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Texas Instruments SN74HC257PW
- Part No.:
- SN74HC257PW
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
SN74HC257PW.pdf
- Description:
- IC MULTIPLEXER 4 X 2:1 16TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:163
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Product details
Overview
SN74HC257PW from Texas Instruments is a quadruple 2-line to 1-line data selector/multiplexer with 3-state non-inverting outputs, operating across 2 V–6 V supply, delivering 9 ns typical propagation delay at 4.5 V, ±6 mA output drive, and 80 µA max ICC. It enables bus interface in digital logic systems where four independent 2:1 multiplexing channels share common address (A/B) and active-low enable (G) controls.
For engineers reviewing the SN74HC257PW datasheet, SN74HC257PW pinout, SN74HC257PW application, or SN74HC257PW equivalent, this page provides verified functional identity, TSSOP-16 package mapping, confirmed 3-state non-inverting output behavior, absolute maximum ratings, and validated alternative options for logic-level signal routing in space-constrained industrial control and instrumentation designs.
Technical Context
The SN74HC257PW implements four independent 2:1 multiplexers sharing one address pair (A/B) and one active-low output-enable (G) input. When G is high, all Y outputs enter high-impedance state; when G is low, each Y selects A or B based on the A/B input level. Its HC logic family ensures CMOS-level compatibility with TTL loads.
It operates within −40°C to +85°C ambient temperature, supports 50 pF load capacitance per channel, and features input clamp current rating of ±20 mA and junction-to-ambient thermal resistance of 108 °C/W in TSSOP package - critical for thermal-aware PCB layout in dense logic subsystems.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage Range | 2 V to 6 V - compatible with 3.3 V and 5 V logic domains without level translation |
| Propagation Delay (tpd) | 9 ns typical at VCC = 4.5 V, CL = 50 pF - enables sub-100 MHz clock-domain multiplexing |
| Output Drive | ±6 mA at 5 V - sufficient to drive 15 LSTTL loads directly |
| Quiescent Current (ICC) | 80 µA max at 6 V - supports low-power standby modes in battery-backed systems |
| Input Leakage Current | ±1 µA max - ensures stable logic levels with high-impedance source interfaces |
| 3-State Enable/Disable Time | 25 ns max ten/tdis at 4.5 V - guarantees clean bus arbitration timing in shared-data-path applications |
| Power Dissipation Capacitance | 40 pF per multiplexer - used to calculate dynamic power consumption in high-frequency switching |
Pinout & Package
TSSOP-16 package (5.00 mm × 4.40 mm body size, 1.2 mm max height), lead finish NIPDAU/SN, moisture sensitivity level 1, RoHS compliant.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (G) | Active-low output enable | Drives all Y outputs to high-impedance when logic high; must be pulled up during power-up for safe default state |
| 2 (A) | Address select input | Common control for all four multiplexers: selects A-input (low) or B-input (high) for each Y output |
| 3 (B1) | Data input channel 1, B-side | One of two inputs routed to Y1 based on A/B state; shares no internal connection with other B pins |
| 4 (A1) | Data input channel 1, A-side | One of two inputs routed to Y1; electrically isolated from A2–A4 except via shared A control pin |
| 5 (Y1) | Output channel 1 | Non-inverting 3-state output; reflects A1 or B1 depending on A/B and G states |
| 6 (B2) | Data input channel 2, B-side | Independent B-input for Y2; no internal fanout or coupling to B1/B3/B4 |
| 7 (A2) | Data input channel 2, A-side | Independent A-input for Y2; functionally identical to A1 but physically separate |
| 8 (GND) | Ground reference | Primary return path for all I/O and supply currents; requires low-inductance connection to system ground plane |
| 9 (Y2) | Output channel 2 | Non-inverting 3-state output synchronized to A/B and G; matches Y1 timing within device specs |
| 10 (A3) | Data input channel 3, A-side | Third independent A-input; no shared logic or routing with A1/A2/A4 |
| 11 (B3) | Data input channel 3, B-side | Third independent B-input; maintains full channel isolation per datasheet functional table |
| 12 (Y3) | Output channel 3 | Non-inverting 3-state output; identical electrical characteristics to Y1/Y2/Y4 |
| 13 (A4) | Data input channel 4, A-side | Final A-input; completes quad-mux set; no internal dependency on prior A pins |
| 14 (B4) | Data input channel 4, B-side | Final B-input; fully independent; supports simultaneous 4-channel selection |
| 15 (Y4) | Output channel 4 | Non-inverting 3-state output; matches propagation and transition specs of Y1–Y3 |
| 16 (VCC) | Positive supply | Single power rail for all logic and output stages; requires local 0.1 µF bypass capacitor |
Key Features
| Feature | Design Value |
|---|---|
| Quad 2:1 multiplexing with shared control | Reduces component count vs. discrete mux ICs while maintaining independent data paths for four signals |
| 3-state non-inverting outputs | Enables direct connection to shared data buses without external pull-ups or direction control logic |
| Wide 2–6 V supply range | Supports mixed-voltage system integration (e.g., 3.3 V MCU controlling 5 V peripherals) |
| Low ICC (80 µA max) | Minimizes quiescent power in always-on monitoring circuits or sleep-mode logic subsystems |
| High noise immunity (VIH/VIL thresholds) | Guaranteed 3.15 V VIH min at 4.5 V VCC ensures robust operation in noisy industrial environments |
| TSSOP-16 footprint | 5.0 × 4.4 mm body enables compact placement in space-limited embedded controllers and test equipment |
Applications
| Industrial PLC I/O Expansion | Digital Test Equipment Signal Routing |
|---|---|
Use Scenario: Multiplexing sensor analog front-end outputs or digital status lines into a single microcontroller ADC or GPIO port. IC Role / Device Role / Timing Role: SN74HC257PW acts as a synchronous 4-channel analog/digital signal selector, controlled by MCU GPIOs driving A/B and G. Use Value: Eliminates need for four separate mux ICs or FPGA logic resources, reducing BOM cost and PCB area by >60% in modular I/O modules. |
Use Scenario: Dynamically reconfiguring stimulus/response paths between DUT pins and measurement instruments in automated test fixtures. IC Role / Device Role / Timing Role: SN74HC257PW serves as a fast-switching, low-glitch signal router enabling <100 ns path reconfiguration under software control. Use Value: Achieves deterministic 9 ns propagation delay and 25 ns enable timing - critical for sub-microsecond test sequence synchronization. |
| Embedded System Bus Interface | Legacy Peripheral Address Decoding |
Use Scenario: Isolating multiple memory-mapped peripherals onto a shared data bus in resource-constrained microcontrollers. IC Role / Device Role / Timing Role: SN74HC257PW functions as a 3-state bus gate, enabling/disabling peripheral data lines using address-decoded G signal. Use Value: Provides ±6 mA drive strength and high-impedance isolation, preventing bus contention without external bus transceivers. |
Use Scenario: Selecting between parallel EEPROM, SRAM, and I/O register banks in 8-bit microprocessor-based designs. IC Role / Device Role / Timing Role: SN74HC257PW implements address-selectable memory banking using A/B as LSB/MUX control and G as chip-select derivative. Use Value: Delivers guaranteed 25 ns enable/disable timing and 9 ns propagation - meets tight setup/hold windows of legacy 8051/6502 systems. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar quad 2:1 multiplexer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74HC157DR | Same logic function and pinout; SOIC-16 package; 108 °C/W RθJA vs. 108 °C/W for PW (identical thermal spec) | SOIC-16 footprint requires larger PCB area; lacks TSSOP's 0.65 mm pitch advantage for high-density layouts | Select SN74HC157DR only if SOIC assembly infrastructure is already in place and board space permits. |
| SN74LVC157APWR | Lower VCC range (1.65–3.6 V); faster tpd (5.1 ns typ at 3.3 V); 32 mA drive; different input thresholds | Not suitable for 5 V systems; requires level-shifting when interfacing with 5 V peripherals or legacy logic | Choose SN74LVC157APWR only for pure 3.3 V designs demanding higher speed and drive, not as drop-in replacement. |
Compared with SN74HC157DR and SN74LVC157APWR, the SN74HC257PW uniquely balances 2–6 V operation, TSSOP-16 compactness, and proven 9 ns timing - making it optimal for mixed-voltage industrial controllers where footprint and voltage flexibility outweigh raw speed.
Availability
SN74HC257PW is available at Aetrix Electronics and suitable for industrial PLC I/O expansion, digital test equipment signal routing, embedded system bus interface, and legacy peripheral address decoding requiring stable component supply and long-term design continuity.
Supply support for SN74HC257PW 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 logic families.
The SN74HC257PW belongs to TI's 74HC logic series, designed for general-purpose digital signal routing in industrial, automotive, and communications systems where wide supply range, predictable timing, and 3-state bus compatibility are essential.
FAQ
What is the function of the G pin on the SN74HC257PW?
The G pin on the SN74HC257PW is the active-low output-enable input. When G is high, all four Y outputs enter high-impedance state regardless of A/B or data inputs. When G is low, the outputs reflect the selected A or B inputs per the function table. For safe power-up behavior, TI recommends tying G to VCC via a pullup resistor.
Does the SN74HC257PW support 5 V operation?
Yes, the SN74HC257PW supports 5 V operation within its specified 2 V–6 V supply range. At VCC = 5 V, it delivers ±6 mA output drive, 9 ns typical propagation delay (CL = 50 pF), and meets all recommended operating conditions including VIH ≥ 3.5 V and VIL ≤ 1.5 V per the datasheet.
Is the SN74HC257PW pin-compatible with the SN74HC157?
Yes, the SN74HC257PW is functionally and pin-compatible with the SN74HC157 series, including SN74HC157DR and SN74HC157N. Both share identical pin assignments, logic function, and truth table. The '257' and '157' designations refer to the same device - TI uses both part number prefixes interchangeably for this quad 2:1 mux.
What is the maximum capacitive load the SN74HC257PW can drive reliably?
The SN74HC257PW is characterized for reliable operation with up to 50 pF load capacitance per output, as specified in the switching characteristics table. While it may function with higher loads, propagation delay increases (e.g., 32 ns max at CL = 150 pF, VCC = 4.5 V), and transition times degrade - design margins should be verified per actual board trace capacitance.
Can unused inputs on the SN74HC257PW be left floating?
No, unused inputs on the SN74HC257PW must not be left floating. TI specifies that all unused inputs must be tied to VCC or GND to ensure proper device operation and prevent undefined logic states or increased power consumption. This applies to all A, B, and G inputs not actively used in the design.
SN74HC257PW Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74HC
- Package/Case:
- 16-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Bulk
- 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:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-TSSOP
SN74HC257PW FAQ
1.How can I place an order for SN74HC257PW through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74HC257PW 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 SN74HC257PW reliable?
The price and inventory of SN74HC257PW are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74HC257PW is usually 5 days.
3.What payment methods are accepted for SN74HC257PW?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74HC257PW transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74HC257PW?
SN74HC257PW orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74HC257PW 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 SN74HC257PW?
For technical support, including SN74HC257PW datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74HC257PW requirements.
6.How does Aetrix verify that SN74HC257PW is sourced from the original manufacturer or authorized distributors?
All SN74HC257PW 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 SN74HC257PW meets industry standards.
7.What is the process for return or replacement of SN74HC257PW?
All SN74HC257PW units undergo pre-shipment inspection (PSI). If there is an issue with SN74HC257PW, 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 SN74HC257PW part is unused and in its original packaging.
Return procedure for SN74HC257PW:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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