STMicroelectronics ULN2067B

Overview

ULN2067B from STMicroelectronics is a quad NPN Darlington transistor array with integrated clamp diodes, designed for high-voltage, high-current switching of inductive loads such as relays, solenoids, and lamps. It delivers 1.5 A per channel, sustains 50 V (V_CE(SUS)), features 3 kΩ input resistors, and operates with 6–15 V CMOS/PMOS logic inputs.

For engineers reviewing the ULN2067B datasheet, ULN2067B pinout, ULN2067B application, or ULN2067B equivalent, key selection criteria include output sustaining voltage, input resistor value, clamp diode integration, thermal derating at 70 °C ambient, and compatibility with wide-range logic supply voltages.

Technical Context

The ULN2067B integrates four independent Darlington pairs with built-in flyback diodes connected anode-to-emitter and cathode-to-V_CC, enabling safe commutation of inductive loads without external protection components. Each channel includes a 3 kΩ series input resistor to limit drive current and ensure direct interface with 6–15 V logic sources.

It uses a common-emitter output configuration with all emitters tied internally to Pin 8 (GND), requiring external load connection between V_CC and collector outputs. Thermal performance is defined by 4.3 W total power dissipation at T_PINS = 90 °C and R_thJA dependent on PCB copper area.

Key Specifications

Pinout & Package

ULN2067B is housed in a PowerDIP-16 package (20.0 mm × 8.80 mm, 2.54 mm pitch), with GND (Pin 8) and V_CC (Pin 10) positioned for optimal thermal path and noise isolation. Pins 1–7 and 9–16 are arranged in dual-row configuration with staggered leads for mechanical stability.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar quad Darlington switching applications.

Compared with ULN2065B and ULN2069B, the ULN2067B uniquely balances 6–15 V logic compatibility, integrated clamping, and 3 kΩ input impedance-making it optimal for industrial PMOS/CMOS systems where external diodes are undesirable and drive voltage exceeds 5 V.

Availability

ULN2067B is available at Aetrix Electronics and suitable for industrial relay control, automotive lamp drivers, stepper motor phase switching, and printer solenoid actuation requiring stable component supply and long-lifecycle support.

Supply support for ULN2067B includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, specializing in power management, analog, microcontrollers, and discrete devices for industrial, automotive, and consumer markets.

The ULN2067B belongs to ST's high-voltage Darlington array product line, engineered specifically for robust, low-component-count interfacing between logic controllers and rugged inductive loads in factory automation and transportation equipment.

FAQ

What logic families can directly drive the ULN2067B inputs?

The ULN2067B inputs are designed for 6–15 V CMOS and PMOS logic families. With its internal 3 kΩ input resistor, it draws approximately 2 mA at 6 V and 5 mA at 15 V - eliminating the need for external current-limiting resistors. TTL or 5 V logic cannot reliably activate the device without level shifting or additional buffering.

Can ULN2067B drive inductive loads without external diodes?

Yes - the ULN2067B integrates clamp diodes connected from each collector to V_CC (Pin 10). These diodes safely dissipate flyback energy during inductive load turn-off, provided V_CC is connected to the positive side of the load supply. No external diodes are required for standard relay or solenoid switching.

How does thermal performance change with PCB layout?

Thermal resistance (R_thJA) drops significantly when Pins 8 (GND) and 10 (V_CC) are soldered to ≥2 cm² copper areas. At T_AMB = 70 °C, power dissipation is limited to 1 W without heatsinking but rises to 4.3 W when pin temperatures are held at 90 °C via proper copper pour or external heatsink attachment.

Is ULN2067B suitable for automotive under-hood applications?

No - the ULN2067B is specified for −20 °C to +85 °C ambient operation and is not qualified as AEC-Q100 automotive grade. While it may function in benign cabin environments (e.g., infotainment backlight control), it is not recommended for under-hood, engine-control, or safety-critical systems where extended temperature range and qualification testing are mandatory.