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Texas Instruments SN74HC257DG4
- Part No.:
- SN74HC257DG4
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
SN74HC257DG4.pdf
- Description:
- IC MULTIPLEXER 4 X 2:1 16SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,226
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Product details
Overview
SN74HC257DG4 from Texas Instruments is a quadruple 2-line-to-1-line data selector/multiplexer with 3-state outputs, designed for bus-organized digital systems. It operates at 4.5 V–5.5 V, delivers ±6 mA output drive, exhibits 17 ns typical propagation delay at 5.5 V, and features TTL-compatible inputs - enabling direct interface with legacy logic buses in industrial control and instrumentation applications.
For engineers reviewing the SN74HC257DG4 datasheet, SN74HC257DG4 pinout, SN74HC257DG4 application, or SN74HC257DG4 equivalent, key selection criteria include its 3-state bus-driving capability, guaranteed 4.5–5.5 V operation, low 80 µA max ICC, input leakage <1 µA, and compatibility with standard SOIC-16 PCB footprints.
Technical Context
The SN74HC257DG4 implements four independent 2:1 multiplexers sharing a common active-low output-enable (OE) control. Each channel selects between two data inputs (A/B) to drive a dedicated 3-state output (Y), supporting bidirectional bus arbitration and signal routing in synchronous digital subsystems.
Its HCMOS architecture ensures rail-to-rail output swing, buffered inputs prevent loading of upstream drivers, and the high-impedance state (Z) is fully specified across temperature and voltage - critical for hot-swap-capable backplane interfaces and shared-data-path designs.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5 V to 5.5 V - ensures compatibility with 5 V TTL and CMOS logic families without level-shifting. |
| Propagation Delay (tpd) | 17 ns typical at 5.5 V, CL = 50 pF - enables reliable operation in systems with ≤20 MHz clock domains. |
| Output Drive | ±6 mA at 5 V - sufficient to drive 10 LSTTL loads or terminate short PCB traces without external buffers. |
| Quiescent Current (ICC) | 80 µA max - supports low-power standby modes in battery-backed or energy-conscious embedded controllers. |
| Input Leakage | 1 µA max - prevents unintended logic transitions when inputs are tied to pull-up/down resistors. |
| Logic Compatibility | TTL-voltage compatible inputs - accepts 0.8 V/2.0 V thresholds, simplifying integration with legacy microcontrollers and FPGAs. |
| Output State Control | Active-low 3-state enable (OE) - allows multiple devices to share a common bus without contention. |
Pinout & Package
SN74HC257DG4 is housed in a 16-pin SOIC (D) package measuring 9.90 mm × 3.90 mm, with standard 1.27 mm pitch and gull-wing leads suitable for reflow soldering per JEDEC J-STD-020.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | A/B | Channel select control - determines whether input A or B is routed to Y for all four channels. |
| 2–3, 5–6, 10–11, 13–14 | 1A/1B, 2A/2B, 3A/3B, 4A/4B | Data inputs - eight total inputs grouped as four independent 2-input pairs feeding respective multiplexer channels. |
| 4, 7, 9, 12 | 1Y, 2Y, 3Y, 4Y | 3-state outputs - each drives one bus line; high-impedance when OE = high. |
| 8 | GND | Power reference - must be connected to system ground plane for stable noise margin and thermal performance. |
| 15 | G (OE) | Active-low output enable - asserts all four Y outputs simultaneously; tie to VCC via pull-up for power-up safety. |
| 16 | VCC | Positive supply - requires local 0.1 µF ceramic bypass capacitor placed within 5 mm of the pin. |
Key Features
| Feature | Design Value |
|---|---|
| High-current 3-state outputs | Directly drive system buses without external transceivers - reduces component count and layout complexity. |
| Buffered inputs and outputs | Isolates internal logic from capacitive loading and signal reflections - improves timing predictability in multi-load environments. |
| Low input current (≤1 µA) | Minimizes loading on upstream drivers - essential when interfacing with high-impedance sources like DAC outputs or sensor amplifiers. |
| TTL-compatible input thresholds | Eliminates need for level translators when connecting to 5 V microcontrollers, PLDs, or legacy peripherals. |
| Guaranteed 4.5–5.5 V operation | Supports robust performance across wide supply tolerances - critical for industrial power rails with ±10% variation. |
Applications
| Industrial PLC I/O Expansion | Legacy Bus Interface Adapter |
|---|---|
|
Use Scenario: Expanding discrete I/O points in programmable logic controllers using shared data/address buses. IC Role / Device Role / Timing Role: Data selector routing sensor status or actuator commands from parallel input banks onto a common 4-bit data bus. Use Value: Enables cost-effective reuse of existing 4-bit bus infrastructure while adding modular I/O capacity without FPGA logic overhead. |
Use Scenario: Bridging modern microcontroller GPIOs to legacy 5 V TTL peripheral interfaces (e.g., EPROMs, UARTs, display drivers). IC Role / Device Role / Timing Role: Multiplexing multiple peripheral data lines onto a single MCU port while maintaining bus isolation during idle cycles. Use Value: Eliminates need for discrete MOSFET switches or complex glue logic - reduces BOM count and board area in retrofit designs. |
| Digital Test Equipment Signal Routing | Embedded System Debug Port Multiplexer |
|
Use Scenario: Selecting between multiple DUT (device-under-test) signal sources in automated test fixtures. IC Role / Device Role / Timing Role: Channel-selectable 2:1 multiplexer providing deterministic path switching under microcontroller control. Use Value: Delivers sub-20 ns propagation delay and rail-to-rail output swing - preserves signal integrity for high-speed digital stimulus/response verification. |
Use Scenario: Sharing a single debug UART or SWD port among multiple subsystems (e.g., motor control, sensor hub, comms module) in resource-constrained MCUs. IC Role / Device Role / Timing Role: 3-state bus switch enabling time-division access to shared debug hardware without hardware conflicts. Use Value: Prevents bus contention during firmware updates or diagnostics - avoids reset loops and communication lockups in field-deployed devices. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 2:1 multiplexer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74HCT257DR | Same logic function and pinout; HCT family offers tighter input threshold matching to TTL but identical 4.5–5.5 V range and 3-state behavior. | Preferred where strict TTL-level noise immunity is required in mixed-logic systems with older components. | Select SN74HCT257DR if interfacing directly with 74LS or 74ALS families; otherwise SN74HC257DG4 provides broader voltage margin and lower ICC. |
| 74VHC257M | Pin-compatible; operates down to 2 V and up to 5.5 V, with faster 10 ns tpd but higher 100 µA ICC and reduced 4 mA output drive. | Better suited for dual-supply or low-voltage portable systems where 5 V-only operation is not mandatory. | Choose 74VHC257M only when system supply varies below 4.5 V; SN74HC257DG4 remains optimal for fixed 5 V industrial designs. |
Compared with SN74HCT257DR and 74VHC257M, SN74HC257DG4 delivers the best balance of 5 V bus compatibility, ultra-low quiescent current, and robust output drive - making it the preferred choice for cost-sensitive, thermally constrained, and long-lifecycle industrial control applications.
Availability
SN74HC257DG4 is available at Aetrix Electronics and suitable for industrial PLC expansion, legacy bus interface adapters, digital test equipment signal routing, embedded debug port multiplexing, and 5 V logic consolidation requiring stable component supply across extended production cycles.
Supply support for SN74HC257DG4 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, embedded processing, and connectivity solutions for industrial, automotive, and communications markets.
The SN74HC257DG4 belongs to TI's 74HC logic family - engineered for high-speed, low-power 5 V digital signal routing in industrial control, instrumentation, and legacy-system interface applications.
FAQ
What is the operating voltage range for SN74HC257DG4?
The SN74HC257DG4 operates over a supply voltage range of 4.5 V to 5.5 V. This specification ensures full functionality and guaranteed timing performance across standard 5 V power rails with ±10% tolerance. Operation outside this range may result in undefined logic states or increased ICC, and is not supported per TI's recommended operating conditions.
Does SN74HC257DG4 support true 3-state outputs?
Yes, SN74HC257DG4 provides fully specified 3-state outputs controlled by the active-low G (OE) pin. When OE is high, all four Y outputs enter a high-impedance state with leakage current ≤±5 µA at 5.5 V - enabling safe bus sharing without contention. This behavior is verified across temperature and voltage per TI's electrical characteristics table.
What is the typical propagation delay of SN74HC257DG4?
The typical propagation delay (tpd) of SN74HC257DG4 is 17 ns at VCC = 5.5 V and CL = 50 pF. This value reflects the worst-case transition from A/B or OE input to Y output under standard test conditions and is confirmed in TI's switching characteristics table for both SN74HC257 and SN74HCT257 variants.
Can SN74HC257DG4 interface directly with TTL logic?
Yes, SN74HC257DG4 features TTL-voltage compatible inputs - meaning it recognizes VIH ≥ 2.0 V and VIL ≤ 0.8 V across the full 4.5–5.5 V supply range. This allows direct connection to 74LS, 74ALS, and other TTL-family outputs without level-shifting circuitry, as explicitly stated in TI's device features and input specifications.
What package type is used for SN74HC257DG4?
SN74HC257DG4 uses a 16-pin SOIC (D) package with body dimensions of 9.90 mm × 3.90 mm and 1.27 mm lead pitch. This surface-mount footprint is industry-standard, compatible with automated assembly processes, and documented in TI's mechanical data and packaging addendum for the SN74HC257 series.
SN74HC257DG4 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74HC
- Package/Case:
- 16-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tube
- Product Status:
- Discontinued at Digi-Key
- 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:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-SOIC
SN74HC257DG4 FAQ
1.How can I place an order for SN74HC257DG4 through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74HC257DG4 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 SN74HC257DG4 reliable?
The price and inventory of SN74HC257DG4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74HC257DG4 is usually 5 days.
3.What payment methods are accepted for SN74HC257DG4?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74HC257DG4 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74HC257DG4?
SN74HC257DG4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74HC257DG4 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 SN74HC257DG4?
For technical support, including SN74HC257DG4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74HC257DG4 requirements.
6.How does Aetrix verify that SN74HC257DG4 is sourced from the original manufacturer or authorized distributors?
All SN74HC257DG4 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 SN74HC257DG4 meets industry standards.
7.What is the process for return or replacement of SN74HC257DG4?
All SN74HC257DG4 units undergo pre-shipment inspection (PSI). If there is an issue with SN74HC257DG4, 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 SN74HC257DG4 part is unused and in its original packaging.
Return procedure for SN74HC257DG4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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