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Texas Instruments CD74HC257M
- Part No.:
- CD74HC257M
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
CD74HC257M.pdf
- Description:
- IC MULTIPLEXER 4 X 2:1 16SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,618
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Product details
Overview
CD74HC257M from Texas Instruments is a quad 2-input multiplexer with three-state non-inverting outputs, designed for data routing in digital logic systems. It features 2V–6V operation, -55°C to +125°C temperature range, 12ns typical propagation delay at 5V/15pF, and active-low output enable (OE) for bus isolation. It is commonly used in register-to-bus data selection and function generation circuits.
For engineers reviewing the CD74HC257M datasheet, CD74HC257M pinout, CD74HC257M application, or CD74HC257M equivalent, key selection criteria include its SOIC-16 package, HC logic family compatibility, three-state output control, and wide industrial temperature support.
Technical Context
The CD74HC257M implements four independent 2:1 multiplexers sharing one common select (S) input and one active-low output enable (OE). Each channel routes either I0 or I1 to Y based on S state, with all outputs entering high-impedance when OE is HIGH.
Its HC logic family ensures CMOS-level input thresholds (VIH = 1.5V min at 2V VCC; 4.2V min at 6V), 10 LSTTL fanout capability, and balanced rise/fall times. Propagation delays are specified for In→Y (12ns typ), S→Y (14ns typ), and OE→Y (12ns typ) under 5V/15pF conditions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Logic Family | High-speed CMOS (HC), compatible with 2V–6V supply |
| Operating Temperature | -55°C to +125°C - supports extended industrial/military environments |
| Propagation Delay (In→Y) | 12ns typical at VCC = 5V, CL = 15pF - enables fast data switching in synchronous logic |
| Output Type | Three-state non-inverting - allows direct connection to shared buses without contention |
| Input Thresholds | VIH ≥ 1.5V (2V VCC), ≥ 4.2V (6V VCC); VIL ≤ 0.5V (2V VCC), ≤ 1.8V (6V VCC) - ensures robust noise immunity |
| Fanout Capability | 10 LSTTL loads - reduces need for buffer stages in mixed-logic systems |
| Quiescent Current | ≤ 160µA max over full temperature range - supports low-power standby modes |
Pinout & Package
CD74HC257M is housed in a 16-pin SOIC (Small Outline Integrated Circuit) package, surface-mount compatible with standard reflow profiles (MSL Level-1, 260°C peak).
| 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 independent data inputs grouped into four 2-input channels |
| 3, 6, 10, 11 | Outputs (1Y, 2Y, 3Y, 4Y) | Four three-state non-inverting outputs, each controlled by S and OE |
| 9 | Select Input (S) | Common control for all four multiplexers: selects I0 (S=L) or I1 (S=H) |
| 14 | Output Enable (OE) | Active-low global enable: OE=H forces all Y outputs to high-impedance |
| 7 | GND | Ground reference for logic and power |
| 16 | VCC | Positive supply rail (2V–6V) |
Key Features
| Feature | Design Value |
|---|---|
| Buffered inputs | Reduces loading on upstream drivers and improves signal integrity across multiple fanout paths |
| Balanced propagation delay & transition times | Minimizes skew between channels and supports clean timing in parallel data paths |
| High noise immunity (NIL/NIH = 30% of VCC) | Ensures reliable operation in electrically noisy industrial environments without external filtering |
| Significant power reduction vs. LSTTL | Enables higher integration density and lower thermal load in legacy TTL-replacement designs |
| Wide VCC range (2V–6V) | Supports interoperability across 3.3V and 5V systems without level-shifting circuitry |
Applications
| Industrial Control Logic | Digital Test Equipment |
|---|---|
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 analog front-end signals under microcontroller control. Use Value: Enables real-time redundancy switching with minimal added latency (12ns typical delay) and no bus contention due to three-state outputs. |
Use Scenario: Configuring stimulus signal sources (pattern generator vs. external input) per test channel in automated boundary-scan testers. IC Role / Device Role / Timing Role: Data path selector synchronizing with test clock edges in high-speed digital ATE systems. Use Value: Supports deterministic setup/hold timing via matched propagation delays across all four channels, critical for multi-channel parallel testing. |
| Legacy System Upgrades | Embedded Instrumentation |
Use Scenario: Replacing obsolete 74LS257 in retrofitted avionics display controllers requiring extended temperature operation. IC Role / Device Role / Timing Role: Pin-compatible logic upgrade delivering identical functionality with lower power and wider voltage tolerance. Use Value: Eliminates need for redesign while extending operational life through -55°C to +125°C rating and reduced heat dissipation. |
Use Scenario: Routing calibration reference voltages or sensor excitation signals in portable multimeters and data loggers. IC Role / Device Role / Timing Role: Low-power signal selector enabling dynamic reconfiguration of analog measurement paths. Use Value: Quiescent current ≤160µA allows battery-powered operation over extended periods without compromising signal routing flexibility. |
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 |
|---|---|---|---|
| SN74HC257DR | Same logic function, identical pinout, same SOIC-16 package; TI's current production version with updated process and RoHS compliance | Identical use cases; preferred for new designs due to active status and lifecycle support | Select SN74HC257DR for new designs requiring guaranteed long-term availability and modern manufacturing traceability. |
| MC74HC257ADTR2G | Pinout-compatible but manufactured by ON Semiconductor; slightly higher max ICC (200µA vs. 160µA) and different thermal resistance (θJA = 80°C/W vs. 73°C/W) | Acceptable where minor power/thermal margin exists; not recommended for high-density or thermally constrained layouts | Consider MC74HC257ADTR2G only if dual-sourcing is required and thermal derating is verified in final PCB layout. |
Compared with CD74HC257M, SN74HC257DR offers assured supply continuity and updated quality documentation, while MC74HC257ADTR2G provides second-source flexibility at the cost of tighter thermal design margins and less predictable long-term obsolescence risk.
Availability
CD74HC257M is available at Aetrix Electronics and suitable for industrial control logic, digital test equipment, legacy system upgrades, and embedded instrumentation requiring stable component supply across extended temperature ranges.
Supply support for CD74HC257M 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 over 50 years of innovation in high-reliability IC design.
The CD74HC257M belongs to TI's legacy HC logic family, engineered for drop-in replacement of TTL devices in industrial, aerospace, and automotive systems demanding wide temperature operation and low power.
FAQ
What is the supply voltage range supported by the CD74HC257M?
The CD74HC257M operates from 2V to 6V DC, making it compatible with both 3.3V and 5V logic systems. This wide VCC range allows seamless integration into mixed-voltage designs without level shifters. The device maintains specified timing and drive strength across the full range, with VIH/VIL thresholds scaling proportionally to VCC. At 2V, VIH is 1.5V min; at 6V, it rises to 4.2V min - ensuring consistent noise margin.
Does the CD74HC257M support true three-state outputs?
Yes, the CD74HC257M provides true three-state (high-impedance) outputs controlled by the active-low Output Enable (OE) pin. When OE is HIGH, all four Y outputs enter high-Z regardless of S or input states - enabling safe bus sharing in multi-driver systems. This behavior is confirmed in the truth table and functional diagram of the official datasheet (SCHS171D), and is electrically validated by IOZ leakage specs (±10µA max over temperature).
What is the maximum operating temperature for the CD74HC257M?
The CD74HC257M is rated for continuous operation from -55°C to +125°C, meeting extended industrial and military-grade environmental requirements. This specification is explicitly stated in the Ordering Information table and Absolute Maximum Ratings section of the datasheet. Its SOIC package (M suffix) has a θJA of 73°C/W, supporting reliable thermal performance within this range when mounted per JEDEC standards.
Is the CD74HC257M pin-compatible with the 74LS257?
No, the CD74HC257M is not pin-compatible with the 74LS257. While both are quad 2-input multiplexers, the 74LS257 uses open-collector outputs and lacks an OE pin - its outputs are always active. The CD74HC257M has three-state outputs and a dedicated OE input (pin 14), requiring board-level adaptation. However, its logic function and pin numbering for data/select lines align closely, simplifying redesign efforts.
What is the typical propagation delay of the CD74HC257M at 5V?
The CD74HC257M exhibits a typical propagation delay of 12ns from any data input (I0 or I1) to corresponding output (Y) at VCC = 5V, CL = 15pF, and TA = 25°C - as measured per standard JEDEC test conditions. Delays for S→Y and OE→Y are also 14ns and 12ns respectively under identical conditions. These values are guaranteed within published min/max limits across the full temperature and voltage range.
CD74HC257M 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:
- 4 x 2:1
- 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:
- Surface Mount
- Supplier Device Package:
- 16-SOIC
CD74HC257M FAQ
1.How can I place an order for CD74HC257M through Aetrix?
Please submit a Request for Quotation (RFQ) for CD74HC257M 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 CD74HC257M reliable?
The price and inventory of CD74HC257M are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for CD74HC257M is usually 5 days.
3.What payment methods are accepted for CD74HC257M?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for CD74HC257M transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for CD74HC257M?
CD74HC257M orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your CD74HC257M 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 CD74HC257M?
For technical support, including CD74HC257M datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your CD74HC257M requirements.
6.How does Aetrix verify that CD74HC257M is sourced from the original manufacturer or authorized distributors?
All CD74HC257M 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 CD74HC257M meets industry standards.
7.What is the process for return or replacement of CD74HC257M?
All CD74HC257M units undergo pre-shipment inspection (PSI). If there is an issue with CD74HC257M, 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 CD74HC257M part is unused and in its original packaging.
Return procedure for CD74HC257M:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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