ULQ2801A STMicroelectronics Integrated Circuit (Dual-In-Line Packages) In Stock
Octal NPN Darlington transistor array with open-collector outputs, rated at 50 V and 500 mA per channel, in an 18-pin DIP package with built-in flyback diodes. From $0.80 in stock with worldwide shipping.
- Manufacturer
- STMicroelectronics
- Package
- Dual-In-Line Packages
- Pin Count
- 18
- Lifecycle
- ACTIVE
- Datasheet
- ULQ2801A Datasheet PDF
- Category
- Integrated Circuit
- Price
- From $2.1984(MOQ 500)
- Temp Range
- -40.0°C to 85.0°C
- RoHS
- Compliant
- Lead Time
- 3–7 business days
- Shipping
- DHL Express · Worldwide
What are the key features of ULQ2801A?
- 8-channel Darlington NPN array with 500 mA per channel and 50 V output voltage for driving relays, solenoids, and stepper motors
- Integrated transient suppression diodes on each output channel protecting against inductive load flyback voltages up to 50 V
- Open-collector outputs with high current gain allowing direct interface between 3.3 V/5 V logic and high-power peripheral loads
What is ULQ2801A used for?
The ULQ2801A is used in industrial automation systems to drive 8 relay coils or solenoid actuators simultaneously from a single IC, replacing 8 discrete transistor drive circuits. It is commonly used in PLC output modules, stepper motor controllers, and printer head drivers where microcontroller GPIO pins at 3.3 V or 5 V must switch inductive loads at 12 V to 48 V. The built-in flyback diodes eliminate the need for external protection diodes, simplifying PCB design and reducing component count.
What are the specifications of ULQ2801A?
| Factory Lead Time | 10Weeks |
| YTEOL | 6 |
| Additional Feature | LENGTH IS MAX VALUE |
| Built-in Protections | TRANSIENT |
| Driver Number of Bits | 8 |
| Interface IC Type | BUFFER OR INVERTER BASED PERIPHERAL DRIVER |
| JESD-30 Code | R-PDIP-T18 |
| Number of Functions | 1 |
| Output Characteristics | OPEN-COLLECTOR |
| Output Current Flow Direction | SINK |
| Package Body Material | PLASTIC/EPOXY |
| Package Equivalence Code | DIP18,.3 |
| Package Shape | RECTANGULAR |
| Package Style | IN-LINE |
| Surface Mount | NO |
| Terminal Form | THROUGH-HOLE |
| Terminal Pitch | 2.54mm |
| Terminal Position | DUAL |
| Turn-off Time | 1 µs |
| Turn-on Time | 1 µs |
| Package | Dual-In-Line Packages |
Compliance & Regulatory
| RoHS Status | Compliant |
| Lead-Free | Yes (Pb-Free) |
| ECCN | EAR99 |
| HTS Code | 8542.39.00.60 |
| Country of Origin | Mainland China, Malaysia |
Where can I find the ULQ2801A datasheet?
ULQ2801A Datasheet DownloadOfficial datasheet from STMicroelectronics
What are equivalent replacements for ULQ2801A?
No known alternates. Submit an RFQ and our team can suggest alternatives.
Frequently Asked Questions
What is the maximum output voltage and per-channel current rating of the ULQ2801A Darlington array?
Each of the 8 channels in the ULQ2801A supports a maximum collector-emitter voltage of 50 V and a continuous output current of 500 mA. Total package dissipation limits simultaneous operation of all 8 channels; at 500 mA per channel with 2 V saturation, the total power dissipation is 8 W, requiring a heatsink or forced-air cooling in high-duty-cycle applications.
How do the built-in flyback diodes in ULQ2801A protect relay and solenoid driver circuits?
When an inductive load such as a relay coil is de-energized, the collapsing magnetic field generates a flyback voltage spike that can exceed 100 V in unprotected circuits. The ULQ2801A's internal flyback diodes clamp this spike to the supply voltage plus 0.7 V, limiting peak collector voltage to a safe level below the 50 V rating and preventing transistor breakdown without any external protection components.
Can ULQ2801A directly interface CMOS 3.3 V logic to a 24 V relay coil, and what is the circuit configuration?
The ULQ2801A can interface 3.3 V CMOS logic to a 24 V relay coil directly. The input threshold is compatible with 3.3 V CMOS logic levels, and the open-collector output sinks up to 500 mA from the 24 V relay coil through the collector terminal. The COM pin connects to the 24 V supply through the relay coil flyback diode path, completing the protection circuit without external components.
How does ULQ2801A compare to ULN2803A, and when should a designer choose one over the other?
The ULQ2801A and ULN2803A are both 8-channel Darlington arrays rated at 50 V and 500 mA per channel, but they differ in input sensitivity. The ULQ2801A is optimized for CMOS inputs with lower input current requirements below 25 µA at 3.3 V, while the ULN2803A includes 2.7 kilohm input resistors suited for 5 V TTL logic. Choose ULQ2801A for 3.3 V microcontroller designs to minimize GPIO loading; use ULN2803A for legacy 5 V TTL systems.
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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 |
|---|---|---|
| 500+ | $2.4608 | $1230.41 |
| 1000+ | $2.4000 | $2400.00 |
| 2000+ | $2.2500 | $4500.00 |
| 4000+ | $2.2213 | $8885.20 |
| 8000+ | $2.2098 | $17678.80 |
| 16000+ | $2.1984 | $35174.40 |
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