ULN2066B STMicroelectronics Integrated Circuit (Dual-In-Line Packages) In Stock
STMicroelectronics ULN2066B is a quad Darlington transistor array in a 16-pin DIP package with 4 high-current NPN channels, each rated 1.75 A collector current and 35 V collector-emitter voltage, with built-in clamp diodes and base resistors. Logic-level compatible inputs simplify direct MCU drive. Available from stock with worldwide shipping.
- Manufacturer
- STMicroelectronics
- Package
- Dual-In-Line Packages
- Pin Count
- 16
- Lifecycle
- OBSOLETE
- Datasheet
- ULN2066B Datasheet PDF
- Category
- Integrated Circuit
- Price
- From $3.4219(MOQ 1000)
- RoHS
- Compliant
- Lead Time
- 3–7 business days
- Shipping
- DHL Express · Worldwide
What are the key features of ULN2066B?
- 4 independent Darlington NPN transistor channels each capable of 1.75 A collector current and 35 V VCE for driving relays, solenoids, and stepper motor windings directly
- Built-in flyback clamp diodes on every output channel protect against inductive load transients without external Schottky diodes
- Logic-level compatible inputs with integrated base series resistors allow direct connection from 3.3 V or 5 V MCU GPIO without external current-limiting resistors
- 16-pin DIP-16 package (R-PDIP-T16) enables through-hole breadboard prototyping and socketed field replacement in industrial control systems
What is ULN2066B used for?
The ULN2066B is used in stepper motor driver boards, relay driver modules, and solenoid valve controllers where a microcontroller's GPIO outputs must switch inductive loads up to 1.75 A at voltages up to 35 V. Its four Darlington channels with integrated flyback diodes simplify driving four-phase unipolar stepper motors directly from a single IC without discrete transistors or protection diodes. It is also popular in LED matrix drivers and lamp dimmer circuits that require moderate current sinking from a logic-level control signal.
What are the specifications of ULN2066B?
| YTEOL | 0 |
| Additional Feature | LOGIC LEVEL COMPATIBLE |
| Collector Current-Max (IC) | 1.75A |
| Collector-Emitter Voltage-Max | 35V |
| Configuration | 4 BANKS, DARLINGTON WITH BUILT-IN DIODE AND RESISTOR |
| JESD-30 Code | R-PDIP-T16 |
| JESD-609 Code | e3 |
| Number of Elements | 4 |
| Package Body Material | PLASTIC/EPOXY |
| Package Shape | RECTANGULAR |
| Package Style | IN-LINE |
| Peak Reflow Temperature (Cel) | NOT SPECIFIED |
| Polarity/Channel Type | NPN |
| Qualification Status | Not Qualified |
| Surface Mount | NO |
| Terminal Finish | Tin (Sn) |
| Terminal Form | THROUGH-HOLE |
| Terminal Position | DUAL |
| Time@Peak Reflow Temperature-Max (s) | NOT SPECIFIED |
| Transistor Application | SWITCHING |
| Transistor Element Material | SILICON |
| VCEsat-Max | 1.4V |
| Package | Dual-In-Line Packages |
Compliance & Regulatory
| RoHS Status | Compliant |
| Lead-Free | Yes (Pb-Free) |
| ECCN | EAR99 |
| Country of Origin | Malaysia |
Where can I find the ULN2066B datasheet?
ULN2066B Datasheet DownloadOfficial datasheet from STMicroelectronics
What are equivalent replacements for ULN2066B?
No known alternates. Submit an RFQ and our team can suggest alternatives.
Frequently Asked Questions
What are the maximum collector current and collector-emitter voltage ratings for each channel of the ULN2066B?
Each of the 4 Darlington channels in the ULN2066B is rated for a maximum collector current of 1.75 A and a collector-emitter voltage of 35 V. These ratings make each channel capable of directly driving a 12 V relay coil, a 24 V solenoid, or a unipolar stepper motor winding without external power transistors.
How do the built-in clamp diodes in the ULN2066B protect the circuit when driving inductive loads?
When an inductive load such as a relay or motor coil is switched off, the collapsing magnetic field generates a voltage spike that can exceed 35 V and destroy unprotected transistors. The ULN2066B's internal flyback clamp diodes connect from each collector to a common COM pin tied to the load supply, clamping the transient to the supply voltage plus one diode drop and protecting both the Darlington stages and any upstream MCU pins.
Can the ULN2066B be driven directly from a 3.3 V microcontroller GPIO without external components?
Yes. The ULN2066B is specified as logic-level compatible with integrated base resistors on each input, making it directly drivable from 3.3 V or 5 V CMOS/TTL GPIO outputs. The device requires an input voltage of approximately 1 V to saturate the first Darlington stage, so a standard 3.3 V logic HIGH reliably switches the output without any external series resistors or buffers.
How many stepper motor phases can one ULN2066B drive, and what configuration is supported?
The ULN2066B provides 4 independent Darlington channels, exactly matching the 4 phase windings of a standard unipolar stepper motor. Each channel handles up to 1.75 A, covering most NEMA 17 and NEMA 23 unipolar motors whose phase currents typically range from 0.5 A to 1.5 A per winding at 12 V to 24 V supply.
When is the ULN2066B preferred over the more common ULN2003A for a relay driver application?
The ULN2003A is rated at 500 mA per channel, which is sufficient for small signal relays but inadequate for power relays with coil currents above 500 mA. The ULN2066B with 1.75 A per channel is the correct choice when driving industrial-grade relays with 12 V or 24 V coils drawing 0.8 A to 1.5 A, or when four high-current solenoid valves must be controlled from a single 16-pin DIP footprint.
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Why Buy from FindMyChip
About STMicroelectronics
STMicroelectronics is a global semiconductor leader serving customers across the spectrum of electronics applications. ST's products are found in a wide range of applications including automotive, industrial, personal electronics, and communications.
| Qty. | Unit Price | Ext. Price |
|---|---|---|
| 1000+ | $3.4219 | $3421.88 |
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