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STMicroelectronics 74LCX257TTR
- Part No.:
- 74LCX257TTR
- Manufacturer:
- STMicroelectronics
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
74LCX257TTR.pdf
- Description:
- IC MULTIPLEXER 4 X 2:1 16TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,675
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Product details
Overview
74LCX257TTR from STMicroelectronics is a low-voltage CMOS quad 2-channel multiplexer with 3-state outputs, 5V-tolerant I/O, and pin/function compatibility with standard 74-series 257 devices. It operates from 2.0V to 3.6V, delivers 6.0 ns max propagation delay at 3V, supports ±24 mA output drive, and features symmetrical output impedance and power-down protection on all I/O pins. It is used in voltage-level-translating data routing for 3.3V/5V mixed-signal systems.
For engineers reviewing the 74LCX257TTR datasheet, 74LCX257TTR pinout, 74LCX257TTR application, or 74LCX257TTR equivalent, key selection criteria include 5V-tolerant input/output capability, 3.3V-compatible propagation delay, high-impedance output control via active-low OE, and guaranteed PCI bus levels at 24 mA drive strength.
Technical Context
The 74LCX257TTR implements four independent non-inverting 2:1 multiplexers sharing common SELECT and active-low ENABLE (OE) inputs. Each channel selects between A and B inputs based on the logic level of SELECT, with outputs entering high-impedance state when OE is HIGH.
Its C2MOS sub-micron fabrication enables rail-to-rail 5V-tolerant I/O while operating from 2.0–3.6V VCC, delivering balanced tPLH/tPHL delays and latch-up immunity exceeding 500 mA per JESD17. Input and output protection circuits provide >2000V HBM ESD robustness.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Operating Range | 2.0 V to 3.6 V - Enables direct integration into 3.3V logic domains with 1.5V data retention during standby |
| tPD (Max) | 6.0 ns at VCC = 3V - Matches AC/ACT family speed at lower supply voltage, supporting high-throughput data switching |
| IOL / IOH (Min) | ±24 mA at VCC = 3.0–3.6V - Drives PCI-compliant loads without external buffers |
| Input Voltage Range | −0.5 V to +7.0 V - Supports 5V-tolerant operation across all inputs and outputs, enabling mixed-voltage interfacing |
| Output Enable Polarity | Active LOW (OE) - Allows synchronous disable of all four outputs using a single control signal |
| Propagation Skew (Max) | 1.0 ns - Ensures tightly aligned timing across all four Y outputs for parallel data paths |
Pinout & Package
TSSOP-16 package (JEDEC MO-153, 4.4 mm × 5.0 mm body, 0.65 mm pitch), lead-free and RoHS-compliant.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | SELECT | Common control input determining whether A or B data is routed to each Y output |
| 2,5,11,14 | 1A–4A | Four independent data inputs from source A side of multiplexer |
| 3,6,10,13 | 1B–4B | Four independent data inputs from source B side of multiplexer |
| 4,7,9,12 | 1Y–4Y | Four 3-state outputs, each driven by corresponding A/B selection and OE state |
| 15 | OE | Active-low output enable controlling high-impedance state for all Y outputs simultaneously |
| 8 | GND | Reference ground terminal for logic and power integrity |
| 16 | VCC | Primary supply voltage pin (2.0–3.6V); powers internal logic and output drivers |
Key Features
| Feature | Design Value |
|---|---|
| 5V-tolerant I/O | Supports direct connection to 5V buses without level shifters in mixed-voltage systems |
| Symmetrical output drive | |IOH| = IOL ≥ 24 mA ensures matched rise/fall times and reduced signal distortion |
| Power-down protection | Prevents current backflow and latch-up during power sequencing or partial system shutdown |
| Low dynamic power consumption | CPD = 25 pF enables efficient operation at high frequencies with minimal ICC(opr) increase |
Applications
| PCI Bus Interface | 3.3V/5V Level Translation |
|---|---|
Use Scenario: Routing address/data signals between 3.3V host controller and legacy 5V peripheral cards in PCI add-in slots. IC Role / Device Role / Timing Role: Quad 2:1 multiplexer selecting between native 3.3V and translated 5V signal paths under SELECT and OE control. Use Value: Eliminates discrete level shifters while meeting PCI electrical specs for 24 mA drive and skew-critical timing alignment. | Use Scenario: Bidirectional signal translation in embedded systems with mixed 3.3V FPGA I/O banks and 5V sensor/actuator interfaces. IC Role / Device Role / Timing Role: Voltage-agnostic data selector enabling safe, high-speed handshaking across supply domains. Use Value: Maintains signal integrity with <6 ns propagation delay and <1 ns inter-output skew, avoiding timing violations. |
| Memory Address Multiplexing | Configurable Data Path Switching |
Use Scenario: Selecting between two memory banks (e.g., SRAM vs. Flash) sharing a common data bus in low-power microcontroller subsystems. IC Role / Device Role / Timing Role: Non-inverting multiplexer providing glitch-free address/data routing with simultaneous 3-state control via OE. Use Value: Reduces board space versus discrete solutions and ensures deterministic high-Z isolation during bank switching. | Use Scenario: Reconfiguring test instrumentation signal paths (e.g., oscilloscope inputs, logic analyzer channels) via software-controlled SELECT/OE. IC Role / Device Role / Timing Role: Hardware-selectable signal router enabling flexible front-end signal conditioning and routing. Use Value: Delivers consistent 24 mA drive and <0.55 V VOL at full load, ensuring reliable TTL/CMOS compatibility across configurations. |
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 |
|---|---|---|---|
| 74LVC257PW | Lower VCC range (1.65–3.6V); 5V-tolerant inputs only (not outputs); 32 mA drive at 3.3V | Not suitable for bidirectional 5V bus driving; requires external pull-ups for open-drain compatibility | Preferred where ultra-low static current (<1 µA) and smaller TSSOP-14 footprint are prioritized over 5V output tolerance |
| SN74LVCH257AQPWRQ1 | Automotive-grade (AEC-Q100); same 2.0–3.6V range; 5V-tolerant I/O; higher ESD rating (4 kV HBM) | Qualified for automotive infotainment and ADAS domain controllers requiring extended temperature and reliability validation | Select when functional safety compliance (ISO 26262 support) and −40°C to +125°C operation are mandatory |
Compared with 74LCX257TTR, the 74LVC257PW offers higher drive but lacks 5V-tolerant outputs, limiting its use in true bidirectional 5V environments; the SN74LVCH257AQPWRQ1 adds automotive qualification and enhanced ESD robustness at no speed penalty, making it ideal for mission-critical vehicle systems.
Availability
74LCX257TTR is available at Aetrix Electronics and suitable for PCI interface design, 3.3V/5V level translation, and memory address multiplexing requiring stable component supply and long-term industrial availability.
Supply support for 74LCX257TTR 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
STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, specializing in microcontrollers, analog ICs, power management, and automotive semiconductors.
The 74LCX logic family was designed for high-speed, low-voltage operation in mixed-signal systems requiring 5V-tolerant interoperability - targeting industrial control, communications infrastructure, and legacy bus interface applications.
FAQ
What is the maximum recommended operating temperature for the 74LCX257TTR?
The 74LCX257TTR is rated for continuous operation from −55°C to +125°C ambient temperature, with full DC and AC specifications guaranteed across this range. Its C2MOS process and robust ESD structures ensure stable performance in extended-temperature industrial environments without derating.
Can the 74LCX257TTR safely drive a 50 Ω transmission line directly?
No - while the device drives 24 mA into resistive loads, its output structure is not optimized for 50 Ω line driving. For controlled-impedance traces, use series termination (e.g., 33 Ω resistor near the driver) and verify signal integrity with CL = 50 pF load per datasheet test conditions.
Is the SELECT input internally debounced or does it require external filtering?
The SELECT input has no internal debouncing circuitry. It is a standard CMOS input with typical VIH/VIL thresholds (2.0 V/0.8 V at VCC = 3.0 V). External RC filtering or firmware synchronization is required if driven by mechanical switches or noisy control signals.
Does the 74LCX257TTR support hot insertion in live backplanes?
Yes - its power-down protection on inputs and outputs, combined with 5V-tolerant I/O and high-impedance state activation via OE, enables safe hot-plug operation in modular backplane systems, provided VCC ramp rates comply with recommended limits (≤1 V/ms) and GND connects first.
74LCX257TTR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Series:
- 74LCX
- Package/Case:
- 16-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Type:
- Multiplexer
- Circuit:
- 4 x 2:1
- Independent Circuits:
- 1
- Current - Output High, Low:
- 24mA, 24mA
- Voltage Supply Source:
- Single Supply
- Voltage - Supply:
- 2V ~ 3.6V
- Operating Temperature:
- -55°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-TSSOP
74LCX257TTR FAQ
1.How can I place an order for 74LCX257TTR through Aetrix?
Please submit a Request for Quotation (RFQ) for 74LCX257TTR 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 74LCX257TTR reliable?
The price and inventory of 74LCX257TTR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 74LCX257TTR is usually 5 days.
3.What payment methods are accepted for 74LCX257TTR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 74LCX257TTR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 74LCX257TTR?
74LCX257TTR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 74LCX257TTR 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 74LCX257TTR?
For technical support, including 74LCX257TTR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 74LCX257TTR requirements.
6.How does Aetrix verify that 74LCX257TTR is sourced from the original manufacturer or authorized distributors?
All 74LCX257TTR 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 74LCX257TTR meets industry standards.
7.What is the process for return or replacement of 74LCX257TTR?
All 74LCX257TTR units undergo pre-shipment inspection (PSI). If there is an issue with 74LCX257TTR, 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 74LCX257TTR part is unused and in its original packaging.
Return procedure for 74LCX257TTR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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