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Texas Instruments CD74HCT257M
- Part No.:
- CD74HCT257M
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
CD74HCT257M.pdf
- Description:
- IC MULTIPLEXER 4 X 2:1 16SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,628
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Product details
Overview
CD74HCT257M from Texas Instruments is a quad 2-input multiplexer with three-state non-inverting outputs, designed for data routing in digital logic systems operating at 4.5V–5.5V. It features 12ns typical propagation delay (In to Y, VCC = 5V, CL = 15pF), -55°C to +125°C operating temperature range, and active-low Output Enable (OE) enabling bus isolation. It is commonly used in register-to-bus data selection and function generation circuits.
For engineers reviewing the CD74HCT257M datasheet, CD74HCT257M pinout, CD74HCT257M application, or CD74HCT257M equivalent, key selection criteria include its HCT-level LSTTL input compatibility (VIH ≥ 2V, VIL ≤ 0.8V), 16-pin SOIC package, three-state output control, and guaranteed operation across extended industrial/military temperature ranges.
Technical Context
The CD74HCT257M implements four independent 2:1 multiplexers sharing one common Select (S) input and one active-low Output Enable (OE) control. Each multiplexer routes either I0 or I1 to its Y output based on S state, while OE asserts high-impedance on all Y outputs when HIGH.
Its HCT logic family ensures direct compatibility with LSTTL inputs and CMOS power efficiency, with balanced propagation delays (tPLH/tPHL ≤ 13ns typ. at 5V/15pF), low input leakage (≤1µA), and robust noise immunity (NIL/NIH = 30% of VCC).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Logic Family | HCT - compatible with LSTTL inputs and CMOS power efficiency |
| Supply Voltage Range | 4.5V to 5.5V - ensures stable operation in standard 5V TTL-compatible systems |
| Propagation Delay (In→Y) | 13ns typical at VCC = 5V, CL = 15pF - enables reliable timing in 30+ MHz data paths |
| Operating Temperature | -55°C to +125°C - supports military, automotive, and harsh-environment applications |
| Output Type | Three-state non-inverting - allows shared bus driving with controlled enable/disable |
| Input Compatibility | LSTTL: VIH ≥ 2V, VIL ≤ 0.8V - eliminates need for level-shifting in mixed-logic systems |
| Quiescent Current | ≤160µA max over full temp range - minimizes standby power in battery-sensitive designs |
Pinout & Package
CD74HCT257M is housed in a 16-pin SOIC (Small Outline Integrated Circuit) package, surface-mount compatible with JEDEC MS-012AC, 1.27mm pitch, and RoHS-compliant NIPDAU lead finish.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2, 4, 5, 12, 13, 15, 16 | Data Inputs (1I0, 1I1, 2I0, 2I1, 3I0, 3I1, 4I0, 4I1) | Eight parallel data sources - two per multiplexer channel |
| 3, 14 | Select (S) and Output Enable (OE) | Global control: S chooses I0/I1 source; OE = HIGH disables all outputs to high-Z |
| 6, 8, 10, 11 | Outputs (1Y, 2Y, 3Y, 4Y) | Four buffered, three-state, non-inverting outputs - drive shared buses or downstream logic |
| 7 | GND | Ground reference for logic and power return path |
| 16 | VCC | Positive supply rail - must be 4.5V–5.5V for HCT compliance |
Key Features
| Feature | Design Value |
|---|---|
| Buffered inputs | Reduces loading on upstream drivers and improves signal integrity across PCB traces |
| Three-state outputs with active-low OE | Enables multi-device bus sharing without external gating or contention risk |
| Balanced tPLH/tPHL and transition times | Minimizes duty-cycle distortion and setup/hold margin violations in clocked systems |
| High noise immunity (30% VCC) | Ensures reliable switching in electrically noisy environments such as motor controls or power supplies |
| Extended temperature support (-55°C to +125°C) | Validates functionality in aerospace, defense, and under-hood automotive electronics |
Applications
| Industrial Control Logic | Test Equipment Data Routing |
|---|---|
|
Use Scenario: Selecting between primary and backup sensor data streams before ADC sampling in PLC I/O modules. IC Role / Device Role / Timing Role: Quad 2:1 multiplexer routing dual-channel analog front-end signals to a single ADC interface. Use Value: Enables real-time redundancy switching with sub-15ns decision latency and no bus contention during transitions. |
Use Scenario: Dynamically configuring signal paths in automated test equipment (ATE) channel cards. IC Role / Device Role / Timing Role: Bus-select gate for routing calibration references or DUT outputs to measurement circuitry. Use Value: Provides deterministic, glitch-free path selection synchronized to system control clocks with minimal added skew. |
| Military Avionics Interface | Digital Function Generator |
|
Use Scenario: Multiplexing discrete status bits from multiple line-replaceable units (LRUs) onto a shared MIL-STD-1553 bus monitor line. IC Role / Device Role / Timing Role: Level-translating, temperature-hardened data selector interfacing legacy TTL subsystems with modern bus controllers. Use Value: Guarantees correct logic levels and timing margins across -55°C to +125°C without derating or external conditioning. |
Use Scenario: Implementing combinational logic truth tables using hardwired inputs and select lines in programmable logic demonstrators. IC Role / Device Role / Timing Role: Configurable logic block generating Boolean functions (e.g., XOR, AND-OR-INVERT) via input pin strapping. Use Value: Delivers predictable, race-free output transitions with <15ns propagation and matched rise/fall times. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar quad 2-input multiplexer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74HCT257N | Same HCT logic, identical pinout and AC/DC specs; PDIP package instead of SOIC | Preferred for through-hole prototyping or legacy board rework where SOIC footprint is unavailable | Choose SN74HCT257N only if manual soldering or socket-based testing is required |
| CD74HC257M | HC variant: 2V–6V supply range, higher VIH/VIL thresholds, slightly slower propagation (15ns typ.) | Suitable for mixed-voltage systems (e.g., 3.3V control + 5V peripherals) but not LSTTL-input compatible | Select CD74HC257M only when wider VCC range or lower static power is prioritized over TTL interoperability |
Compared with SN74HCT257N and CD74HC257M, the CD74HCT257M uniquely delivers LSTTL input compatibility in a space-saving SOIC package with guaranteed -55°C to +125°C operation-making it optimal for high-reliability surface-mount deployments requiring direct TTL integration.
Availability
CD74HCT257M is available at Aetrix Electronics and suitable for industrial control logic, test equipment data routing, military avionics interface, and digital function generator applications requiring stable component supply across extended temperature ranges.
Supply support for CD74HCT257M 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 logic solutions, with decades of heritage in high-reliability logic families including the 74HCT series.
The CD74HCT257M belongs to TI's legacy 74HCT logic portfolio, engineered for seamless integration into mixed-technology systems requiring LSTTL-compatible inputs, low-power CMOS operation, and extended-temperature reliability.
FAQ
What is the maximum operating frequency supported by the CD74HCT257M?
The CD74HCT257M does not specify a maximum clock frequency directly, but its 13ns typical propagation delay (In to Y, VCC = 5V, CL = 15pF) supports reliable operation in data paths up to approximately 30 MHz under typical loading conditions. System-level timing must account for worst-case delays (45ns max over -55°C to +125°C) and board-level signal integrity.
Can the CD74HCT257M operate from a 3.3V supply?
No - the CD74HCT257M is an HCT-family device specified only for 4.5V to 5.5V operation. At 3.3V, input thresholds (VIH ≥ 2V, VIL ≤ 0.8V) become unreliable and DC parameters fall outside specification. For 3.3V systems, consider the CD74HC257M or SN74LVC257A instead.
Is the CD74HCT257M pin-compatible with the SN74LS257?
Yes - the CD74HCT257M shares identical pinout, function, and truth table with the SN74LS257, including active-low OE and common S input. However, CD74HCT257M offers CMOS power consumption, higher noise immunity, and extended temperature range versus the bipolar LS version.
What is the purpose of the "96" suffix in CD74HCT257M96.A?
The "96" suffix in CD74HCT257M96.A indicates tape-and-reel packaging: 2500 units per reel, SOIC-D package, Q1 pin-1 orientation, and RoHS-compliant NIPDAU finish. The "A" denotes a revision-controlled manufacturing lot compliant with TI's current quality and environmental standards.
Does the CD74HCT257M require pull-up or pull-down resistors on unused inputs?
Unused inputs on the CD74HCT257M should be terminated to VCC or GND to prevent floating states that increase dynamic power and risk metastability. TI recommends tying unused I0/I1 inputs to GND or VCC, and leaving S and OE actively driven - especially OE, since floating OE may inadvertently enable outputs and cause bus contention.
CD74HCT257M Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74HCT
- Package/Case:
- 16-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Type:
- Multiplexer
- Circuit:
- 4 x 2:1
- Independent Circuits:
- 1
- Current - Output High, Low:
- 6mA, 6mA
- Voltage Supply Source:
- Single Supply
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -55°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-SOIC
CD74HCT257M FAQ
1.How can I place an order for CD74HCT257M through Aetrix?
Please submit a Request for Quotation (RFQ) for CD74HCT257M 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 CD74HCT257M reliable?
The price and inventory of CD74HCT257M are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for CD74HCT257M is usually 5 days.
3.What payment methods are accepted for CD74HCT257M?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for CD74HCT257M transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for CD74HCT257M?
CD74HCT257M orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your CD74HCT257M 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 CD74HCT257M?
For technical support, including CD74HCT257M datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your CD74HCT257M requirements.
6.How does Aetrix verify that CD74HCT257M is sourced from the original manufacturer or authorized distributors?
All CD74HCT257M 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 CD74HCT257M meets industry standards.
7.What is the process for return or replacement of CD74HCT257M?
All CD74HCT257M units undergo pre-shipment inspection (PSI). If there is an issue with CD74HCT257M, 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 CD74HCT257M part is unused and in its original packaging.
Return procedure for CD74HCT257M:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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