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STMicroelectronics 74VHCT257ATTR
- Part No.:
- 74VHCT257ATTR
- Manufacturer:
- STMicroelectronics
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
74VHCT257ATTR.pdf
- Description:
- IC MULTIPLEXER 4 X 2:1 16TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,415
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Product details
Overview
74VHCT257ATTR from STMicroelectronics is a quad 2-channel non-inverting multiplexer with 3-state outputs, designed for high-speed digital signal routing in 5V TTL-compatible systems. It features 4.8 ns typical propagation delay at 5V, ±8 mA symmetrical output drive, and operates across 4.5–5.5V supply range. Its pin- and function-compatible replacement for 74LS257 enables drop-in upgrades in bus-multiplexing and data-path selection applications.
For engineers reviewing the 74VHCT257ATTR datasheet, 74VHCT257ATTR pinout, 74VHCT257ATTR application, or 74VHCT257ATTR equivalent, key selection criteria include guaranteed 3-state output disable timing (tPZL/tPLZ ≤ 8.0 ns), input tolerance up to 7V independent of VCC, and 2 kV HBM ESD immunity on all I/O pins - critical for mixed-voltage interface and hot-swap robustness.
Technical Context
The device implements four independent 2:1 multiplexers sharing common SELECT and active-low ENABLE (OE) inputs, enabling simultaneous channel selection and global output tri-state control. All inputs accept TTL-level thresholds (VIH ≥ 2.0 V, VIL ≤ 0.8 V), allowing direct interfacing with legacy 5V TTL logic without level shifters.
Its C2MOS fabrication ensures low static current (ICC ≤ 4 µA at 25°C) and improved latch-up immunity, while power-down protection permits safe operation with input voltages from 0 to 7 V regardless of VCC state - essential for partial-power-down system architectures and I²C/SPI bus isolation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Propagation Delay (tPD) | 4.8 ns typ. at VCC = 5V, CL = 15 pF - enables reliable operation in >100 MHz data paths with margin. |
| Supply Voltage Range | 4.5 V to 5.5 V - supports industrial-grade 5V rail tolerance and brown-out resilience. |
| Output Drive Strength | |IOH| = |IOL| = 8 mA min. - drives standard TTL loads and short PCB traces without buffering. |
| Input Voltage Tolerance | 0 V to 7 V independent of VCC - allows safe interfacing with 3.3V/5V mixed-signal domains. |
| ESD Immunity | 2 kV HBM - meets IEC 61000-4-2 Level 2 for board-level transient robustness. |
| Quiescent Current | ICC = 4 µA max. at TA = 25°C - minimizes standby power in battery-backed or always-on modules. |
Pinout & Package
TSSOP-16 package: 4.4 mm × 5.0 mm body, 0.65 mm pitch, 1.2 mm height, lead-free and RoHS-compliant.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | SELECT | Common 2:1 channel select input; low = A-input selected, high = B-input selected. |
| 2,5,11,14 | 1A–4A | Data inputs from source A; each routed independently to corresponding Y output when SELECT = low. |
| 3,6,10,13 | 1B–4B | Data inputs from source B; each routed independently to corresponding Y output when SELECT = high. |
| 4,7,9,12 | 1Y–4Y | 3-state multiplexer outputs; high-impedance when OE = high or during disable transitions. |
| 15 | OE | Active-low output enable; asserts all Y outputs to high-Z when high, enables normal operation when low. |
| 8 | GND | Digital ground reference for logic thresholds and current return path. |
| 16 | VCC | Positive supply input; powers internal logic and output drivers; must be decoupled locally. |
Key Features
| Feature | Design Value |
|---|---|
| Pin- and function-compatible with 74LS257 | Enables direct replacement in legacy designs without PCB or firmware changes. |
| Symmetrical output impedance | Ensures matched rise/fall times (tPLH ≅ tPHL), reducing signal skew in parallel data buses. |
| Power-down protection on all I/O | Permits safe operation with floating or overvoltage inputs during power sequencing or sleep modes. |
| Low dynamic noise (VOLP ≤ 0.8 V) | Minimizes ground bounce and crosstalk in dense digital layouts with shared supply/ground planes. |
Applications
| Industrial PLC I/O Expansion | Automotive Body Control Module |
|---|---|
Use Scenario: Multiplexing multiple sensor inputs (e.g., door switches, seat occupancy) onto a single microcontroller ADC or GPIO port. IC Role / Device Role / Timing Role: Quad 2:1 analog/digital signal selector with 3-state isolation between measurement cycles. Use Value: Reduces MCU pin count by 4× while maintaining <8 ns output disable time for fast channel switching and noise isolation. | Use Scenario: Routing diagnostic signals (CAN status, LIN wake-up, lamp test pulses) between ECUs and shared test interfaces. IC Role / Device Role / Timing Role: Bidirectional signal gate controlled by microcontroller GPIO to isolate fault-prone subsystems. Use Value: 7V-tolerant inputs prevent latch-up during battery transients; 2 kV ESD rating withstands vehicle-level ESD events. |
| Legacy System Bus Interface | Test Equipment Signal Routing |
Use Scenario: Interfacing modern 5V FPGA I/O banks with legacy TTL peripherals (e.g., EPROMs, parallel printers) via shared data bus. IC Role / Device Role / Timing Role: Level-shifting multiplexer enabling bidirectional data flow with tristate arbitration. Use Value: TTL-compatible inputs eliminate external level shifters; 4.8 ns tPD supports 100+ MHz bus clocking. | Use Scenario: Automated test fixture selecting between multiple DUT signal sources (clock, trigger, stimulus) before feeding to measurement instruments. IC Role / Device Role / Timing Role: Precision-controlled signal path selector with deterministic enable/disable timing. Use Value: Guaranteed tPZL/tPLZ ≤ 8.0 ns ensures repeatable signal edge alignment across channels for jitter-sensitive measurements. |
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 |
|---|---|---|---|
| SN74VHC257DR | Higher VCC range (2–5.5 V); lower ICC (1 µA typ.); no 7V input tolerance. | Preferred for dual-supply or battery-powered 3.3V systems; unsuitable for 5V-only mixed-voltage hot-swap. | Select when operating below 4.5 V or requiring ultra-low quiescent current; verify input voltage limits match system rails. |
| 74LCX257MTCX | 3.3V-only operation (2.7–3.6 V); higher speed (tPD = 3.5 ns); 5V-tolerant inputs only. | Optimized for high-speed 3.3V logic families; requires external level translation for 5V interface. | Choose for 3.3V-native designs needing sub-4 ns delay; avoid where 5V signal integrity or mixed-rail tolerance is required. |
Compared with SN74VHC257DR and 74LCX257MTCX, the 74VHCT257ATTR uniquely balances 5V TTL compatibility, 7V input tolerance, and industrial temperature support (–55°C to +125°C), making it the only option qualified for automotive and harsh-environment 5V bus multiplexing without external protection.
Availability
74VHCT257ATTR is available at Aetrix Electronics and suitable for industrial PLC I/O expansion, automotive body control modules, and legacy system bus interface applications requiring stable component supply and long-term lifecycle assurance.
Supply support for 74VHCT257ATTR 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 automotive, industrial, and power management ICs with vertical manufacturing capability and AEC-Q100 qualification expertise.
The VHCT logic family targets high-speed, low-power 5V TTL-compatible digital interface applications, emphasizing robustness in mixed-voltage systems, ESD resilience, and seamless migration from legacy bipolar logic.
FAQ
Can the 74VHCT257ATTR operate with a 3.3V supply?
No. The device is specified only for 4.5–5.5V operation per Table 5. At 3.3V, VIH/VIL thresholds are not met, and output drive falls outside specification. For 3.3V systems, consider SN74VHC257 or 74LCX257 instead.
What happens if an input exceeds VCC by more than 0.5V?
Inputs tolerate 0–7V regardless of VCC value due to built-in clamping diodes and power-down protection. This allows safe connection to 5V signals even when VCC is off or at 3.3V - confirmed in Absolute Maximum Ratings (Table 4) and Input Equivalent Circuit (Figure 2).
Is the 74VHCT257ATTR pin-compatible with the 74LS257 in TSSOP package?
Yes. Pin numbering, function mapping, and electrical behavior (including SELECT/OE polarity and 3-state timing) match the 74LS257. The TSSOP-16 footprint aligns with industry-standard 74-series TSSOP layouts, enabling mechanical and logical drop-in replacement.
Does this device support hot-plug insertion into a live 5V bus?
Yes. With 7V input tolerance, 2 kV HBM ESD rating, and power-down protection on all I/O, the 74VHCT257ATTR safely handles live insertion into powered 5V backplanes - provided VCC is ramped before applying input signals, per recommended power sequencing in ST AN2057.
74VHCT257ATTR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Series:
- 74VHCT
- 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:
- 8mA, 8mA
- Voltage Supply Source:
- Single Supply
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -55°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-TSSOP
74VHCT257ATTR FAQ
1.How can I place an order for 74VHCT257ATTR through Aetrix?
Please submit a Request for Quotation (RFQ) for 74VHCT257ATTR 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 74VHCT257ATTR reliable?
The price and inventory of 74VHCT257ATTR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 74VHCT257ATTR is usually 5 days.
3.What payment methods are accepted for 74VHCT257ATTR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 74VHCT257ATTR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 74VHCT257ATTR?
74VHCT257ATTR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 74VHCT257ATTR 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 74VHCT257ATTR?
For technical support, including 74VHCT257ATTR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 74VHCT257ATTR requirements.
6.How does Aetrix verify that 74VHCT257ATTR is sourced from the original manufacturer or authorized distributors?
All 74VHCT257ATTR 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 74VHCT257ATTR meets industry standards.
7.What is the process for return or replacement of 74VHCT257ATTR?
All 74VHCT257ATTR units undergo pre-shipment inspection (PSI). If there is an issue with 74VHCT257ATTR, 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 74VHCT257ATTR part is unused and in its original packaging.
Return procedure for 74VHCT257ATTR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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