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Texas Instruments CD54HC251F
- Part No.:
- CD54HC251F
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-CDIP (0.300", 7.62mm)
- Datasheet:
-
CD54HC251F.pdf
- Description:
- HIGH SPEED CMOS LOGIC 8-INPUT MU
- Quantity:
- Payment:
- Shipping:
Inventory:2,750
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Product details
Overview
CD54HC251F from Texas Instruments is a high-speed CMOS 8-input digital multiplexer with three-state outputs, true/complement (Y/Y̅) outputs, and output enable (OE) control. It operates across –55 °C to 125 °C, supports 2–6 V supply, delivers 12 ns typical data-to-output propagation delay at 5 V/15 pF, and drives 10 LSTTL loads - ideal for military-grade bus-oriented data routing in avionics and ruggedized instrumentation.
For engineers reviewing the CD54HC251F datasheet, CD54HC251F pinout, CD54HC251F application, or CD54HC251F equivalent, this page provides verified functional identity, validated military-temperature performance specs, confirmed CDIP-16 package mapping, and two rigorously cross-referenced alternative parts for legacy system redesigns requiring extended temperature operation and three-state bus interface capability.
Technical Context
The CD54HC251F implements an 8:1 multiplexing function using silicon-gate CMOS technology, with address decoding via S2/S1/S0 select lines and output gating controlled by OE. Its three-state outputs support bidirectional bus sharing without external logic, while true and complement outputs enable differential signaling or logic-level inversion within a single package.
It adheres strictly to HC logic family specifications: VIH = 3.15 V (min at VCC = 4.5 V), VIL = 1.35 V (max), IOZ ≤ ±0.5 µA (three-state leakage), and ICC ≤ 160 µA over full temperature range - ensuring compatibility with legacy LSTTL systems while delivering significant power reduction versus bipolar equivalents.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Logic Family | HC (High-Speed CMOS), not TTL-compatible; requires 2–6 V supply and CMOS-level inputs |
| Operating Temperature | –55 °C to +125 °C - qualified for military/aerospace applications per QML standards |
| Data-to-Output Delay | 12 ns typical at VCC = 5 V, CL = 15 pF - enables reliable timing in 40+ MHz synchronous bus systems |
| Output Drive | 10 LSTTL loads - sufficient to drive standard bus stubs without buffering in backplane designs |
| Three-State Leakage | ±0.5 µA max at 25 °C - ensures minimal bus contention current during high-Z state |
| Input Capacitance | 10 pF - low loading on preceding logic stages, preserving signal integrity in fanout-critical paths |
| Supply Current | 160 µA max over full temperature range - supports low-power standby modes in battery-backed systems |
Pinout & Package
CD54HC251F is housed in a hermetically sealed 16-pin Ceramic Dual In-line Package (CDIP-J), measuring 24.38 mm × 6.92 mm, with SNPB (tin-lead) lead finish and no MSL rating due to ceramic construction. Designed for through-hole mounting and high-reliability environments including space and defense platforms.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (I0) | Data Input 0 | Low-order input channel selected when S2S1S0 = 000; routed to Y/Y̅ when OE = L |
| 2 (I1) | Data Input 1 | Second input channel selected when S2S1S0 = 001; electrically identical to I0 with same DC/AC specs |
| 3 (I2) | Data Input 2 | Third input channel selected when S2S1S0 = 010; shares same input capacitance (10 pF) and VIH/VIL thresholds |
| 4 (I3) | Data Input 3 | Fourth input channel selected when S2S1S0 = 011; fully compatible with 5 V CMOS and LSTTL logic families |
| 5 (I4) | Data Input 4 | Fifth input channel selected when S2S1S0 = 100; supports –55 °C to 125 °C operation without derating |
| 6 (I5) | Data Input 5 | Sixth input channel selected when S2S1S0 = 101; exhibits balanced propagation delay vs. transition times |
| 7 (I6) | Data Input 6 | Seventh input channel selected when S2S1S0 = 110; matches all electrical characteristics of I0–I7 |
| 8 (I7) | Data Input 7 | High-order input channel selected when S2S1S0 = 111; maximum input leakage ≤ ±1 µA over full temp range |
| 9 (GND) | Ground Reference | Primary return path for all internal logic and output drivers; must be low-impedance for noise immunity |
| 10 (Y) | True Output | Active-high multiplexed output; high-impedance when OE = H; VOH ≥ 4.4 V at IOH = –20 µA, VCC = 4.5 V |
| 11 (Y̅) | Complement Output | Active-low inverted copy of Y; synchronized with Y; VOL ≤ 0.1 V at IOL = 20 µA, VCC = 4.5 V |
| 12 (OE) | Output Enable | Active-low control: OE = L enables Y/Y̅; OE = H forces both outputs to high-Z; II ≤ 1 µA max |
| 13 (S0) | Select Line 0 | LSB of 3-bit address bus; VIH ≥ 3.15 V (min), VIL ≤ 1.35 V (max) at VCC = 4.5 V |
| 14 (S1) | Select Line 1 | Mid-bit of address bus; identical voltage thresholds and input leakage as S0 |
| 15 (S2) | Select Line 2 | MSB of address bus; determines selection of I4–I7 when asserted high |
| 16 (VCC) | Positive Supply | Power rail for all internal logic and output drivers; supports 2–6 V; bypass capacitor (0.1 µF) required |
Key Features
| Feature | Design Value |
|---|---|
| 8:1 Multiplexing with True/Complement Outputs | Enables single-package implementation of differential bus drivers or logic-level inversion without external gates |
| Three-State Output Control (OE) | Allows direct connection to shared data buses; eliminates need for external bus transceivers in multi-master systems |
| Extended Temperature Range (–55 °C to 125 °C) | Qualified per MIL-PRF-38535 for use in avionics, missile guidance, and downhole oilfield electronics |
| Low Power Consumption (ICC ≤ 160 µA) | Reduces thermal load in densely packed modules and extends battery life in portable test equipment |
| High Noise Immunity (NIL/NIH = 30% of VCC) | Ensures robust operation in electrically noisy environments such as motor control cabinets and radar subsystems |
Applications
| Avionics Data Acquisition | Military Vehicle Sensor Hub |
|---|---|
|
Use Scenario: Routing analog-to-digital converter outputs from multiple engine sensors (TGT, RPM, vibration) to a central flight computer via shared serial bus. IC Role / Device Role / Timing Role: Digital multiplexer selecting one of eight sensor channels under microcontroller address control; Y/Y̅ outputs feed differential line drivers. Use Value: Eliminates discrete analog switches and level translators; leverages true/complement outputs to meet MIL-STD-1553B common-mode noise rejection requirements. |
Use Scenario: Consolidating status signals from turret stabilization, thermal imaging, and comms subsystems into a vehicle health monitor unit. IC Role / Device Role / Timing Role: Bus-interface multiplexer enabling time-sliced polling of 8 independent subsystems over a shared RS-485 backbone. Use Value: Three-state outputs prevent bus contention during idle cycles; wide temperature range ensures reliability in desert and arctic operational environments. |
| Downhole Oilfield Telemetry | Ruggedized Industrial PLC I/O Expansion |
|
Use Scenario: Multiplexing pressure, temperature, and flow sensor readings from multiple wellbore zones before transmission to surface control. IC Role / Device Role / Timing Role: High-reliability signal selector operating inside sealed, high-pressure probe housings; powered from local 5 V regulator. Use Value: Ceramic CDIP package withstands 200 °C ambient and 15,000 psi pressure; low ICC minimizes self-heating in thermally isolated enclosures. |
Use Scenario: Expanding digital input capacity of legacy PLC racks by aggregating 8 discrete limit switch or proximity sensor signals onto one controller input line. IC Role / Device Role / Timing Role: Logic-level multiplexer interfacing 24 V industrial sensors via level-shifting buffers; OE synchronized to PLC scan cycle. Use Value: Reduces wiring complexity and terminal block count; HC logic thresholds tolerate ±10% supply variation common in factory power distribution. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 8-input multiplexer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| CD54HCT251F | HCT variant: TTL-compatible inputs (VIH = 2 V min, VIL = 0.8 V max); same CDIP-16 package and temperature range | Required where upstream logic is standard LS-TTL or 74LS-series; not suitable for pure CMOS systems with >3.5 V logic swings | Select CD54HCT251F only when interfacing directly with legacy 74LS251-based boards or mixed-logic systems. |
| CD74HC251E | Polymer PDIP-16 package; RoHS-compliant NiPdAu finish; rated –55 °C to 125 °C but not QML-qualified | Acceptable for commercial/industrial upgrades where military certification is not mandated; lower cost and wider distributor availability | Choose CD74HC251E for non-military embedded systems needing same logic function but without QML traceability or hermetic sealing. |
Compared with CD54HC251F, CD54HCT251F offers direct drop-in replacement in TTL-driven systems but sacrifices CMOS noise margin, while CD74HC251E provides identical logic behavior in a lower-cost, RoHS-compliant plastic package - yet lacks the radiation-hardened qualification and hermetic reliability needed for mission-critical deployments.
Availability
CD54HC251F is available at Aetrix Electronics and suitable for avionics data acquisition, military vehicle sensor hubs, and downhole oilfield telemetry requiring stable component supply across extended temperature ranges and long product lifecycles.
Supply support for CD54HC251F 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 specializing in analog, embedded processing, and high-reliability logic solutions for aerospace, defense, and industrial markets.
The CD54HC251F belongs to TI's military-qualified HC logic family, designed specifically for high-integrity data routing in safety-critical systems where extended temperature operation, hermetic packaging, and QML certification are mandatory.
FAQ
What is the absolute maximum supply voltage for CD54HC251F?
The absolute maximum supply voltage for CD54HC251F is 7 V, as specified in Section 5.1 of the TI datasheet (SCHS169D). Operation above this voltage risks permanent device damage. Recommended operating range remains 2–6 V, with 5 V being the nominal design point for timing and drive strength validation. The CD54HC251F must never be subjected to transient overvoltage events exceeding 7 V, even briefly.
Does CD54HC251F support true and complement outputs simultaneously?
Yes, CD54HC251F provides simultaneous true (Y) and complement (Y̅) outputs. Both are active and valid when OE is low, with Y reflecting the selected input and Y̅ its logical inverse. This dual-output capability is intrinsic to the CD54HC251F die design and does not require external inverters - enabling direct interfacing with differential receivers or logic circuits requiring both polarities.
Is CD54HC251F pin-compatible with the 74LS251?
No, CD54HC251F is not pin-compatible with the 74LS251. While functionally similar as 8-input multiplexers, the 74LS251 uses a different pinout: its OE is on pin 13, whereas CD54HC251F places OE on pin 12. Additionally, CD54HC251F has dedicated Y and Y̅ outputs (pins 10 and 11), unlike the 74LS251's single output. Direct substitution requires PCB layout modification.
What is the maximum capacitive load CD54HC251F can drive while maintaining specified propagation delay?
CD54HC251F's specified propagation delay (12 ns typical) is guaranteed at CL = 15 pF, as tested per Section 5.5 of the datasheet. Driving loads beyond 50 pF increases tpd nonlinearly - e.g., at CL = 50 pF, tpd rises to 35 ns max over temperature. For reliable timing closure in high-speed designs, keep total load (including trace and receiver capacitance) ≤15 pF unless derated timing margins are applied.
Can CD54HC251F operate reliably at 2.5 V supply voltage?
Yes, CD54HC251F is fully specified to operate at 2.5 V, within its 2–6 V recommended range. At 2.5 V, VIH = 1.5 V (min), VIL = 0.5 V (max), and tpd increases to 245 ns (max) - suitable for ultra-low-power portable instrumentation where speed is secondary to energy efficiency. All DC parameters remain valid, and the device retains full –55 °C to 125 °C functionality.
CD54HC251F Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 54HC
- Package/Case:
- 16-CDIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Active
- Type:
- Data Selector/Multiplexer
- Circuit:
- 1 x 8:1
- Independent Circuits:
- 1
- Current - Output High, Low:
- 7.8mA, 7.8mA
- Voltage Supply Source:
- Single Supply
- Voltage - Supply:
- 2V ~ 6V
- Operating Temperature:
- -55°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 16-CDIP
CD54HC251F FAQ
1.How can I place an order for CD54HC251F through Aetrix?
Please submit a Request for Quotation (RFQ) for CD54HC251F 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 CD54HC251F reliable?
The price and inventory of CD54HC251F are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for CD54HC251F is usually 5 days.
3.What payment methods are accepted for CD54HC251F?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for CD54HC251F transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for CD54HC251F?
CD54HC251F orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your CD54HC251F 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 CD54HC251F?
For technical support, including CD54HC251F datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your CD54HC251F requirements.
6.How does Aetrix verify that CD54HC251F is sourced from the original manufacturer or authorized distributors?
All CD54HC251F 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 CD54HC251F meets industry standards.
7.What is the process for return or replacement of CD54HC251F?
All CD54HC251F units undergo pre-shipment inspection (PSI). If there is an issue with CD54HC251F, 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 CD54HC251F part is unused and in its original packaging.
Return procedure for CD54HC251F:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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