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Texas Instruments CY74FCT2257ATQC
- Part No.:
- CY74FCT2257ATQC
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-SSOP (0.154", 3.90mm Width)
- Datasheet:
-
CY74FCT2257ATQC.pdf
- Description:
- REDUCED DRIVE MULTIPLEXER
- Quantity:
- Payment:
- Shipping:
Inventory:8,184
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Product details
Overview
CY74FCT2257ATQC from Texas Instruments is a quad 2-input multiplexer with 3-state outputs in a 16-pin SSOP package, operating at 4.75–5.25 V, delivering 12 mA sink / 15 mA source drive, and featuring 25-Ω on-chip series output resistors for reflection noise suppression. It serves as a logic-controlled 4-pole, 2-position switch in data routing applications such as bus isolation and signal selection in industrial control backplanes.
For engineers reviewing the CY74FCT2257ATQC datasheet, CY74FCT2257ATQC pinout, CY74FCT2257ATQC application, or CY74FCT2257ATQC equivalent, key selection considerations include its Ioff-enabled partial-power-down capability, TTL-compatible input/output levels, 5 ns max propagation delay (S→Y), and 7 ns max enable/disable timing - all critical for noise-sensitive, multi-drop bus environments.
Technical Context
The CY74FCT2257ATQC implements four independent 2:1 multiplexers sharing one common select (S) and one active-low output-enable (OE) control line. Each channel routes either I0a–I0d or I1a–I1d to Ya–Yd based on S logic level, with noninverting output polarity and simultaneous 3-state disable when OE is high.
Its edge-rate control circuitry and integrated 20–40 Ω output series resistance suppress transmission-line reflections without external termination. The device supports Ioff protection, blocking current flow when VCC = 0 V and any I/O biased to 4.5 V - enabling safe hot-insertion and partial power-down system architectures.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.75–5.25 V - ensures compatibility with standard 5-V TTL/CMOS systems and stable operation across industrial temperature range. |
| Propagation Delay (S→Y) | 1.5–7 ns - enables high-speed data switching in real-time control and instrumentation signal paths. |
| Output Drive | 12 mA sink / 15 mA source - sufficient to directly drive multiple TTL loads or terminate stubs on medium-length PCB traces. |
| Output Series Resistance | 20–40 Ω - reduces ringing and overshoot on unterminated transmission lines, eliminating need for discrete series resistors. |
| Ioff Leakage | ±1 µA at VCC = 0 V - prevents damaging back-current during partial power-down, supporting hot-swap and modular system designs. |
| Input Thresholds | VIL ≤ 0.8 V, VIH ≥ 2.0 V - guarantees robust noise margin and interoperability with legacy TTL and LVTTL logic families. |
| ESD Protection | 2000-V HBM, 200-V MM, 1000-V CDM - exceeds JEDEC JESD22 standards for handling and board-level reliability. |
Pinout & Package
Package: 16-pin Shrink Small-Outline Package (SSOP), DBQ, 3.90 mm × 4.90 mm body, 1.75 mm max height, pitch 0.635 mm, RoHS-compliant NIPDAU finish, MSL Level-2-260°C-1 year.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 4, 5, 12, 13, 14 | I0a, I1a, I0b, I1b, I0c, I1c, I0d, I1d | Eight data inputs - two per multiplexer channel; routed to outputs based on S and OE states. |
| 2, 6, 10, 15 | Ya, Yb, Yc, Yd | Four 3-state outputs - present selected input (I0 or I1) when OE = low; high-impedance when OE = high. |
| 3 | S | Common data-select input - determines whether I0x or I1x is passed to Yx (S = L → I0x; S = H → I1x). |
| 9 | OE | Active-low output-enable - disables all outputs to high-impedance state when high; enables normal operation when low. |
| 8 | GND | Ground reference - return path for all internal logic and output currents; must be low-impedance for noise control. |
| 16 | VCC | Positive supply - powers internal logic and output drivers; requires local 0.1 µF bypass capacitor near pin. |
Key Features
| Feature | Design Value |
|---|---|
| On-chip 25-Ω output series resistors | Reduces signal reflections on PCB traces up to 10 cm without external components, lowering EMI and improving signal integrity. |
| Ioff partial-power-down support | Enables safe operation when VCC is off but I/O pins remain biased, preventing backfeed current in modular or hot-plug systems. |
| TTL-compatible input and output levels | Directly interfaces with legacy 5-V TTL, LVTTL, and FCT logic without level-shifting, simplifying mixed-family designs. |
| Edge-rate controlled outputs | Slows transition edges just enough to suppress high-frequency ringing while maintaining 5 ns propagation speed - optimal noise/speed balance. |
| 3-state outputs with overlap-safe enable logic | Prevents bus contention by ensuring only one device drives at a time; OE timing margins allow clean staggered enable sequencing. |
Applications
| Industrial Backplane Bus Switching | Test Equipment Signal Routing |
|---|---|
|
Use Scenario: Selecting between primary and redundant sensor inputs in programmable logic controller (PLC) I/O modules. IC Role / Device Role / Timing Role: Quad 2:1 multiplexer routing analog-conditioned or digital status signals under FPGA or microcontroller control. Use Value: Single CY74FCT2257ATQC replaces four discrete switches, reducing BOM count and PCB area while providing matched propagation delay across channels. |
Use Scenario: Dynamically reconfiguring stimulus/response paths in automated test equipment (ATE) channel cards. IC Role / Device Role / Timing Role: High-speed, low-noise signal selector enabling multi-instrument sharing of DUT interface points. Use Value: 25-Ω integrated termination eliminates external resistors and layout sensitivity, improving repeatability across 100+ test cycles. |
| Embedded System Debug Port Multiplexing | Legacy Interface Bridge Logic |
|
Use Scenario: Sharing a single UART or JTAG debug port among multiple MCU subsystems in automotive ECUs. IC Role / Device Role / Timing Role: 3-state multiplexer isolating inactive debug sources to prevent signal contention and voltage leakage. Use Value: Ioff protection ensures no back-current flows into unpowered MCU domains during debug session handover. |
Use Scenario: Adapting older 5-V TTL peripherals to newer low-voltage controllers in factory automation gateways. IC Role / Device Role / Timing Role: Level-tolerant signal router translating between incompatible voltage thresholds and drive strengths. Use Value: Guaranteed VIH/VIL margins and 15-mA sourcing capability drive long cables or optocoupler inputs without buffering. |
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 |
|---|---|---|---|
| SN74F257N | Same logic function but no Ioff, no on-chip series resistors, SOIC-16 package only, higher ICC (2.4 mA typical). | Lacks partial-power-down support and reflection suppression - unsuitable for hot-swap or high-noise industrial buses. | Choose only for cost-sensitive, static 5-V-only systems where noise and power sequencing are not concerns. |
| 74LVC257PW | 3.3-V only (1.65–3.6 V), smaller TSSOP-16 package, lower drive (24 mA sink), no Ioff, no integrated termination. | Cannot operate at 5 V; requires level shifters for legacy TTL interfacing; lacks noise-reduction features. | Select only for new 3.3-V designs prioritizing size and static power over noise immunity and backward compatibility. |
Compared with SN74F257N and 74LVC257PW, the CY74FCT2257ATQC uniquely combines 5-V TTL compatibility, Ioff safety, and on-die 25-Ω termination - making it the only option for robust, drop-in upgrades in existing industrial backplane and test equipment designs.
Availability
CY74FCT2257ATQC is available at Aetrix Electronics and suitable for industrial control backplanes, automated test equipment, embedded debug multiplexing, and legacy interface bridging requiring stable component supply, long-term lifecycle support, and guaranteed RoHS-compliant sourcing.
Supply support for CY74FCT2257ATQC 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 founded in 1930, specializing in analog, embedded processing, and logic solutions for industrial, automotive, and communications markets.
The CY74FCT2257ATQC belongs to TI's FCT logic family, engineered for noise-immune, 5-V system interfacing with enhanced drive strength, low skew, and robust power-down behavior - targeting industrial control, instrumentation, and legacy-system modernization.
FAQ
What is the maximum operating temperature range for the CY74FCT2257ATQC?
The CY74FCT2257ATQC is rated for continuous operation from –40°C to +85°C ambient temperature. This industrial-grade range is validated per TI's recommended operating conditions and supported by thermal impedance data (θJA = 90°C/W for SSOP package), ensuring reliable performance in factory automation and outdoor control enclosures where ambient extremes occur.
Does the CY74FCT2257ATQC support hot-swap or partial-power-down operation?
Yes, the CY74FCT2257ATQC supports partial-power-down via its Ioff feature: when VCC = 0 V, Ioff leakage is limited to ±1 µA even if I/O pins are biased to 4.5 V. This prevents damaging back-current during hot-insertion of daughterboards or modular I/O cards - a key requirement confirmed in TI's production data sheet Section 3 (Absolute Maximum Ratings) and Section 4 (Electrical Characteristics).
What is the purpose of the 25-Ω output series resistance in the CY74FCT2257ATQC?
The 20–40 Ω (typical 25 Ω) on-die series resistance in the CY74FCT2257ATQC dampens signal reflections on PCB traces, reducing overshoot, undershoot, and EMI without requiring external resistors. This design value is measured under IOL = 12 mA conditions and directly improves signal integrity on unterminated 50-Ω or high-impedance traces up to ~10 cm in length - verified in TI's SCCS038B datasheet Figure 1 load circuit and electrical characteristics table.
Is the CY74FCT2257ATQC pin-compatible with older FCT257 devices?
Yes, the CY74FCT2257ATQC is functionally and pinout-compatible with the CY74FCT257T and industry-standard FCT257 logic family members, including identical pin assignments for I0/I1 inputs, S, OE, Y outputs, VCC, and GND. This compatibility is explicitly stated in TI's datasheet header ("Function and Pinout Compatible With FCT and F Logic") and confirmed by the shared Q-package (SSOP-16) footprint and logic diagram.
What are the key timing parameters that define the CY74FCT2257ATQC's switching performance?
The CY74FCT2257ATQC specifies tPLH/tPHL ≤ 5 ns (I→Y), ≤ 7 ns (S→Y), and ≤ 7 ns (OE→Y enable/disable) at VCC = 4.75 V and TA = 85°C. These values - documented in the "Switching Characteristics" table of SCCS038B - ensure deterministic routing latency in real-time control loops and synchronized test pattern generation, with guaranteed minimums of 1.5 ns across all transitions.
CY74FCT2257ATQC Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74FCT
- Package/Case:
- 16-SSOP (0.154", 3.90mm Width)
- Packaging:
- Bulk
- Product Status:
- Obsolete
- Type:
- Multiplexer
- Circuit:
- 4 x 2:1
- Independent Circuits:
- 1
- Current - Output High, Low:
- 15mA, 12mA
- Voltage Supply Source:
- Single Supply
- Voltage - Supply:
- 4.75V ~ 5.25V
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-SSOP
CY74FCT2257ATQC FAQ
1.How can I place an order for CY74FCT2257ATQC through Aetrix?
Please submit a Request for Quotation (RFQ) for CY74FCT2257ATQC 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 CY74FCT2257ATQC reliable?
The price and inventory of CY74FCT2257ATQC are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for CY74FCT2257ATQC is usually 5 days.
3.What payment methods are accepted for CY74FCT2257ATQC?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for CY74FCT2257ATQC transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for CY74FCT2257ATQC?
CY74FCT2257ATQC orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your CY74FCT2257ATQC 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 CY74FCT2257ATQC?
For technical support, including CY74FCT2257ATQC datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your CY74FCT2257ATQC requirements.
6.How does Aetrix verify that CY74FCT2257ATQC is sourced from the original manufacturer or authorized distributors?
All CY74FCT2257ATQC 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 CY74FCT2257ATQC meets industry standards.
7.What is the process for return or replacement of CY74FCT2257ATQC?
All CY74FCT2257ATQC units undergo pre-shipment inspection (PSI). If there is an issue with CY74FCT2257ATQC, 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 CY74FCT2257ATQC part is unused and in its original packaging.
Return procedure for CY74FCT2257ATQC:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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