My Inquiry
My Account
NXP Semiconductors 74HCT251DB,112
- Part No.:
- 74HCT251DB,112
- Manufacturer:
- NXP Semiconductors
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-SSOP (0.209", 5.30mm Width)
- Datasheet:
-
74HCT251DB,112.pdf
- Description:
- IC 8-INPUT MUX 3ST 16-SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,368
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
74HCT251DB,112 from NXP Semiconductors is an 8-input CMOS multiplexer with true and complement 3-state outputs, designed for digital signal routing in TTL-compatible systems. It features propagation delays as low as 22 ns (In→Y), operates at 4.5 V supply, supports select input control (S0–S2), and enables multiplexer expansion via high-impedance outputs - used in data selector circuits within industrial control logic and test equipment.
For engineers reviewing the 74HCT251DB,112 datasheet, 74HCT251DB,112 pinout, 74HCT251DB,112 application, or 74HCT251DB,112 equivalent, key selection criteria include 3-state output timing (tPZH/tPHZ ≤ 42 ns), HCT-level TTL input thresholds (VI = GND to 3 V), dual-output capability (Y and Y), and SO16 package compatibility with standard PCB footprints.
Technical Context
The 74HCT251DB,112 implements a single-pole, 8-position analog/digital switch controlled by three binary select lines (S0–S2), delivering routed data on both true (Y) and complement (Y) outputs. Its active-low output enable (OE) places both outputs in high-impedance state when asserted high, enabling parallel multiplexer cascading without external gating.
It belongs to the 74HCT family, ensuring direct interface with legacy LSTTL logic while maintaining CMOS power efficiency. Input thresholds match TTL levels (VIH = 2.0 V min, VIL = 0.8 V max at VCC = 4.5 V), and propagation delay symmetry between Y and Y paths is maintained across all input-to-output combinations.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Logic Family | 74HCT - TTL-compatible CMOS, ensures interoperability with 5 V LSTTL systems without level shifters |
| Supply Voltage | 4.5 V to 5.5 V - supports standard 5 V rail with ±10% tolerance; not rated for 3.3 V operation |
| Propagation Delay (In→Y) | 22 ns (min) to 53 ns (max) at VCC = 4.5 V, CL = 50 pF - defines worst-case data path latency in synchronous routing |
| 3-State Enable Time (OE→Y) | 13 ns (min) to 42 ns (max) - determines minimum interval before valid output after OE assertion |
| Input Capacitance | 3.5 pF - limits capacitive loading on driving gates and supports high-frequency bus termination |
| Output Drive | Standard CMOS drive (±4 mA at VCC = 4.5 V) - compatible with fan-out of 10 LSTTL loads |
| Operating Temperature | −40 °C to +125 °C - qualified for extended industrial and automotive under-hood environments |
Pinout & Package
74HCT251DB,112 is housed in a 16-pin SO (Small Outline) package with 1.27 mm pitch, JEDEC MS-012AC compliant, and surface-mount compatible. Pin 1 is marked by a bevelled corner or notch.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 15, 14, 13, 12, 4, 3, 2 | I0–I7 | Eight independent data inputs; selected one appears at Y/Y based on S0–S2 address |
| 5 | Y | True output - active when OE = LOW and reflects selected input logic state |
| 6 | Y | Complement output - inverted version of Y; both outputs simultaneously enabled or disabled |
| 7 | OE | Active-low 3-state enable - HIGH forces Y/Y into high-Z; essential for bus sharing |
| 8 | GND | Ground reference - must be low-impedance connection to minimize noise coupling |
| 9, 10, 11 | S0, S1, S2 | Binary select inputs - encode 0–7 to route corresponding I0–I7 to outputs |
| 16 | VCC | Positive supply - powers internal logic and output drivers; decoupling capacitor required |
Key Features
| Feature | Design Value |
|---|---|
| Dual true/complement outputs | Enables simultaneous access to signal and its inverse without external inverters - reduces component count in parity or differential bus designs |
| 3-state outputs with common OE | Allows multiple 74HCT251DB,112 devices to share a common data bus - critical for modular backplane or test fixture architectures |
| TTL-compatible input thresholds | Accepts standard 5 V TTL logic levels (VIH ≥ 2.0 V, VIL ≤ 0.8 V) - eliminates need for level translation when interfacing with legacy controllers |
| High noise immunity | CMOS input structure provides >400 mV noise margin at VCC = 4.5 V - improves reliability in electrically noisy industrial enclosures |
| Extended temperature range | Rated from −40 °C to +125 °C - suitable for under-dash automotive modules and factory-floor PLC I/O cards |
Applications
| Industrial PLC I/O Multiplexing | Automotive Diagnostic Bus Selector |
|---|---|
Use Scenario: A programmable logic controller routes sensor inputs from 8 analog-to-digital channels onto a shared serial data bus. IC Role / Device Role / Timing Role: 74HCT251DB,112 acts as a digitally controlled analog signal selector, synchronized to the PLC scan cycle via OE gating. Use Value: Reduces board space and wiring complexity by consolidating eight discrete signal paths into one bidirectional bus line. | Use Scenario: An OBD-II diagnostic tool selects between eight vehicle subsystem signals (ABS, airbag, engine, transmission, etc.) for real-time monitoring. IC Role / Device Role / Timing Role: 74HCT251DB,112 serves as a manual or microcontroller-driven channel selector, with OE used to isolate inactive subsystems during measurement. Use Value: Enables single-instrument multi-system diagnostics without hardware reconfiguration or relay switching. |
| Test Equipment Signal Routing | Digital Logic Training Board |
Use Scenario: Automated test equipment applies stimulus signals to one of eight DUT pins while monitoring response through a common acquisition channel. IC Role / Device Role / Timing Role: 74HCT251DB,112 functions as a precision timing-controlled multiplexer, where S0–S2 are driven by pattern generator outputs and OE is synchronized to sampling clock edges. Use Value: Achieves sub-50 ns channel switching repeatability, supporting high-speed functional testing of digital ICs. | Use Scenario: Educational lab board demonstrates combinational logic concepts using physical switches for S0–S2 and LEDs for Y/Y outputs. IC Role / Device Role / Timing Role: 74HCT251DB,112 provides hands-on verification of Boolean multiplexing equations and 3-state behavior under manual OE control. Use Value: Reinforces understanding of address decoding, bus contention avoidance, and complementary logic synthesis in entry-level digital electronics labs. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 8-input multiplexer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74HCT251N | DIP-16 package; identical AC/DC specs and pinout; higher parasitic inductance limits >20 MHz use | Breadboard and prototyping-friendly; unsuitable for high-density SMT layouts | Select when manual assembly, socket-based testing, or through-hole PCB design is required |
| 74HCT251PW,118 | TSSOP-16 package; same electrical specs; 4.4 mm width vs. SO16's 10 mm - 55% smaller footprint | Enables compact portable instrumentation and space-constrained automotive ECUs | Choose for volume SMT production where board area and thermal profile are critical |
Compared with SN74HCT251N and 74HCT251PW,118, the 74HCT251DB,112 offers optimal balance of thermal performance (SO package θJA ≈ 120 K/W), mechanical robustness, and compatibility with standard reflow profiles - making it preferred for industrial-grade automated assembly.
Availability
74HCT251DB,112 is available at Aetrix Electronics and suitable for industrial PLC I/O modules, automotive diagnostic tools, and automated test equipment requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.
Supply support for 74HCT251DB,112 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
NXP Semiconductors is a global semiconductor leader focused on secure connectivity solutions for automotive, industrial, and IoT applications, with roots in Philips' semiconductor division.
The 74HCT251DB,112 belongs to NXP's legacy 74HCT logic family, engineered for seamless integration into 5 V mixed-signal systems where TTL compatibility, low static power, and deterministic 3-state timing are essential.
FAQ
What is the maximum operating frequency supported by the 74HCT251DB,112?
The 74HCT251DB,112 does not specify a maximum clock or data rate in its datasheet. Its usable frequency depends on propagation delay (≤53 ns) and output transition time (≤22 ns). For reliable operation, input signal periods should exceed 100 ns - supporting data rates up to approximately 10 MHz in typical routing applications. System-level timing margins must account for board trace delays and load capacitance.
Does the 74HCT251DB,112 support 3.3 V logic inputs?
No, the 74HCT251DB,112 is not guaranteed to operate correctly with 3.3 V logic inputs. Its input voltage thresholds are optimized for TTL levels (VIH ≥ 2.0 V, VIL ≤ 0.8 V at VCC = 4.5 V), and the datasheet specifies VI = GND to 3 V only for HCT-family compatibility - not for 3.3 V system interfacing. Direct connection to 3.3 V drivers may cause undefined states or increased ICC.
Can Y and Y outputs be used independently in the 74HCT251DB,112?
No - Y and Y outputs in the 74HCT251DB,112 are functionally linked and always enabled or disabled together by the OE pin. Both outputs enter high-impedance state simultaneously when OE is HIGH, and both reflect the selected input (and its inverse) when OE is LOW. Independent control of Y and Y is not supported by the internal architecture.
What is the power dissipation capacitance (CPD) of the 74HCT251DB,112?
The 74HCT251DB,112 has a power dissipation capacitance (CPD) of 46 pF, as specified in the Quick Reference Data table. This value is used to calculate dynamic power consumption using PD = CPD × VCC² × fi + Σ(CL × VCC² × fo), where fi is input frequency and fo is output frequency - critical for thermal design in high-density logic assemblies.
Is the 74HCT251DB,112 RoHS compliant?
Yes, the 74HCT251DB,112 is RoHS compliant per EU Directive 2011/65/EU. NXP confirms lead-free terminations and halogen-free molding compound for this SO16 variant, with full compliance documented in the product's environmental compliance statement (document number QG-0000128 rev. E).
74HCT251DB,112 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- NXP Semiconductors
- Series:
- 74HCT
- Package/Case:
- 16-SSOP (0.209", 5.30mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Type:
- Multiplexer
- Circuit:
- 1 x 8:1
- Independent Circuits:
- 1
- Current - Output High, Low:
- 4mA, 4mA
- Voltage Supply Source:
- Single Supply
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-SSOP
74HCT251DB,112 FAQ
1.How can I place an order for 74HCT251DB,112 through Aetrix?
Please submit a Request for Quotation (RFQ) for 74HCT251DB,112 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 74HCT251DB,112 reliable?
The price and inventory of 74HCT251DB,112 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 74HCT251DB,112 is usually 5 days.
3.What payment methods are accepted for 74HCT251DB,112?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 74HCT251DB,112 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 74HCT251DB,112?
74HCT251DB,112 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 74HCT251DB,112 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 74HCT251DB,112?
For technical support, including 74HCT251DB,112 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 74HCT251DB,112 requirements.
6.How does Aetrix verify that 74HCT251DB,112 is sourced from the original manufacturer or authorized distributors?
All 74HCT251DB,112 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 74HCT251DB,112 meets industry standards.
7.What is the process for return or replacement of 74HCT251DB,112?
All 74HCT251DB,112 units undergo pre-shipment inspection (PSI). If there is an issue with 74HCT251DB,112, 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 74HCT251DB,112 part is unused and in its original packaging.
Return procedure for 74HCT251DB,112:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
74HCT251DB,112 Tags
-
SN74HC138DR
Texas Instruments
-
TC7SB3157CFU,LF(CT
Toshiba Semiconductor and Storage
-
74CBTLV3257PW,118
Nexperia USA Inc.
-
SN74CBTLV3257PWR
Texas Instruments
-
74CBTLV3257GUX
Nexperia USA Inc.
-
74HC154BQ,118
Nexperia USA Inc.
-
P3S0200GMX
NXP USA Inc.
-
SN74CB3Q3245PWR
Texas Instruments
-
SN74CB3Q3257RGYR
Texas Instruments
-
TCA9543APWR
Texas Instruments
-
TCA9546APWR
Texas Instruments
-
SN74HC138N
Texas Instruments
Tech Hub
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.
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…
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…
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…
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 …
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…
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…
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…
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…
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…
