.
2. Match voltage to the motor: a 5V 28BYJ-48 and a 12V 28BYJ-48 are not interchangeable simply because the same family of connector is pictured. Verify the actual winding rating, board version, supply input and controller logic requirements.
3. Check drive topology: the usual five-wire unipolar motor arrangement is not automatically compatible with a bipolar stepper's four-wire drive requirements. Verify the motor lead count, winding configuration, connector polarity and control sequence against the motor and board documentation. Do not infer wiring from wire colors across vendors.
4. Check load and thermal budget: inspect coil current, start/stall behavior, Darlington voltage drop, number of active channels and the datasheet limits for the chosen IC and board. Do not equate a maximum rating with a universal continuous rating.
5. Check package and interface: select DIP, SOIC/SOP or TSSOP to match the PCB footprint. For modules, verify connector type, pin order, available supply and I/O levels; 'for Arduino' means a possible control application, not a universal plug-and-play electrical guarantee.
6. Count included units: '10PCS ULN2003AN', '10 set motor + board', 'Motor-1PCS' and 'ULN2003 Module' refer to different shipments. Review variant, pack count and individual product description before planning production or classroom inventory.

Typical buying paths

For a breadboard or socketed repair, start with the exact ULN2003 DIP-16 suffix and required pack count. For a compact manufactured PCB, select the specified SOIC/SOP or TSSOP package only after confirming pad geometry. For a 28BYJ-48 demonstration, select the motor's 5V or 12V version and an appropriately documented driver board, then check whether the chosen option includes both. For a mixed-parts lab kit, look at the stated contents of the assortment rather than assuming all included chips are motor drivers. In every case, the device-specific datasheet and selected product variant govern electrical design and delivery contents; this collection guide does not replace either.