My Inquiry
My Account
Renesas 74FCT257ATQG
- Part No.:
- 74FCT257ATQG
- Manufacturer:
- Renesas
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-SSOP (0.154", 3.90mm Width)
- Datasheet:
-
74FCT257ATQG.pdf
- Description:
- IC MULTIPLEXER 4 X 2:1 16QSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,273
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
74FCT257ATQG from Renesas Electronics (formerly IDT) is a fast CMOS quad 2-input multiplexer with 3-state outputs, designed for bus-oriented digital 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 industrial temperature operation (–40°C to +85°C). Used in data routing, address selection, and bus arbitration where low propagation delay (tPLH/tPHL ≤ 5 ns) and power-off disable are required.
For engineers reviewing the 74FCT257ATQG datasheet, 74FCT257ATQG pinout, 74FCT257ATQG application, or 74FCT257ATQG equivalent, key selection criteria include 3-state output enable timing (tPZH/tPHZ ≤ 7 ns), input leakage ≤1 µA max, JEDEC 18 compliance, SOIC/QSOP package compatibility, and industrial-grade reliability for legacy industrial control and instrumentation designs.
Technical Context
The 74FCT257ATQG implements four independent 2:1 multiplexers sharing a common select (S) and active-low output enable (OE) control. Each channel selects between I0x and I1x inputs and drives a non-inverting true-output (Zx) with high-impedance state when OE is asserted.
It uses advanced dual-metal CMOS technology to achieve TTL-compatible voltage thresholds (VIH = 2.0 V min, VIL = 0.8 V max), low quiescent current (ICC ≤ 1 mA), and robust absolute ratings (VTERM = –0.5 V to VCC+0.5 V on I/O pins, TSTG = –65°C to +150°C).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Supply | 5.0 V ±5% - fixed single-rail operation compatible with legacy TTL/CMOS logic families |
| Propagation Delay | tPLH/tPHL ≤ 5 ns - enables high-speed data routing in 25+ MHz synchronous bus systems |
| Output Drive | IOL = 48 mA / IOH = –15 mA - sufficient to drive multiple TTL loads or terminated transmission lines |
| Input Leakage | ≤1 µA max - ensures stable logic levels in high-impedance or low-power standby modes |
| Enable Timing | tPZH/tPHZ ≤ 7 ns - supports rapid bus turnaround in time-critical shared-data-path applications |
| Operating Temp | –40°C to +85°C - qualified for industrial environments without derating or thermal management |
| Package | QSOP-16 - compact surface-mount footprint with 0.635 mm pitch, suitable for dense PCB layouts |
Pinout & Package
74FCT257ATQG is housed in a 16-pin QSOP (Quarter-size Small Outline Package) with 0.635 mm lead pitch and green RoHS-compliant finish. Pin numbering follows standard top-view orientation with Pin 1 marked by a dot or bevel.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (S) | Select Input | Common 2:1 selector for all four channels; HIGH routes I1x, LOW routes I0x |
| 2 (I0A) | Data Input A, Source 0 | First bit of first source data bus; connects to system address/data line 0 |
| 3 (GND) | Ground Reference | Primary return path for all internal logic and output drivers; must be low-impedance |
| 4 (ZB) | Output B | Non-inverting buffered output for channel B; enters high-Z when OE = HIGH |
| 5 (I0B) | Data Input B, Source 0 | Second bit of first source data bus; used in parallel data path selection |
| 6 (I1B) | Data Input B, Source 1 | Second bit of alternate data source; enables dual-bus arbitration per channel |
| 7 (I1A) | Data Input A, Source 1 | First bit of alternate data source; pairs with I0A for full 2:1 mux functionality |
| 8 (OE) | Output Enable (Active LOW) | Global 3-state control; LOW enables outputs, HIGH disables all Zx pins to high-impedance |
| 9 (I0C) | Data Input C, Source 0 | Third bit of primary source; supports 4-bit-wide multiplexing across channels A–D |
| 10 (I1C) | Data Input C, Source 1 | Third bit of secondary source; maintains consistent 4-channel structure |
| 11 (ZC) | Output C | Non-inverting output for channel C; electrically isolated during OE assertion |
| 12 (I0D) | Data Input D, Source 0 | Fourth bit of primary source; completes quad 2:1 data path |
| 13 (I1D) | Data Input D, Source 1 | Fourth bit of secondary source; enables full 4-bit bus switching |
| 14 (ZD) | Output D | Non-inverting output for channel D; shares same timing and drive specs as ZA–ZC |
| 15 (VCC) | Power Supply | +5 V supply for internal logic and output buffers; requires local 0.1 µF decoupling |
| 16 (ZA) | Output A | Non-inverting output for channel A; routed directly from selected input with no inversion |
Key Features
| Feature | Design Value |
|---|---|
| True TTL input/output compatibility | VIH = 2.0 V min and VOH = 2.4 V min at –8 mA ensure seamless interfacing with legacy 5 V TTL systems |
| High-impedance outputs with live-insertion support | Outputs enter high-Z when VCC = 0 V (IOFF ≤ ±1 µA), enabling hot-swap capability in backplane systems |
| Low dynamic power consumption | ICCD ≤ 0.25 mA/MHz - reduces total system power in toggling applications such as address decoding |
| JEDEC Standard 18 compliance | Meets industry-standard AC/DC electrical requirements for interoperability across logic families |
| Industrial temperature qualification | Guaranteed operation from –40°C to +85°C without performance degradation or derating |
Applications
| Bus Arbitration | Address Multiplexing |
|---|---|
Use Scenario: Multiple peripherals share a common data bus; only one may drive at a time. IC Role / Device Role / Timing Role: 3-state quad multiplexer routes selected peripheral data onto the bus under S and OE control. Use Value: Enables deterministic bus ownership with <5 ns propagation delay and <7 ns enable/disable timing. |
Use Scenario: Microcontroller uses time-multiplexed address/data bus (e.g., Intel 8086 AD0–AD15). IC Role / Device Role / Timing Role: Separates lower-address bits from data during demultiplexing phase using S and OE timing. Use Value: Provides reliable level translation and drive strength for latch-enable synchronization. |
| Legacy System Upgrade | Test Equipment Signal Routing |
Use Scenario: Replacing obsolete TTL multiplexers (e.g., SN74LS257) in field-deployed controllers. IC Role / Device Role / Timing Role: Pin-compatible drop-in replacement with identical function table and DC characteristics. Use Value: Eliminates redesign effort while improving drive capability and reducing power vs. LS-TTL. |
Use Scenario: Automated test equipment selects between calibration references, DUT signals, or stimulus sources. IC Role / Device Role / Timing Role: Quad 2:1 switch routes four independent analog/digital signal paths under microcontroller control. Use Value: Supports simultaneous multi-channel routing with guaranteed 48 mA sink capability per output. |
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 |
|---|---|---|---|
| 74FCT257CTQG | Same architecture and pinout; rated for –40°C to +85°C but with tighter tPLH/tPHL max = 4.3 ns | Suitable for higher-speed timing-critical paths where sub-5 ns delay is mandatory | Select 74FCT257CTQG when propagation delay budget is constrained below 5 ns; otherwise 74FCT257ATQG offers cost-optimized performance. |
| 74FCT257DTQG | Same architecture and pinout; rated for –40°C to +85°C with tightest timing: tPLH/tPHL max = 3.9 ns | Used in highest-performance legacy industrial controllers requiring minimal skew across all four channels | Choose 74FCT257DTQG only if system-level timing analysis confirms need for ≤3.9 ns delay; verify thermal margin at full load. |
Compared with 74FCT257CTQG and 74FCT257DTQG, the 74FCT257ATQG provides the most cost-effective balance of industrial temperature range, 3-state control, and verified 5 ns timing margin-ideal for volume production where marginal speed gain does not justify premium grade cost.
Availability
74FCT257ATQG is available at Aetrix Electronics and suitable for industrial control panels, legacy instrumentation interfaces, and bus-based embedded systems requiring stable component supply and long-term obsolescence mitigation.
Supply support for 74FCT257ATQG 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 74FCT257ATQG belongs to Renesas' legacy FCT logic family, engineered for pin-compatible upgrades of TTL devices in industrial and telecom infrastructure where reliability, noise immunity, and 5 V compatibility remain essential.
FAQ
Is the 74FCT257ATQG still in production or considered obsolete?
The 74FCT257ATQG is marked obsolete by Renesas per datasheet revision dated September 2019. However, Aetrix Electronics maintains active inventory and extended supply chain access for this part to support legacy industrial system maintenance and repair. No new design-in is recommended, but existing designs may continue sourcing through authorized channels with full traceability.
What is the maximum clock/data toggle frequency supported by the 74FCT257ATQG?
The 74FCT257ATQG does not operate as a clocked device-it is asynchronous. Its usable data rate depends on propagation delay and system setup/hold timing. With tPLH/tPHL ≤ 5 ns and tPZH/tPHZ ≤ 7 ns, it reliably supports bus cycles up to ~25 MHz in well-terminated, low-skew PCB layouts. Dynamic current (ICCD) is specified up to 10 MHz for power estimation.
Does the 74FCT257ATQG support mixed-voltage operation (e.g., 3.3 V inputs with 5 V VCC)?
No. The 74FCT257ATQG is a 5 V-only device. Inputs must remain within VIH ≥ 2.0 V and VIL ≤ 0.8 V referenced to its 5 V VCC rail. Applying 3.3 V logic levels directly risks marginal VIH recognition and is not guaranteed per datasheet specifications. Level-shifting circuitry is required for interfacing with 3.3 V systems.
Can the 74FCT257ATQG outputs drive a 50 Ω transmission line?
Yes-the 74FCT257ATQG delivers 48 mA sink current (IOL), sufficient to drive a properly terminated 50 Ω line to ≤0.5 V (VOL max). For clean signal integrity, use series termination near the driver and maintain controlled impedance routing. Avoid unterminated stubs longer than 1 inch to prevent reflections.
What is the meaning of "power off disable outputs" in the 74FCT257ATQG datasheet?
"Power off disable outputs" means that when VCC = 0 V, all outputs (ZA–ZD) enter high-impedance state with leakage ≤±1 µA (IOFF), even if input signals remain active. This prevents back-driving powered-down sections of a system and enables safe live insertion into backplanes or hot-swap modules-critical in modular industrial hardware.
74FCT257ATQG Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Renesas
- Series:
- 74FCT
- Package/Case:
- 16-SSOP (0.154", 3.90mm Width)
- Packaging:
- Tube
- 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
74FCT257ATQG FAQ
1.How can I place an order for 74FCT257ATQG through Aetrix?
Please submit a Request for Quotation (RFQ) for 74FCT257ATQG 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 74FCT257ATQG reliable?
The price and inventory of 74FCT257ATQG are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 74FCT257ATQG is usually 5 days.
3.What payment methods are accepted for 74FCT257ATQG?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 74FCT257ATQG transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 74FCT257ATQG?
74FCT257ATQG orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 74FCT257ATQG 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 74FCT257ATQG?
For technical support, including 74FCT257ATQG datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 74FCT257ATQG requirements.
6.How does Aetrix verify that 74FCT257ATQG is sourced from the original manufacturer or authorized distributors?
All 74FCT257ATQG 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 74FCT257ATQG meets industry standards.
7.What is the process for return or replacement of 74FCT257ATQG?
All 74FCT257ATQG units undergo pre-shipment inspection (PSI). If there is an issue with 74FCT257ATQG, 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 74FCT257ATQG part is unused and in its original packaging.
Return procedure for 74FCT257ATQG:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
74FCT257ATQG Tags
-
SN74HC138DR
Texas Instruments
-
TC7SB3157CFU,LF(CT
Toshiba Semiconductor and Storage
-
74CBTLV3257PW,118
Nexperia USA Inc.
-
SN74CBTLV3257PWR
Texas Instruments
-
74CBTLV3257GUX
Nexperia USA Inc.
-
74HC154BQ,118
Nexperia USA Inc.
-
P3S0200GMX
NXP USA Inc.
-
SN74CB3Q3245PWR
Texas Instruments
-
SN74CB3Q3257RGYR
Texas Instruments
-
TCA9543APWR
Texas Instruments
-
TCA9546APWR
Texas Instruments
-
SN74HC138N
Texas Instruments
Tech Hub
TTL and CMOS logic families differ in thresholds, loading, output drive, power and timing. This engineering guide compares 74HC and 74HCT, calculates noise margins and checks 3.3 V/5 V compatibility.
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
