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Renesas 74FCT257ATQG8
- Part No.:
- 74FCT257ATQG8
- Manufacturer:
- Renesas
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-SSOP (0.154", 3.90mm Width)
- Datasheet:
-
74FCT257ATQG8.pdf
- Description:
- IC MULTIPLEXER 4 X 2:1 16QSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,139
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Product details
Overview
74FCT257ATQG8 from Renesas Electronics (formerly IDT) is a fast CMOS quad 2-input multiplexer with 3-state outputs, designed for bus-oriented data routing in industrial systems. It features true TTL input/output compatibility (VOH = 3.3 V typ., VOL = 0.3 V typ.), high drive capability (–15 mA IOH, 48 mA IOL), and operates across –40°C to +85°C. Used in address/data bus selection and signal gating applications where low propagation delay (tPLH/tPHL ≤ 5 ns) and power-off safe insertion are required.
For engineers reviewing the 74FCT257ATQG8 datasheet, 74FCT257ATQG8 pinout, 74FCT257ATQG8 application, or 74FCT257ATQG8 equivalent, key selection criteria include its industrial temperature rating, 3-state output enable control, dual-source data selection per channel, and SOIC-16/QSOP-16 package compatibility with legacy FCT logic families.
Technical Context
The 74FCT257ATQG8 implements four independent 2:1 multiplexers sharing a common select (S) and active-low output enable (OE) input. Each channel selects between I0x and I1x inputs, driving true (non-inverting) outputs ZA–ZD with CMOS-level switching and TTL-compatible thresholds.
Its advanced dual-metal CMOS process enables fast propagation delays (tPLH/tPHL ≤ 5 ns at CL = 50 pF), low quiescent current (ICC ≤ 1 mA), and robust 3-state behavior - including power-off disable that permits live insertion into powered backplanes without bus contention.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Supply Voltage | 5.0 V ±5% - fixed single-rail operation compatible with standard TTL/CMOS logic domains |
| Propagation Delay (Ix→Zx) | ≤5 ns - ensures sub-200 MHz timing margin in synchronous bus multiplexing |
| Output Drive (IOL/IOH) | 48 mA / –15 mA - directly drives multiple TTL loads or terminates stubs on medium-length PCB traces |
| Input Leakage Current | ≤1 µA max - minimizes static current draw in battery-backed or low-power standby modes |
| Operating Temperature | –40°C to +85°C - validated for industrial control, motor drives, and factory automation environments |
| 3-State Enable Time (tPZH) | ≤7 ns - supports rapid bus arbitration and dynamic reconfiguration in real-time systems |
Pinout & Package
74FCT257ATQG8 is packaged in a 16-pin QSOP (Quarter-size Small Outline Package) with 0.65 mm pitch, JEDEC MO-137 compliant, footprint-compatible with SOIC-16 but with reduced body width (3.9 mm vs. 7.5 mm).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (S) | Select Input | Common control for all four multiplexers: S = LOW selects I0x, S = HIGH selects I1x |
| 2 (I0A) | Data Input A, Source 0 | First bit of first data source; routed to ZA when S = LOW |
| 3 (GND) | Ground Reference | Primary return path for all internal logic and output drivers |
| 4 (ZB) | Output B | True (non-inverting) output for channel B; high-impedance when OE = HIGH |
| 5 (I0B) | Data Input B, Source 0 | Second bit of first data source; routed to ZB when S = LOW |
| 6 (I1B) | Data Input B, Source 1 | Second bit of second data source; routed to ZB when S = HIGH |
| 7 (I1A) | Data Input A, Source 1 | First bit of second data source; routed to ZA when S = HIGH |
| 8 (OE) | Output Enable (Active LOW) | Global 3-state control: OE = LOW enables outputs; OE = HIGH forces ZA–ZD into high-Z |
| 9 (I0C) | Data Input C, Source 0 | Third bit of first data source; routed to ZC when S = LOW |
| 10 (I1C) | Data Input C, Source 1 | Third bit of second data source; routed to ZC when S = HIGH |
| 11 (ZC) | Output C | True output for channel C; high-impedance when OE = HIGH |
| 12 (I0D) | Data Input D, Source 0 | Fourth bit of first data source; routed to ZD when S = LOW |
| 13 (I1D) | Data Input D, Source 1 | Fourth bit of second data source; routed to ZD when S = HIGH |
| 14 (ZD) | Output D | True output for channel D; high-impedance when OE = HIGH |
| 15 (VCC) | Positive Supply | +5 V power rail; decoupling capacitor required within 1 cm of this pin |
| 16 (ZA) | Output A | True output for channel A; high-impedance when OE = HIGH |
Key Features
| Feature | Design Value |
|---|---|
| TTL-compatible input thresholds | VIH = 2.0 V min, VIL = 0.8 V max - interoperates directly with legacy 74LS/74ALS without level-shifting |
| Live-insertion support | Power-off disable outputs (IOFF ≤ ±1 µA at VCC = 0 V) - prevents back-driving during hot-swap operations |
| High noise immunity | Input hysteresis ≥200 mV - suppresses false triggering on noisy industrial control lines |
| Low dynamic power consumption | ICCD ≤ 0.25 mA/MHz - reduces thermal load in dense logic arrays and fan-out-heavy designs |
| JEDEC Std. 18 compliance | Fully conforms to registered interface standards for 3-state CMOS bus devices - ensures system-level interoperability |
Applications
| Industrial PLC Backplane Multiplexing | Legacy Bus Interface Translation |
|---|---|
|
Use Scenario: Routing address/data signals between CPU and multiple I/O modules on a shared 8-bit or 16-bit backplane. IC Role / Device Role / Timing Role: Quad 2:1 multiplexer enabling dynamic selection of peripheral banks under microcontroller control. Use Value: Eliminates need for discrete logic gates or larger CPLDs while maintaining <5 ns propagation delay for cycle-accurate timing. |
Use Scenario: Interfacing modern microcontrollers with older TTL-based peripherals requiring strict VIH/VIL levels. IC Role / Device Role / Timing Role: Level-translating bus switch providing bidirectional signal integrity and 3-state isolation. Use Value: Enables direct connection without external pull-ups or Schmitt triggers due to guaranteed TTL-compatible thresholds and 48 mA sink capability. |
| Motor Control Signal Gating | Test Equipment Signal Routing |
|
Use Scenario: Selecting between primary and redundant encoder feedback paths in servo amplifier designs. IC Role / Device Role / Timing Role: Fault-tolerant signal selector with fail-safe high-impedance state during OE assertion. Use Value: Supports safe shutdown and diagnostics via OE control, with leakage <1 µA ensuring no unintended current flow during fault conditions. |
Use Scenario: Automated test fixtures requiring flexible routing of stimulus and response signals across multiple DUT channels. IC Role / Device Role / Timing Role: Reconfigurable signal path controller synchronized to test sequencer clocks. Use Value: Sub-5 ns delay and precise setup/hold timing allow deterministic signal switching at up to 100 MHz test clock rates. |
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 |
|---|---|---|---|
| 74FCT257CTQG8 | Same function and pinout; rated for –40°C to +85°C but with tighter tPLH/tPHL max (4.3 ns vs. 5 ns) and lower ICC (0.5 mA typ.) | Better suited for high-speed timing-critical paths where <4.5 ns delay is mandatory | Select 74FCT257CTQG8 when propagation delay budget is constrained below 5 ns; otherwise 74FCT257ATQG8 offers cost-effective industrial-grade performance. |
| SN74F257N | 74F-family TTL part in PDIP-16; higher ICC (15 mA typ.), slower delay (11 ns), no power-off disable | Limited to non-hot-swap, low-density board designs with ample power budget | Choose SN74F257N only for legacy repair or prototyping where through-hole mounting and TTL-only compatibility are required. |
Compared with 74FCT257CTQG8 and SN74F257N, the 74FCT257ATQG8 delivers optimal balance of speed, power efficiency, and live-insertion safety - making it preferred for new industrial designs needing reliable 3-state bus management without over-specifying performance.
Availability
74FCT257ATQG8 is available at Aetrix Electronics and suitable for industrial PLC backplane multiplexing, legacy bus interface translation, and motor control signal gating requiring stable component supply and long-term lifecycle support.
Supply support for 74FCT257ATQG8 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
Renesas Electronics Corporation is a global semiconductor leader delivering microcontrollers, analog, power, and SoC solutions for automotive, industrial, infrastructure, and IoT applications.
The 74FCT257ATQG8 belongs to Renesas' legacy FCT logic family, engineered for high-speed, low-power, TTL-compatible bus interfacing in industrial control and instrumentation systems.
FAQ
What is the operating voltage range for the 74FCT257ATQG8?
The 74FCT257ATQG8 operates at a nominal VCC of 5.0 V with a tolerance of ±5%, meaning the valid supply range is 4.75 V to 5.25 V. This specification is strictly defined for industrial temperature operation (–40°C to +85°C) and must be maintained to guarantee VOH ≥ 2.4 V, VOL ≤ 0.5 V, and timing parameters per datasheet.
Does the 74FCT257ATQG8 support live insertion into a powered system?
Yes, the 74FCT257ATQG8 supports live insertion due to its power-off disable feature: when VCC = 0 V, input/output leakage remains ≤ ±1 µA, preventing back-driving of live buses. This behavior is verified per JEDEC Std. 18 and confirmed in the Absolute Maximum Ratings table for IOFF under VCC = 0 V conditions.
What is the maximum output drive capability of the 74FCT257ATQG8?
The 74FCT257ATQG8 provides 48 mA sink current (IOL) and –15 mA source current (IOH) per output, measured at VCC = 4.75 V, TA = +85°C. These values ensure robust driving of multiple TTL loads or termination of unterminated traces up to ~10 cm on FR-4 PCBs without signal degradation.
Is the 74FCT257ATQG8 pin-compatible with other members of the FCT257 family?
Yes, the 74FCT257ATQG8 shares identical pinout and function with 74FCT257CTQG8 and 74FCT257DTQG8 - differing only in speed grade and ICC specifications. All three use the same QSOP-16 package and support identical logic behavior, select timing, and 3-state control sequences.
What does "NOT RECOMMENDED FOR NEW DESIGNS" mean for the 74FCT257ATQG8?
"NOT RECOMMENDED FOR NEW DESIGNS" indicates Renesas has classified the 74FCT257ATQG8 as obsolete per PDN# CQ-15-04 (2015) and updated datasheet status (2019). However, Aetrix Electronics maintains active inventory and supply chain support, ensuring continued availability for maintenance, replacement, and legacy production runs.
74FCT257ATQG8 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Renesas
- Series:
- 74FCT
- Package/Case:
- 16-SSOP (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Type:
- Multiplexer
- Circuit:
- 4 x 2:1
- Independent Circuits:
- 1
- Current - Output High, Low:
- 15mA, 48mA
- Voltage Supply Source:
- Single Supply
- Voltage - Supply:
- -
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-QSOP
74FCT257ATQG8 FAQ
1.How can I place an order for 74FCT257ATQG8 through Aetrix?
Please submit a Request for Quotation (RFQ) for 74FCT257ATQG8 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 74FCT257ATQG8 reliable?
The price and inventory of 74FCT257ATQG8 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 74FCT257ATQG8 is usually 5 days.
3.What payment methods are accepted for 74FCT257ATQG8?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 74FCT257ATQG8 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 74FCT257ATQG8?
74FCT257ATQG8 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 74FCT257ATQG8 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 74FCT257ATQG8?
For technical support, including 74FCT257ATQG8 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 74FCT257ATQG8 requirements.
6.How does Aetrix verify that 74FCT257ATQG8 is sourced from the original manufacturer or authorized distributors?
All 74FCT257ATQG8 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 74FCT257ATQG8 meets industry standards.
7.What is the process for return or replacement of 74FCT257ATQG8?
All 74FCT257ATQG8 units undergo pre-shipment inspection (PSI). If there is an issue with 74FCT257ATQG8, 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 74FCT257ATQG8 part is unused and in its original packaging.
Return procedure for 74FCT257ATQG8:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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