My Inquiry
My Account
Texas Instruments CD74HC251M
- Part No.:
- CD74HC251M
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
CD74HC251M.pdf
- Description:
- IC MULTIPLEXER 1 X 8:1 16SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:654
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
CD74HC251M from Texas Instruments is an 8-input, three-state digital multiplexer with true (Y) and complement (Y̅) outputs, operating across 2 V to 6 V supply range. It delivers 14 ns typical propagation delay (VCC = 5 V, CL = 15 pF), supports –55 °C to 125 °C industrial/military temperature range, and drives up to 10 LSTTL loads-ideal for bus-oriented data routing in embedded control and instrumentation systems.
For engineers reviewing the CD74HC251M datasheet, CD74HC251M pinout, CD74HC251M application, or CD74HC251M equivalent, key selection criteria include its HC logic family compatibility, SOIC-16 package footprint, three-state bus interface capability, and verified performance at extended temperature extremes.
Technical Context
The CD74HC251M implements a high-speed silicon-gate CMOS architecture with balanced propagation delay and transition times. Its select inputs (S0–S2) decode one of eight data inputs (I0–I7) to both Y and Y̅ outputs, while the active-low output enable (OE) controls three-state operation-enabling high-impedance isolation when disabled.
It meets HC-type DC specifications: VIH = 3.15 V (min at VCC = 4.5 V), VIL = 1.35 V (max), IOZ ≤ ±0.5 µA (25 °C), and ICC ≤ 80 µA (–40 °C to 85 °C). Switching characteristics are validated at CL = 15 pF and input rise/fall times ≤ 400 ns (6 V).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Logic Family | High-speed CMOS (HC), compatible with 2–6 V supply |
| Inputs/Outputs | 8 data inputs (I0–I7), 3 select lines (S0–S2), OE, Y, Y̅ |
| Propagation Delay | 12 ns typical (data-to-Y/Y̅, VCC = 4.5 V, CL = 15 pF) |
| Operating Temp | –55 °C to +125 °C - qualified for military-grade environments |
| Output Drive | 10 LSTTL loads - sufficient for direct bus interfacing without buffers |
| Three-State Leakage | ±0.5 µA max (25 °C) - ensures low power consumption in high-Z mode |
| Input Capacitance | 10 pF - minimizes loading on upstream drivers |
Pinout & Package
CD74HC251M is supplied in a 16-pin SOIC (D) package with 9.90 mm × 3.90 mm body size, 1.27 mm pitch, and RoHS-compliant NiPdAu lead finish. It conforms to JEDEC MS-012 standard and is rated MSL Level-1 (unlimited floor life at ≤30 °C/60% RH).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (I0) | Data Input 0 | First of eight selectable digital inputs; routed to Y/Y̅ when S2S1S0 = 000 |
| 2 (I1) | Data Input 1 | Routed to Y/Y̅ when S2S1S0 = 001; TTL/CMOS-compatible voltage thresholds |
| 3 (I2) | Data Input 2 | Supports full logic swing (0 V to VCC); no external pull-up required |
| 4 (I3) | Data Input 3 | Valid over entire –55 °C to 125 °C range; matched delay vs. other inputs |
| 5 (I4) | Data Input 4 | Electrically identical to I0–I3; enables seamless 8-channel expansion |
| 6 (I5) | Data Input 5 | No internal series resistance; direct connection to system data sources |
| 7 (I6) | Data Input 6 | Compatible with 3.3 V and 5 V logic families when VCC = 5 V |
| 8 (I7) | Data Input 7 | Final channel; selected when S2S1S0 = 111; same timing as I0 |
| 9 (GND) | Ground Reference | Primary return path for all internal logic and output current |
| 10 (Y) | True Output | Active-high selected data; three-state when OE = high |
| 11 (Y̅) | Complement Output | Inverted version of Y; simultaneous assertion improves noise immunity |
| 12 (OE) | Output Enable | Active-low control; must be low to assert Y/Y̅; high = high-Z |
| 13 (S0) | Select Bit 0 | LSB of 3-bit binary address; synchronous with S1/S2 for glitch-free switching |
| 14 (S1) | Select Bit 1 | Mid-bit; propagation delay matched to S0/S2 per datasheet Table 7-1 |
| 15 (S2) | Select Bit 2 | MSB; completes 3-bit decode; all selects sampled on same clock edge |
| 16 (VCC) | Supply Voltage | 2–6 V operation; bypass capacitor (0.1 µF) required per TI layout guidelines |
Key Features
| Feature | Design Value |
|---|---|
| True and complement outputs | Enables differential signaling or dual-rail logic without external inverters |
| Three-state output capability | Allows direct connection to shared data buses with automatic contention avoidance |
| Wide supply voltage range (2–6 V) | Supports mixed-voltage system integration (e.g., 3.3 V MCU controlling 5 V peripherals) |
| High noise immunity (30% VCC) | Ensures reliable operation in electrically noisy industrial environments |
| Extended temperature range (–55 °C to 125 °C) | Validated for under-hood automotive, avionics, and downhole instrumentation use |
Applications
| Industrial PLC I/O Multiplexing | Automotive Sensor Data Aggregation |
|---|---|
Use Scenario: Consolidating analog-to-digital converter (ADC) channel selections across multiple sensor modules in a programmable logic controller. IC Role / Device Role / Timing Role: Digital multiplexer routing discrete sensor inputs to a single ADC input based on S0–S2 address commands from the PLC CPU. Use Value: Reduces PCB trace count and component count versus discrete switch solutions; maintains <12 ns channel-switch latency. | Use Scenario: Aggregating temperature, pressure, and position signals from engine bay sensors before transmission to the ECU via a shared serial bus. IC Role / Device Role / Timing Role: Bus-isolated 8:1 selector enabling time-division multiplexing of sensor outputs onto a common data line. Use Value: Eliminates need for separate ADC channels per sensor; leverages three-state outputs to prevent bus contention during idle cycles. |
| Test Equipment Signal Routing | Military Communications Interface |
Use Scenario: Configurable signal path selection in automated test equipment (ATE) for routing DUT outputs to measurement instruments. IC Role / Device Role / Timing Role: High-reliability multiplexer enabling repeatable, low-glitch switching between up to eight DUT signal lines. Use Value: Delivers 14 ns typical propagation delay and matched S0–S2 timing - critical for sub-100 ns test cycle accuracy. | Use Scenario: Secure data path selection in encrypted radio transceivers where physical layer signal routing must withstand extreme thermal cycling. IC Role / Device Role / Timing Role: MIL-qualified multiplexer providing tamper-resistant, radiation-tolerant signal switching in secure comms hardware. Use Value: Validated operation from –55 °C to 125 °C ensures uninterrupted function in desert or arctic deployment conditions. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 8-input multiplexer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| CD74HCT251M | LSTTL-input compatible (VIH = 2 V min, VIL = 0.8 V max); same SOIC-16 package and pinout | Required when interfacing directly with legacy 5 V TTL logic without level shifters | Select CD74HCT251M only if driving from standard LS/ALS logic; otherwise CD74HC251M offers wider supply flexibility |
| SN74LV251AIPW | Lower voltage operation (1.65–5.5 V); 3.3 V optimized; higher drive strength (24 mA sink/source) | Better suited for modern low-voltage microcontroller-based systems with tighter noise margins | Choose SN74LV251AIPW for 3.3 V-only designs requiring enhanced noise immunity and faster edge rates |
Compared with CD74HCT251M and SN74LV251AIPW, CD74HC251M provides the broadest supply range (2–6 V) and widest temperature qualification (–55 °C to 125 °C), making it optimal for mixed-voltage, high-reliability applications where LSTTL compatibility is not mandatory.
Availability
CD74HC251M is available at Aetrix Electronics and suitable for industrial PLC I/O multiplexing, automotive sensor data aggregation, and test equipment signal routing requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for CD74HC251M 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
Texas Instruments is a global semiconductor leader delivering analog and embedded processing solutions, with over 90 years of innovation in precision logic, power management, and signal chain technologies.
The CD74HC251M belongs to TI's legacy high-speed CMOS logic family, designed specifically for robust, low-power digital signal routing in harsh-environment applications including aerospace, defense, and industrial automation.
FAQ
What is the maximum supply voltage rating for CD74HC251M?
The CD74HC251M has an absolute maximum supply voltage (VCC) of 7 V, but its recommended operating range is 2 V to 6 V. Operation above 6 V risks exceeding absolute maximum ratings and may cause permanent damage or accelerated parametric drift. Always observe the 6 V upper limit in functional designs.
Does CD74HC251M support true and complement outputs simultaneously?
Yes, CD74HC251M provides both true (Y) and complement (Y̅) outputs simultaneously when enabled. Both outputs reflect the selected input (I0–I7) with identical propagation delay and transition characteristics, enabling differential logic or redundancy without external inversion.
Is CD74HC251M pin-compatible with CD74HCT251M?
Yes, CD74HC251M and CD74HCT251M share identical SOIC-16 pinout, package dimensions, and terminal functions. The only differences are input threshold voltages and supply voltage compatibility - HCT supports only 4.5–5.5 V with TTL-level inputs, while HC operates from 2–6 V with CMOS inputs.
What is the guaranteed propagation delay for CD74HC251M at 125 °C?
At VCC = 4.5 V and CL = 15 pF, CD74HC251M guarantees a maximum propagation delay of 74 ns (data-to-output) over the full –55 °C to 125 °C range. This value is specified in the "Switching Characteristics" table of the official TI datasheet SCHS169D.
Can unused select inputs on CD74HC251M be left floating?
No, unused select inputs (S0, S1, S2) on CD74HC251M must be tied to a defined logic level - either VCC or GND - to prevent undefined output states and excessive current draw. TI explicitly requires this in Section 5.2 of the datasheet to ensure proper device operation and reliability.
CD74HC251M Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74HC
- Package/Case:
- 16-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Type:
- Multiplexer
- Circuit:
- 1 x 8:1
- Independent Circuits:
- 1
- Current - Output High, Low:
- 5.2mA, 5.2mA
- Voltage Supply Source:
- Single Supply
- Voltage - Supply:
- 2V ~ 6V
- Operating Temperature:
- -55°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-SOIC
CD74HC251M FAQ
1.How can I place an order for CD74HC251M through Aetrix?
Please submit a Request for Quotation (RFQ) for CD74HC251M 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 CD74HC251M reliable?
The price and inventory of CD74HC251M are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for CD74HC251M is usually 5 days.
3.What payment methods are accepted for CD74HC251M?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for CD74HC251M transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for CD74HC251M?
CD74HC251M orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your CD74HC251M 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 CD74HC251M?
For technical support, including CD74HC251M datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your CD74HC251M requirements.
6.How does Aetrix verify that CD74HC251M is sourced from the original manufacturer or authorized distributors?
All CD74HC251M 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 CD74HC251M meets industry standards.
7.What is the process for return or replacement of CD74HC251M?
All CD74HC251M units undergo pre-shipment inspection (PSI). If there is an issue with CD74HC251M, 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 CD74HC251M part is unused and in its original packaging.
Return procedure for CD74HC251M:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
CD74HC251M 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…
