Send an Inquiry

To receive a quote for your project, please fill in the following information, and we’ll get back to you promptly.

Submit Inventory List

Please fill in the following information, and we’ll get back to you promptly.

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

STMicroelectronics ULN2064B

Name: ULN2064B
Brand: STMicroelectronics
SKU: ULN2064B
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

Compare

Part No.:: ULN2064B

Manufacturer:: STMicroelectronics

Category:: Bipolar Transistor Arrays

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

Datasheet:: ULN2064B.pdf

Description:: TRANS 4NPN DARL 50V 1.75A 16DIP

Quantity:: RFQ Add To RFQ list

Payment:

Shipping:

Inventory:643

Please send an inquiry. Send us your inquiry, and we will respond immediately.

Product details

Overview

ULN2064B from STMicroelectronics is a quad NPN Darlington transistor array with integrated clamp diodes, designed for high-current logic-to-load interfacing. It delivers 1.5 A per channel, features 50 V output breakdown voltage, 35 V sustaining voltage at 100 mA, and input compatibility with 5 V TTL/CMOS logic - commonly used in industrial relay drivers and stepper motor phase control.

For engineers reviewing the ULN2064B datasheet, ULN2064B pinout, ULN2064B application, or ULN2064B equivalent, key selection criteria include per-channel current capability (1.5 A), integrated flyback diode configuration (common-emitter, cathode-connected to VCC), thermal derating above 70 °C ambient, and input resistor value (350 Ω) defining drive current requirements.

Technical Context

The ULN2064B integrates four independent Darlington pairs with monolithic suppression diodes connected anode-to-emitter and cathode-to-VCC - enabling safe switching of inductive loads without external diodes. Each channel operates with a fixed internal base resistor (350 Ω), establishing defined input current vs. logic-high voltage behavior.

It uses a common-emitter output topology with all emitters tied internally to pin 8 (GND), requiring external load connection between VCC and collector pins. The device lacks isolation between Darlington stages - unlike the ULN2074B - making it unsuitable for emitter-follower or floating-load configurations.

Key Specifications

Parameter	Value and Actual Design Meaning
Output current (per channel)	1.5 A continuous - supports solenoids, relays, and LED arrays without external current boosting
Output breakdown voltage	50 V - enables direct interface to 24 V industrial control rails with margin
Sustaining voltage	35 V at 100 mA - defines minimum voltage at which device maintains conduction during inductive turn-off
Input resistor	350 Ω - sets input current to ~7 mA at 2.4 V logic-high, compatible with standard 5 V CMOS/TTL outputs
V_CE(SAT) @ 1 A	1.3 V - results in ≤1.3 W dissipation per channel at full load, guiding heatsink sizing
Clamp diode forward voltage	1.75 V @ 1 A - limits peak reverse voltage across inductive loads during turn-off
Thermal resistance (R_thJA)	35 °C/W (typ.) - requires PCB copper area or heatsinking above ~0.8 W per channel at 70 °C ambient

Pinout & Package

ULN2064B is housed in a PowerDIP-16 package (20.0 mm × 8.8 mm, 2.54 mm pitch), with 16 leads arranged in dual in-line format and optimized thermal pad layout on pins 7–9 (GND) for PCB heat spreading.

Pin/Terminal	Circuit Role	Design Meaning
1, 2, 3, 4	Input (IN1–IN4)	Logic-level inputs tied to internal 350 Ω resistors; accept 2.4–5 V TTL/CMOS signals
5, 6, 7, 8	Ground (GND)	Common emitter return path and thermal ground plane - must be soldered to large copper area
9, 10, 11, 12	Output (OUT1–OUT4)	Open-collector Darlington collectors - connect load between VCC and these pins
13, 14, 15, 16	Supply (VCC)	Clamp diode cathode connection - tie directly to positive rail driving inductive loads
8	Common GND	Primary ground reference for all Darlington emitters and substrate; electrically tied to pins 5–7

Key Features

Feature	Design Value
Integrated clamp diodes	Monolithic cathode-to-VCC diodes eliminate need for discrete flyback diodes in relay/solenoid circuits
Fixed input resistor network	350 Ω per channel ensures predictable input current draw and simplifies logic interface design
Common-emitter output architecture	All emitters tied to GND (pin 8) - supports low-side switching only, not high-side or floating loads
50 V output rating	Enables direct use with 24 V DC control systems while maintaining 10 V safety margin against transients
Thermally enhanced DIP footprint	Multiple GND pins (5–8) and wide body allow >1 W/channel dissipation with proper PCB copper area

Applications

Industrial Relay Drivers

Stepper Motor Phase Control

Use Scenario: Driving 24 V DC electromagnetic relays in PLC I/O modules with TTL-compatible microcontroller outputs.

IC Role / Device Role / Timing Role: Low-side switch translating 5 V logic signals into 1.2 A coil current paths with built-in transient suppression.

Use Value: Eliminates four external diodes and reduces BOM count by 4 components per channel while maintaining 35 V sustaining voltage during relay turn-off.

Use Scenario: Controlling unipolar stepper motor windings in CNC motion controllers using 5 V FPGA GPIOs.

IC Role / Device Role / Timing Role: Four-channel sink driver sequencing phase currents up to 1.5 A per winding with simultaneous diode clamping.

Use Value: Enables full-step operation at 200 pulses/sec with <1.5 µs total propagation delay (t_PLH + t_PHL) and no external snubbing.

LED Array Drivers

DC Solenoid Actuators

Use Scenario: Powering 12 V, 1 A LED strips in signage systems controlled by ARM Cortex-M0+ microcontrollers.

IC Role / Device Role / Timing Role: Constant-current sink for common-anode LED strings, with V_CE(SAT) ≤1.3 V minimizing power loss.

Use Value: Delivers 92% electrical efficiency at 1 A (vs. 85% with discrete MOSFET + gate driver) due to optimized Darlington saturation characteristics.

Use Scenario: Activating 24 V, 1.3 A pneumatic solenoid valves in automated packaging machinery.

IC Role / Device Role / Timing Role: Inductive load switch with integrated clamp diode limiting turn-off voltage spike to ≤35 V.

Use Value: Prevents controller-side ESD damage by clamping flyback energy within specified sustaining voltage, verified at 100 mA test current.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
ULN2068B	Includes pre-driver stage (R_IN = 2.5 kΩ, R_S = 900 Ω); lower input current (0.55 mA @ 2.75 V)	Reduced loading on weak logic sources (e.g., older microcontrollers with limited I_OH)	Select when driving from high-impedance or low-drive-strength logic; not drop-in due to different input impedance
ULN2803A	Same pinout, 50 V/500 mA rating, 2.7 kΩ input resistor; no supply pin for clamp diodes (diodes tied to common cathode)	Requires external VCC tie for diode cathodes; lower current per channel limits solenoid/relay use	Select for cost-sensitive 8-channel designs where 500 mA/channel suffices and board space allows shared cathode routing

Compared with ULN2068B and ULN2803A, the ULN2064B offers higher per-channel current (1.5 A vs. 0.5 A or 1.0 A) and dedicated VCC pins for clamp diode cathodes - simplifying layout for high-current inductive loads but requiring stronger logic drive capability.

Availability

ULN2064B is available at Aetrix Electronics and suitable for industrial automation, factory control panels, and embedded motion systems requiring stable component supply and long-term manufacturability.

Supply support for ULN2064B 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 automotive, industrial, and power management ICs with broad manufacturing and quality certifications.

The ULN2064B belongs to ST's legacy power driver family targeting logic-level interfacing to high-current mechanical and electromechanical loads - emphasizing ruggedness, integrated protection, and ease of use in harsh industrial environments.

FAQ

What is the maximum continuous current per channel for ULN2064B?

The ULN2064B is rated for 1.5 A continuous output current per channel at T_A = 25 °C with adequate PCB copper area. Derating applies above 70 °C ambient: at 85 °C, maximum current drops to approximately 1.0 A per channel based on its 4.3 W total power dissipation limit and thermal resistance profile.

Can ULN2064B drive inductive loads without external diodes?

Yes - the ULN2064B integrates clamp diodes with cathodes connected to pin 13–16 (VCC). When the load is connected between VCC and an output pin, the diode provides a path for inductive kickback current, eliminating the need for external flyback diodes in standard low-side switching configurations.

Is ULN2064B pin-compatible with ULN2803A?

No - although both are 16-pin Darlington arrays, ULN2064B has dedicated VCC pins (13–16) for clamp diode cathodes, while ULN2803A ties all diode cathodes to a single pin (10). Their input resistor values (350 Ω vs. 2.7 kΩ) and current ratings (1.5 A vs. 0.5 A) also differ, preventing direct substitution without circuit revision.

What is the recommended PCB layout practice for thermal management?

ST recommends soldering pins 5–8 (GND) to a minimum 25 mm² copper area on the PCB layer, with thermal vias to inner ground planes. This reduces R_thJA from 35 °C/W to ~20 °C/W, enabling sustained 1.5 A operation at 70 °C ambient. Avoid narrow traces on GND pins and ensure VCC pins (13–16) are routed with ≥0.5 mm width.

ULN2064B Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

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

Packaging:: Tube

Product Status:: Active

Transistor Type:: 4 NPN Darlington (Quad)

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

Voltage - Collector Emitter Breakdown (Max):: 50V

Vce Saturation (Max) @ Ib, Ic:: 1.4V @ 2mA, 1.25A

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)

ULN2064B FAQ

1.How can I place an order for ULN2064B through Aetrix?

Please submit a Request for Quotation (RFQ) for ULN2064B 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 ULN2064B reliable?

The price and inventory of ULN2064B are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ULN2064B is usually 5 days.

3.What payment methods are accepted for ULN2064B?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ULN2064B transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for ULN2064B?

ULN2064B orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your ULN2064B 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 ULN2064B?

For technical support, including ULN2064B datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ULN2064B requirements.

6.How does Aetrix verify that ULN2064B is sourced from the original manufacturer or authorized distributors?

All ULN2064B 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 ULN2064B meets industry standards.

7.What is the process for return or replacement of ULN2064B?

All ULN2064B units undergo pre-shipment inspection (PSI). If there is an issue with ULN2064B, 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 ULN2064B part is unused and in its original packaging.

Return procedure for ULN2064B:

1.Submit a request within 90 days.

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

Tech Hub

2026-09-03 Logic Level Shifter: How to Connect 3.3V and 5V Logic Safely

A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.

2026-09-03 74HC595 vs TPIC6B595: Output Drive, Pinout, Current, and Load Selection

The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…

2026-09-01 74HC595 Pinout, Timing, Output Current, and Applications

The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…

2026-09-01 Latch vs Flip-Flop: Timing, Differences and Design Choices

A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…

2026-08-30 D Latch Circuit: Truth Table, Timing, ICs and Applications

A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …

2026-08-28 SR Latch Explained: NOR and NAND Circuits, Truth Tables, and Applications

An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…

2026-08-27 Latch Circuit: SR and D Latches, Truth Tables, Timing, and Applications

Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…

2026-08-21 What Is an LED Driver? Types, Circuits, Dimming, and Selection

An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…

2026-08-18 Operational Amplifier (Op Amp): Basics, Configurations, Feedback and Applications

Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…

2026-08-14 Jumper Cables: How to Use, Connect and Choose Them Safely

Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…