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The ULN2003ADR is a 7-channel Darlington transistor array integrated circuit in an SOP-16 (SOIC-16) surface-mount package. Each channel consists of an NPN Darlington pair rated for 500 mA continuous collector current, with a collector-emitter breakdown voltage of 50 V. Common-cathode clamp diodes are integrated across each output to suppress inductive kickback when driving relays, solenoids, and motors. Each input includes a 2.7 kΩ series base resistor, allowing direct interface with 5 V TTL and CMOS logic signals. The device is designed for industrial clients and electronics manufacturers requiring a compact, surface-mount load driver for relay control, stepper motor driving, lamp driving, and logic buffering applications.
Product Category | Darlington Transistor Array |
|---|---|
Number Of Channels | 7 Channels |
Collector-Emitter Breakdown Voltage (Vceo) | 50V |
Continuous Collector Current (Ic) | 500mA per channel |
Maximum Input Voltage (VI) | 30V |
Collector Leakage Current (Icex) | 50μA |
Diode Forward Voltage Drop (Vf) | 1.7V |
Reverse Diode Current (Ir) | 50μA |
Input Capacitance (Ci) | 15pF |
The device integrates seven independently controlled Darlington pairs, each capable of sinking up to 500 mA continuously. Channels may be paralleled for higher load current, subject to the total package power dissipation limit. This architecture replaces discrete transistor arrays and reduces component count on PCBA layouts.
Each output includes a common-cathode clamp diode that absorbs reverse electromotive force generated when inductive loads are switched off. This eliminates the need for external protection diodes in relay and solenoid drive circuits, simplifying board layout and reducing bill-of-materials line items.
A 2.7 kΩ series base resistor on each input allows the ULN2003ADR to connect directly to 5 V TTL and CMOS logic outputs without external current-limiting components. The input structure supports 3.3 V microcontroller signals when appropriate logic levels are observed.
The SOP-16 package measures approximately 9.9 mm × 3.9 mm × 1.5 mm, with a 1.27 mm lead pitch. It is compatible with standard automated SMT pick-and-place and reflow soldering processes, supporting high-volume electronics manufacturing lines.
The commercial-grade ULN2003ADR operates within a junction temperature range of 0°C to 70°C. This range covers indoor industrial control panels, consumer appliance control boards, and laboratory equipment environments.
When paralleling channels, designers must observe the total package power dissipation rating rather than simply summing per-channel current limits. Thermal derating should be applied according to the manufacturer datasheet for operation at elevated ambient temperatures.
The ULN2003ADR drives small signal relays and solenoid valves in industrial control boards and home automation modules. The 500 mA per-channel output covers most 5 V and 12 V miniature relay coils, and the integrated clamp diodes protect front-end logic from inductive voltage spikes.
Seven independent channels support multi-phase stepper motor winding control and small brushed DC motor driving in 3D printers, precision instrumentation, and automated sorting equipment. The 50 V collector-emitter breakdown voltage accommodates inductive motor loads within the rated voltage range.
The device drives indicator LEDs, small signal lamps, and low-power halogen lamps in appliance control panels and industrial status displays. Multiple channels can be configured to drive grouped indicator arrays simultaneously.
The ULN2003ADR serves as a high-current buffer between low-power TTL/CMOS logic circuits and heavy loads. It amplifies weak logic signals to drive longer PCB traces or external loads, isolating the front-end logic from load-side interference.
ULN2003A is the base part number for the Darlington array. The suffix "DR" indicates the SOP-16 (SOIC-16) surface-mount package in tape-and-reel format. The electrical specifications are identical across package variants.
Yes, each channel supports up to 500 mA continuous collector current, which covers most standard 5 V miniature relays. The integrated flyback diode absorbs coil reverse EMF without external components.
The internal 2.7 kΩ base resistor is designed for 5 V TTL/CMOS logic. With 3.3 V signals, the output saturation voltage may be slightly higher; designers should verify the required load current against the datasheet saturation characteristics.
The collector-emitter breakdown voltage (VCEO) is 50 V, supporting inductive loads with operating voltages below 50 V such as small stepper motors and solenoid valves.
Yes, channels may be paralleled to increase total sink current. However, the total package power dissipation must be observed, and thermal derating should be applied per the manufacturer datasheet for elevated ambient temperatures.
