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Home > Products > Discrete Semiconductor Products > Transistors > Bipolar (BJT) > Bipolar Transistor Arrays

STMicroelectronics ULN2075B

Name: ULN2075B
Brand: STMicroelectronics
SKU: ULN2075B
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: ULN2075B

Manufacturer:: STMicroelectronics

Category:: Bipolar Transistor Arrays

Package:: 16-PowerDIP (0.300", 7.62mm)

Datasheet:: ULN2075B.pdf

Description:: TRANS 4NPN DARL 80V 1.75A 16DIP

Quantity:: RFQ Add To RFQ list

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Product details

Overview

ULN2075B from STMicroelectronics is a quad NPN Darlington transistor array in PowerDIP-16 package, designed for high-voltage, high-current switching with isolated emitter outputs. It delivers 1.5 A per channel, supports 80 V output breakdown voltage, sustains 50 V at 100 mA, features 350 Ω input resistors, and operates from −20 °C to +85 °C ambient - used in industrial relay drivers and solenoid control.

For engineers reviewing the ULN2075B datasheet, ULN2075B pinout, ULN2075B application, or ULN2075B equivalent, key selection criteria include isolated Darlington configuration (no common emitter), 350 Ω integrated input resistors, absence of clamp diodes, compatibility with 5 V TTL/CMOS logic, and suitability for emitter-follower load configurations requiring independent emitter access.

Technical Context

The ULN2075B implements four independent NPN Darlington pairs with isolated emitters - unlike ULN2065B/2067B/2069B - enabling emitter-follower operation and external diode placement. Each channel includes a 350 Ω series input resistor and no internal suppression diodes.

It is optimized for direct logic-level interfacing without external base resistors, with VI(ON) ≤ 2.5 V at IC = 1 A and VCE(SAT) ≤ 1.5 V at IC = 1.5 A and IB = 2.25 mA. Input current ranges from 1.4 mA to 9.6 mA across 2.4–3.75 V input range.

Key Specifications

Parameter	Value and Actual Design Meaning
Output current	1.5 A per channel - supports driving relays, lamps, and small motors directly
Breakdown voltage	80 V VCEX - enables safe operation with inductive loads up to 80 V supply rails
Sustaining voltage	50 V at 100 mA - ensures stable conduction under sustained load conditions
Input resistor	350 Ω - eliminates need for external base resistors when driven by 5 V logic
VCE(SAT)	1.5 V max at 1.5 A - limits power dissipation to ≤2.25 W per active channel
Operating temperature	−20 °C to +85 °C - qualified for industrial ambient environments

Pinout & Package

ULN2075B uses PowerDIP-16 package with 0.3-inch wide body, 2.54 mm pin pitch, and standard through-hole mounting. Pin 1 is top-left corner (notch side), with pins numbered left-to-right on top row (1–8), then right-to-left on bottom row (9–16).

Pin/Terminal	Circuit Role	Design Meaning
1, 3, 5, 7	Input (IN1–IN4)	Logic-level inputs with integrated 350 Ω series resistors - accept 5 V TTL/CMOS directly
2, 4, 6, 8	Output (OUT1–OUT4)	Collector terminals of Darlington pairs - connect to load anodes or high-side switches
9, 11, 13, 15	Emitter (E1–E4)	Isolated emitter terminals - enable emitter-follower use, external diode placement, or floating load returns
10, 12, 14, 16	GND	Ground reference for substrate and input circuitry - must be connected to system ground

Key Features

Feature	Design Value
Isolated Darlington emitters	Four independent emitter terminals allow emitter-follower configuration and custom flyback diode routing
No internal clamp diodes	Enables user-selected external diode type (e.g., fast recovery, TVS) for optimized inductive load protection
Integrated 350 Ω input resistors	Eliminates external base drive resistors - simplifies PCB layout and reduces BOM count
80 V output breakdown rating	Supports 24 V and 48 V industrial control rails with margin for voltage transients

Applications

Industrial Relay Drivers

DC Solenoid Control

Use Scenario: Driving 24 V DC electromagnetic relays in PLC I/O modules with discrete logic control.

IC Role / Device Role / Timing Role: High-current switch translating 5 V microcontroller GPIO into 1.5 A relay coil drive.

Use Value: Isolated emitters permit direct connection of relay coil return to separate low-noise ground, reducing crosstalk between channels.

Use Scenario: Controlling pneumatic valve solenoids in factory automation systems with 48 V supply rails.

IC Role / Device Role / Timing Role: Darlington switch providing 1.5 A peak current to energize 48 V solenoids with <1.5 V saturation drop.

Use Value: 80 V breakdown rating accommodates back-EMF spikes during de-energization without external snubbing.

LED Array Drivers

Stepper Motor Phase Switches

Use Scenario: Sequencing high-brightness LED strings (e.g., signage, machine vision lighting) using microcontroller PWM.

IC Role / Device Role / Timing Role: Constant-current sink switch controlling LED cathode paths with precise timing via logic-level input.

Use Value: 350 Ω input resistors ensure clean 5 V logic edge response, supporting PWM frequencies up to 100 kHz.

Use Scenario: Driving unipolar stepper motor phases in CNC motion controllers with discrete step/direction logic.

IC Role / Device Role / Timing Role: Four-channel high-side switch enabling phase sequencing with independent emitter returns for current sensing.

Use Value: Isolated emitters allow shunt resistor placement between each emitter and ground for per-phase current monitoring.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
ULN2065B	Includes integral clamp diodes; common emitter (pin 8); 350 Ω input resistors	Designed for generic inductive load switching where shared emitter and built-in diodes simplify design	Select ULN2065B when clamp diodes are required and emitter isolation is unnecessary
ULN2067B	3 kΩ input resistors; compatible with 6–15 V CMOS/PMOS; common emitter (pin 8); includes clamp diodes	Targeted at higher-voltage logic families and systems requiring wider input voltage tolerance	Select ULN2067B when driving from 12 V logic or when common-emitter topology suffices

Compared with ULN2065B and ULN2067B, ULN2075B uniquely provides isolated emitters and no internal diodes - making it the only choice among these for emitter-follower configurations, per-channel current sensing, or custom transient suppression.

Availability

ULN2075B is available at Aetrix Electronics and suitable for industrial relay drivers, DC solenoid control, LED array drivers, and stepper motor phase switches requiring stable component supply and long-term industrial availability.

Supply support for ULN2075B 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, designing and manufacturing analog, digital, and mixed-signal ICs for automotive, industrial, and consumer markets.

The ULN2075B belongs to ST's high-voltage Darlington driver family, engineered specifically for robust logic-to-load interfacing in industrial control systems where emitter isolation and external diode flexibility are critical.

FAQ

Does ULN2075B include built-in flyback diodes?

No. Unlike ULN2065B, ULN2067B, and ULN2069B, the ULN2075B omits internal clamp diodes. Its isolated emitter pins require external diodes (e.g., 1N4007 or faster types) placed between each OUT and E pin for inductive load protection - enabling optimized diode selection per application.

What is the purpose of the isolated emitter pins on ULN2075B?

The four dedicated emitter pins (9, 11, 13, 15) enable emitter-follower operation, per-channel current sensing via external shunts, and independent flyback diode routing. This architecture avoids shared-emitter crosstalk and supports non-ground-referenced load configurations not possible with common-emitter Darlington arrays.

Can ULN2075B be used with 3.3 V logic inputs?

Yes. With its 350 Ω input resistors and VI(ON) ≤ 2.5 V at IC = 1 A, the ULN2075B reliably turns on from 3.3 V logic. Measured II(ON) is 1.4–3.3 mA at VI = 2.4–3.75 V, ensuring sufficient base drive while maintaining noise margin in mixed-voltage systems.

How does thermal performance compare between ULN2075B and ULN2065B?

Both share identical PowerDIP-16 packaging and 4.3 W maximum power dissipation at 90 °C pin temperature. However, ULN2075B's lack of internal diodes reduces junction self-heating under switching conditions. Effective thermal design requires grounding all GND pins (10, 12, 14, 16) to ≥1 cm² copper pour per datasheet Figure 14.

ULN2075B Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: 16-PowerDIP (0.300", 7.62mm)

Packaging:: Tube

Product Status:: Obsolete

Transistor Type:: 4 NPN Darlington (Quad)

Current - Collector (Ic) (Max):: 1.75A

Voltage - Collector Emitter Breakdown (Max):: 80V

Vce Saturation (Max) @ Ib, Ic:: 1.5V @ 2.25mA, 1.5A

Current - Collector Cutoff (Max):: -

DC Current Gain (hFE) (Min) @ Ic, Vce:: -

Power - Max:: 1W

Frequency - Transition:: -

Operating Temperature:: -20°C ~ 85°C (TA)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: 16-PowerDIP (20x7.10)

ULN2075B FAQ

1.How can I place an order for ULN2075B through Aetrix?

Please submit a Request for Quotation (RFQ) for ULN2075B on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for ULN2075B reliable?

The price and inventory of ULN2075B are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ULN2075B is usually 5 days.

3.What payment methods are accepted for ULN2075B?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ULN2075B transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for ULN2075B?

ULN2075B orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your ULN2075B order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for ULN2075B?

For technical support, including ULN2075B datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ULN2075B requirements.

6.How does Aetrix verify that ULN2075B is sourced from the original manufacturer or authorized distributors?

All ULN2075B products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that ULN2075B meets industry standards.

7.What is the process for return or replacement of ULN2075B?

All ULN2075B units undergo pre-shipment inspection (PSI). If there is an issue with ULN2075B, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The ULN2075B part is unused and in its original packaging.

Return procedure for ULN2075B:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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