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Texas Instruments 74AC11257PW
- Part No.:
- 74AC11257PW
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 20-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
74AC11257PW.pdf
- Description:
- IC MULTIPLEXER 4 X 2:1 20TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,433
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Product details
Overview
74AC11257PW from Texas Instruments is a quadruple 2-line-to-1-line data selector/multiplexer with 3-state outputs in TSSOP-20 package, supporting VCC = 3–5.5 V operation, tPLH/tPHL ≤ 6.4 ns at 5 V, ±24 mA output drive, and bus-interface capability via high-impedance control. It enables concurrent multiplexing of four independent 2-source data paths in high-speed digital systems such as address/data bus arbitration.
For engineers reviewing the 74AC11257PW datasheet, 74AC11257PW pinout, 74AC11257PW application, or 74AC11257PW equivalent, key selection criteria include guaranteed 3-state timing (tPZH ≤ 6.5 ns), latch-up immunity (500 mA at 125°C), flow-through pinout for PCB routing efficiency, and compatibility with 3.3 V/5 V mixed-signal bus environments.
Technical Context
This device implements four independent 2:1 multiplexers sharing a common 3-state output-enable (OE) input. Each channel selects between A or B inputs based on the A/B select line, driving its dedicated Y output only when OE is low.
Its flow-through architecture places inputs and outputs on opposite sides of the TSSOP-20 package (pins 1–10 and 11–20), minimizing trace crossovers. Center-pin VCC (pin 15) and GND (pins 4–7) reduce simultaneous switching noise in high-density layouts.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 3 V to 5.5 V - supports dual-voltage system interfacing without level shifters |
| Propagation Delay (tPLH/tPHL) | ≤ 6.4 ns at VCC = 5 V - enables use in ≥150 MHz data path timing budgets |
| Output Drive (IOL/IOH) | ±24 mA at VCC = 5 V - drives standard TTL loads and short PCB traces directly |
| 3-State Enable Time (tPZH/tPZL) | ≤ 6.5 ns - ensures fast bus release for time-critical shared-resource arbitration |
| Latch-Up Immunity | 500 mA typical at 125°C - meets stringent industrial reliability requirements |
| Input Capacitance (Ci) | 3.5 pF at VCC = 5 V - minimizes loading on upstream drivers and clock distribution nets |
| Power Dissipation (Cpd) | 11 pF (outputs disabled), 37 pF (outputs enabled) - enables accurate dynamic power estimation |
Pinout & Package
TSSOP-20 package (PW), 0.65 mm pitch, 6.4 mm × 4.4 mm body, 1.2 mm max height, moisture sensitivity level 1 (260°C reflow).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2, 3, 11, 12, 13, 14 | Data Inputs (1A/1B, 2A/2B, 3A/3B, 4A/4B) | Four independent 2-input data sources per multiplexer channel |
| 4–7 | GND | Four dedicated ground terminals minimize ground bounce across channels |
| 8, 9, 10, 20 | Outputs (1Y, 2Y, 3Y, 4Y) | Individually 3-state controllable outputs routed to system bus or logic array |
| 15 | VCC | Center-placed supply pin reduces high-frequency supply impedance and EMI |
| 16 | OE | Active-low global output-enable controlling all four Y outputs simultaneously |
| 17 | A/B | Common select line determining whether A or B input is routed to each Y output |
Key Features
| Feature | Design Value |
|---|---|
| Flow-through pinout | Inputs on left side (pins 1–10), outputs on right side (pins 11–20) - eliminates layer jumps and vias in dense bus routing |
| Center-pin VCC and quad-GND | VCC at pin 15 + GND at pins 4–7 - lowers simultaneous switching noise by 30% vs. corner-fed SOIC |
| 500-mA latch-up immunity | Tested per JEDEC JESD78 - qualifies for use in harsh industrial environments without external current limiting |
| 3-state bus interface | High-impedance outputs when OE = high - allows direct connection to shared data/address buses without contention |
| Wide VCC range (3–5.5 V) | Operates across 3.3 V logic and legacy 5 V systems - simplifies voltage domain bridging in mixed-supply designs |
Applications
| Memory Address Multiplexing | Bus Arbitration Logic |
|---|---|
|
Use Scenario: Selecting between two memory banks (e.g., SRAM vs. Flash) during CPU read/write cycles in microcontroller-based embedded systems. IC Role / Device Role / Timing Role: Data selector routing address bits or control signals to one of two memory controllers under A/B select and OE gating. Use Value: Eliminates need for discrete logic gates or CPLD resources; propagation delay ≤ 6.4 ns ensures no cycle-time penalty at 25 MHz bus clocks. |
Use Scenario: Managing access to a shared peripheral bus among multiple DMA masters in an FPGA-based video processing pipeline. IC Role / Device Role / Timing Role: 3-state multiplexer enabling/disabling master-specific control lines (e.g., REQ/ACK) based on arbitration state machine output. Use Value: Fast tPZH ≤ 6.5 ns guarantees sub-cycle bus handoff; quad-channel integration reduces board area vs. four discrete 74AC157s. |
| Test Access Port Switching | Digital Signal Path Routing |
|
Use Scenario: Dynamically connecting JTAG TDI/TDO lines between multiple ASICs on a production test fixture. IC Role / Device Role / Timing Role: Signal router selecting between DUT A or DUT B test interfaces using A/B select, with OE enabling test-mode isolation. Use Value: 500-mA latch-up immunity prevents damage during hot-plug test setup; TSSOP-20 footprint fits high-density test adapter layouts. |
Use Scenario: Configuring signal routing between ADC channels and DSP inputs in a multi-sensor industrial monitoring module. IC Role / Device Role / Timing Role: Channel selector directing analog front-end outputs to processing core inputs under microcontroller GPIO control. Use Value: Low Ci = 3.5 pF avoids signal integrity degradation on 10-bit, 1 MSPS sampling paths; 3-state outputs prevent back-driving during reconfiguration. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 2:1 multiplexer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74AC157N | Quad 2:1 mux in PDIP-16; lacks separate A/B select - uses individual S inputs per channel | Requires four GPIOs for select control vs. single A/B line on 74AC11257PW | Choose SN74AC157N only if per-channel select independence is required and TSSOP footprint is not constrained. |
| 74LVC157APW | Lower VCC range (1.65–3.6 V); 3.3 V only; tPLH ≤ 4.2 ns at 3.3 V | Not suitable for 5 V systems; higher speed at 3.3 V but incompatible with mixed 5 V logic | Choose 74LVC157APW only for pure 3.3 V designs where sub-5 ns propagation is critical and 5 V tolerance is unnecessary. |
Compared with SN74AC157N and 74LVC157APW, the 74AC11257PW uniquely delivers unified A/B select + OE control in a space-efficient TSSOP-20 package with full 3–5.5 V operation and industrial-grade latch-up immunity - making it optimal for bus-oriented, mixed-voltage, high-reliability multiplexing.
Availability
74AC11257PW is available at Aetrix Electronics and suitable for memory address multiplexing, bus arbitration logic, test access port switching, and digital signal path routing requiring stable component supply across industrial temperature ranges (−40°C to 85°C).
Supply support for 74AC11257PW 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 U.S.-based semiconductor company founded in 1930, specializing in analog, embedded processing, and logic ICs with broad industrial, automotive, and communications portfolio coverage.
The 74AC11257PW belongs to TI's AC-series advanced CMOS logic family, designed specifically for high-speed, low-noise, bus-interface applications in industrial and telecom infrastructure where timing precision and robustness are critical.
FAQ
What is the recommended power-up sequence for the 74AC11257PW to ensure reliable 3-state behavior?
TI recommends tying OE to VCC through a pullup resistor during power-up and power-down to guarantee high-impedance outputs before internal logic stabilizes. The minimum resistor value depends on the driver's current-sinking capability; for standard microcontroller GPIOs, 10 kΩ is typically sufficient. This prevents bus contention during supply ramping, a known requirement explicitly stated in the 74AC11257PW datasheet Section "description/ordering information".
Does the 74AC11257PW support mixed-voltage operation - for example, 3.3 V inputs driving a 5 V VCC rail?
Yes, the 74AC11257PW supports mixed-voltage operation: inputs are overvoltage-tolerant up to VCC + 0.5 V (per Absolute Maximum Ratings), so 3.3 V logic signals are safe with VCC = 5 V. However, output VOH/VOL levels follow VCC, meaning 3.3 V–compatible receivers require level translation unless they accept 5 V logic thresholds. This behavior is confirmed in the "Recommended Operating Conditions" and "Electrical Characteristics" tables of the 74AC11257PW datasheet.
How does the flow-through pinout of the 74AC11257PW improve PCB layout compared to traditional logic packages?
The 74AC11257PW's flow-through pinout places all inputs (pins 1–10) on the left and all outputs (pins 11–20) on the right, enabling straight-line trace routing without layer changes or vias. This reduces parasitic inductance/capacitance, improves signal integrity for high-speed data paths, and cuts layout time by ~40% versus center-input SOIC alternatives. TI's SCAS049C datasheet explicitly cites this as an optimization for "PCB layout" in the first paragraph of the device description.
Can the 74AC11257PW be used in place of the 74AC157 in existing designs?
No - the 74AC11257PW is not a drop-in replacement for the 74AC157. While both are quad 2:1 multiplexers, the 74AC157 uses individual select inputs (S1–S4) and has 16 pins, whereas the 74AC11257PW uses a single A/B select line and 20-pin TSSOP packaging. Pin count, pinout, and control logic differ fundamentally; redesign of both schematic and layout is required. This distinction is clearly shown in the "FUNCTION TABLE" and "LOGIC DIAGRAM" sections of the 74AC11257PW datasheet.
What is the thermal performance of the 74AC11257PW in continuous operation at 85°C ambient?
The 74AC11257PW has a package thermal impedance θJA of 83°C/W (TSSOP-PW), meaning a 100 mW power dissipation results in ~8.3°C junction-to-ambient rise above ambient. At TA = 85°C, worst-case TJ ≈ 93.3°C - well below the 125°C maximum rating. This margin enables reliable continuous operation in industrial enclosures without forced airflow, as validated by TI's "Absolute Maximum Ratings" and "Operating Characteristics" data in the 74AC11257PW datasheet.
74AC11257PW Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74AC
- Package/Case:
- 20-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Bulk
- Product Status:
- Active
- Type:
- Multiplexer
- Circuit:
- 4 x 2:1
- Independent Circuits:
- 1
- Current - Output High, Low:
- 24mA, 24mA
- Voltage Supply Source:
- Dual Supply
- Voltage - Supply:
- 3V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-TSSOP
74AC11257PW FAQ
1.How can I place an order for 74AC11257PW through Aetrix?
Please submit a Request for Quotation (RFQ) for 74AC11257PW 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 74AC11257PW reliable?
The price and inventory of 74AC11257PW are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 74AC11257PW is usually 5 days.
3.What payment methods are accepted for 74AC11257PW?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 74AC11257PW transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 74AC11257PW?
74AC11257PW orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 74AC11257PW 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 74AC11257PW?
For technical support, including 74AC11257PW datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 74AC11257PW requirements.
6.How does Aetrix verify that 74AC11257PW is sourced from the original manufacturer or authorized distributors?
All 74AC11257PW 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 74AC11257PW meets industry standards.
7.What is the process for return or replacement of 74AC11257PW?
All 74AC11257PW units undergo pre-shipment inspection (PSI). If there is an issue with 74AC11257PW, 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 74AC11257PW part is unused and in its original packaging.
Return procedure for 74AC11257PW:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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