High-voltage, high-current Darlington transistor array with seven NPN Darlington pairs, in a SOIC-16 package. Each channel sinks up to 500 mA at 50 V, with integrated common-cathode freewheeling diodes (COM pin) for driving inductive loads and 2.7 kohm series base resistors that make the inputs directly TTL / 5 V CMOS compatible. The default way to drive relays, solenoids, unipolar stepper motors, lamps, and LED banks from an MCU's logic pins.

Pinout

Pin	Name	Type	Function
1	1B	input	Channel 1 Darlington base input. Drives channel 1 through an internal 2.7 kΩ series base resistor; TTL/5 V CMOS compatible. VI(on) ≤ 2.4 V typical for IC = 200 mA.
2	2B	input	Channel 2 Darlington base input. Drives channel 2 through the internal 2.7 kΩ base resistor; TTL/5 V CMOS compatible.
3	3B	input	Channel 3 Darlington base input. Drives channel 3 through the internal 2.7 kΩ base resistor; TTL/5 V CMOS compatible.
4	4B	input	Channel 4 Darlington base input. Drives channel 4 through the internal 2.7 kΩ base resistor; TTL/5 V CMOS compatible.
5	5B	input	Channel 5 Darlington base input. Drives channel 5 through the internal 2.7 kΩ base resistor; TTL/5 V CMOS compatible.
6	6B	input	Channel 6 Darlington base input. Drives channel 6 through the internal 2.7 kΩ base resistor; TTL/5 V CMOS compatible.
7	7B	input	Channel 7 Darlington base input. Drives channel 7 through the internal 2.7 kΩ base resistor; TTL/5 V CMOS compatible.
8	E	power_in	Common emitter shared by all seven Darlington channels. Typically tied to ground; all voltage references in the datasheet are with respect to this pin.
9	COM	power_in	Common-cathode node for the seven integrated flyback (freewheeling) clamp diodes. Connect to the positive supply of the inductive load (relay/solenoid/motor supply, up to 50 V) to clamp inductive kickback.
10	7C	output	Channel 7 Darlington open-collector output. Sinks up to 500 mA per channel to the common emitter (pin 8); VCE(sat) ≈ 1 V at 200 mA. Withstands 50 V off-state.
11	6C	output	Channel 6 Darlington open-collector output. Sinks up to 500 mA; 50 V off-state rating.
12	5C	output	Channel 5 Darlington open-collector output. Sinks up to 500 mA; 50 V off-state rating.
13	4C	output	Channel 4 Darlington open-collector output. Sinks up to 500 mA; 50 V off-state rating.
14	3C	output	Channel 3 Darlington open-collector output. Sinks up to 500 mA; 50 V off-state rating.
15	2C	output	Channel 2 Darlington open-collector output. Sinks up to 500 mA; 50 V off-state rating.
16	1C	output	Channel 1 Darlington open-collector output. Sinks up to 500 mA; 50 V off-state rating.

Key specifications

Parameter	Value
Type	7-channel Darlington transistor array
Output current	500 mA per channel
Output voltage	50 V
Inputs	TTL / 5 V CMOS (2.7 kΩ series base R)
Inductive loads	Common-cathode freewheeling diodes (COM)
Channels	7
Package	SOIC-16
Body (L×W×H)	9.9 × 3.9 × 1.75 mm

Ordering variants

Same part, different packaging or reel option.

ULN2003AD (SOIC-16, tube)
ULN2003ADR (SOIC-16, tape & reel)

CAD (KiCad official)

Symbol: Transistor_Array:ULN2003
Footprint: Package_SO:SOIC-16_3.9x9.9mm_P1.27mm
3D model: SOIC-16 (KiCad packages3D)

Provenance

Data extracted from the manufacturer datasheet, not a distributor listing:

Datasheet: Texas Instruments datasheet (42 pp, sha256 0151daa4ffa9135f, retrieved 2026-08-17, tier: manufacturer)
Extractor: ds2sf (Claude) — every pin and dimension is cited to a datasheet page; refuses to fabricate.
CAD: KiCad official libraries (CC-BY-SA 4.0).

Datasheet PDF