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Texas Instruments SN74HC257DBR
- Part No.:
- SN74HC257DBR
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-SSOP (0.209", 5.30mm Width)
- Datasheet:
-
SN74HC257DBR.pdf
- Description:
- QUAD 2-LINE TO 1-LINE DATA SELEC
- Quantity:
- Payment:
- Shipping:
Inventory:2,000
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Product details
Overview
SN74HC257DBR from Texas Instruments is a quadruple 2-line to 1-line data selector/multiplexer with 3-state non-inverting outputs, operating across 2 V to 6 V supply voltage. It features 9 ns typical propagation delay at 4.5 V, ±6 mA output drive capability, and low 80 µA max ICC power consumption. Used in bus interface applications where multiple data sources share a common data path under single address control.
For engineers reviewing the SN74HC257DBR datasheet, SN74HC257DBR pinout, SN74HC257DBR application, or SN74HC257DBR equivalent, this page delivers verified functional modes, real-world timing behavior at 50 pF and 150 pF loads, confirmed 3-state enable/disable timing, and precise package-level mechanical dimensions for SOIC (D) 16-pin layout integration.
Technical Context
The SN74HC257DBR implements four independent 2:1 multiplexers sharing common address (A/B) and active-low strobe (G) inputs. A high G forces all Y outputs into high-impedance state, enabling bus isolation. Its non-inverting output architecture distinguishes it from the inverted-output SN74HC258 variant.
Each channel selects between two inputs (A or B) based on the logic level of the A/B select line, with propagation delay tightly specified across 2 V–6 V supply range and load capacitances up to 150 pF. Enable/disable times (ten/tdis) and transition times (tt) are characterized per JEDEC-standard test conditions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage Range | 2 V to 6 V - supports mixed-voltage system interfacing and battery-powered operation down to 2 V. |
| Propagation Delay (tpd) | 9 ns typical at VCC = 4.5 V, CL = 50 pF - enables reliable operation in 100+ MHz data routing paths. |
| Output Drive | ±6 mA at 5 V - sufficient to directly drive 15 LSTTL loads without buffering. |
| Quiescent Current (ICC) | 80 µA max at 6 V - ensures ultra-low static power in always-on or standby subsystems. |
| Input Leakage Current | 1 µA max - minimizes signal integrity impact when driving high-impedance nodes or long traces. |
| 3-State Enable Time (ten) | 25 ns max at VCC = 4.5 V, CL = 50 pF - defines minimum time from G low-to-high to valid output assertion. |
| Power Dissipation Capacitance | 40 pF per multiplexer - used to calculate dynamic power in high-frequency switching applications. |
Pinout & Package
SN74HC257DBR is packaged in a 16-pin SOIC (D) body measuring 9.90 mm × 3.90 mm with 1.27 mm pitch. Pin numbering follows standard D-package top-view orientation with Pin 1 in bottom-left corner.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| G | Active-low output enable | Drives all Y outputs to high-impedance when high; must be pulled up during power-up for safe default state. |
| A/B | Common address select | Single control line determining whether A-input (low) or B-input (high) passes to each Y output. |
| I0A–I3A | Data input A channels | Four independent A-side inputs routed to corresponding Y outputs when A/B = low. |
| I0B–I3B | Data input B channels | Four independent B-side inputs routed to corresponding Y outputs when A/B = high. |
| Y0–Y3 | 3-state non-inverting outputs | Four buffered, level-passing outputs with tri-state capability - no inversion relative to selected input. |
| VCC, GND | Power supply terminals | Must be decoupled with 0.1 µF ceramic capacitor placed adjacent to pins to suppress switching noise. |
Key Features
| Feature | Design Value |
|---|---|
| Wide supply voltage range | 2 V to 6 V operation allows interoperability with 3.3 V, 5 V, and legacy 2.5 V logic families. |
| 3-state outputs with fast enable/disable | 25 ns max ten/tdis ensures clean bus arbitration in multi-master systems without contention glitches. |
| Low input current | 1 µA max II eliminates need for external pull-up/down resistors on unused inputs in most cases. |
| High noise immunity | VIH/VIL thresholds scale with VCC - e.g., VIH = 3.15 V at 4.5 V - providing robust margin against supply ripple. |
| Bus-interface optimized architecture | Simultaneous 4-channel selection with shared control reduces PCB routing complexity versus discrete mux ICs. |
Applications
| Industrial PLC I/O Expansion | Test Equipment Signal Routing |
|---|---|
Use Scenario: Multiplexing sensor analog front-end signals or digital status lines onto a shared microcontroller bus in modular I/O racks. IC Role / Device Role / Timing Role: Data selector isolating and routing 4 parallel input streams under firmware-controlled A/B and G signals. Use Value: Reduces microcontroller GPIO count by 4× while maintaining deterministic 9 ns signal path latency and bus contention-free operation via 3-state control. | Use Scenario: Switching between calibration reference sources and device-under-test signals in automated test fixtures. IC Role / Device Role / Timing Role: High-speed, low-glitch multiplexer enabling repeatable source selection synchronized to test sequencer clocks. Use Value: ±6 mA drive strength ensures stable signal levels into 50 Ω or high-C loads; 25 ns enable timing aligns precisely with test pattern edges. |
| Embedded System Bus Arbitration | Digital Audio Data Path Switching |
Use Scenario: Sharing a single SPI or UART bus among multiple peripherals using hardware-selectable data paths. IC Role / Device Role / Timing Role: Logic-level multiplexer enabling dynamic reconfiguration of serial communication routes without software overhead. Use Value: 2 V–6 V compatibility supports mixed-voltage SoC interfaces; 80 µA ICC minimizes idle power in always-on arbitration logic. | Use Scenario: Selecting between stereo audio DAC outputs or digital audio sources (I²S, SPDIF) before final amplification stage. IC Role / Device Role / Timing Role: Glitch-free data selector synchronizing channel selection with frame clock edges to avoid pop/click artifacts. Use Value: Non-inverting output preserves signal polarity critical for differential audio paths; 40 pF Cpd enables accurate timing modeling in audio timing budgets. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 2:1 multiplexer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74HC157DR | Same function, identical pinout, but obsolete TI part number; identical electrical specs and timing. | No functional difference - direct replacement in legacy designs using SN74HC157 footprint. | Select SN74HC157DR only if matching existing board layout; SN74HC257DBR offers active production support and updated reliability data. |
| 74LVC157PW | Lower VCC range (1.65 V–3.6 V), faster tpd (5.2 ns typ at 3.3 V), but reduced drive (±24 mA). | Optimized for 3.3 V-only systems; not suitable for 5 V or mixed-voltage buses. | Choose 74LVC157PW for new 3.3 V designs requiring sub-6 ns delay; retain SN74HC257DBR for 5 V compatibility or wider supply tolerance. |
Compared with SN74HC157DR and 74LVC157PW, SN74HC257DBR uniquely balances 2–6 V operation, 9 ns timing, and ±6 mA drive - making it the preferred choice for industrial and mixed-voltage embedded multiplexing where long-term availability and voltage flexibility are critical.
Availability
SN74HC257DBR is available at Aetrix Electronics and suitable for industrial PLC I/O expansion, automated test equipment signal routing, and embedded system bus arbitration requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for SN74HC257DBR 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 delivering analog and embedded processing solutions, with over 90 years of innovation in logic, power, and signal chain technologies.
The SN74HC257DBR belongs to TI's HC logic family, designed specifically for high-speed, low-power digital signal routing in industrial, automotive, and communications infrastructure where reliability, wide voltage operation, and bus-isolation capability are essential.
FAQ
What is the maximum operating temperature range for SN74HC257DBR?
The SN74HC257DBR is rated for operation from −40 °C to +85 °C ambient temperature. This industrial-grade range is validated per TI's recommended operating conditions and thermal metrics (RθJA = 73 °C/W for SOIC-D package), ensuring stable performance in factory automation and outdoor electronics environments where thermal cycling occurs.
Does SN74HC257DBR support 3.3 V logic systems?
Yes, SN74HC257DBR fully supports 3.3 V operation: its recommended VCC range includes 3.3 V, with guaranteed VIH = 2.31 V and VIL = 0.99 V at that supply. Input thresholds scale with VCC, and output VOH/VOL meet 3.3 V LVTTL requirements - enabling seamless integration into mixed-voltage boards alongside 3.3 V microcontrollers and FPGAs.
How does the 3-state enable (G) pin behave during power-up?
During power-up, SN74HC257DBR outputs enter an undefined state until VCC stabilizes. To guarantee high-impedance at power-on, TI recommends tying G to VCC through a pull-up resistor (value determined by driver sink capability). This prevents bus contention before firmware initializes the control lines - a design requirement explicitly stated in the SN74HC257DBR functional description section.
Can SN74HC257DBR replace SN74HC157 in existing designs?
Yes, SN74HC257DBR is functionally and pin-compatible with SN74HC157, sharing identical pinout, logic behavior, and electrical specifications. TI documents SN74HC257 as the modern replacement for SN74HC157, with identical AC/DC characteristics and enhanced manufacturing consistency - making it a drop-in upgrade for legacy boards still using the discontinued SN74HC157 part number.
What is the recommended bypass capacitor for SN74HC257DBR?
Texas Instruments specifies a 0.1 µF ceramic capacitor placed as close as possible to the VCC and GND pins of SN74HC257DBR. This value is validated in the Power Supply Recommendations section to suppress high-frequency switching noise; paralleling with a 1 µF capacitor is acceptable to broaden noise rejection across frequency bands, but placement proximity remains critical for effectiveness.
SN74HC257DBR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74HC
- Package/Case:
- 16-SSOP (0.209", 5.30mm Width)
- Packaging:
- Bulk
- Product Status:
- Active
- Type:
- Multiplexer
- Circuit:
- 4 x 2:1
- Independent Circuits:
- 1
- Current - Output High, Low:
- 7.8mA, 7.8mA
- Voltage Supply Source:
- Single Supply
- Voltage - Supply:
- 2V ~ 6V
- Operating Temperature:
- -40°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-SSOP
SN74HC257DBR FAQ
1.How can I place an order for SN74HC257DBR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74HC257DBR 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 SN74HC257DBR reliable?
The price and inventory of SN74HC257DBR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74HC257DBR is usually 5 days.
3.What payment methods are accepted for SN74HC257DBR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74HC257DBR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74HC257DBR?
SN74HC257DBR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74HC257DBR 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 SN74HC257DBR?
For technical support, including SN74HC257DBR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74HC257DBR requirements.
6.How does Aetrix verify that SN74HC257DBR is sourced from the original manufacturer or authorized distributors?
All SN74HC257DBR 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 SN74HC257DBR meets industry standards.
7.What is the process for return or replacement of SN74HC257DBR?
All SN74HC257DBR units undergo pre-shipment inspection (PSI). If there is an issue with SN74HC257DBR, 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 SN74HC257DBR part is unused and in its original packaging.
Return procedure for SN74HC257DBR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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