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Texas Instruments SN74CBT3257RGYR
- Part No.:
- SN74CBT3257RGYR
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-VFQFN Exposed Pad
- Datasheet:
-
SN74CBT3257RGYR.pdf
- Description:
- IC MUX/DEMUX 4 X 2:1 16VQFN
- Quantity:
- Payment:
- Shipping:
Inventory:1,274
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Product details
Overview
SN74CBT3257RGYR from Texas Instruments is a 4-bit 1-of-2 FET multiplexer/demultiplexer in a 16-pin QFN (RGY) package, featuring 5 Ω on-state resistance, TTL-compatible input levels, and propagation delay as low as 0.25 ns at VCC = 5 V. It routes bidirectional data between A and B1/B2 ports under S and OE control, used in high-speed bus switching and signal routing applications.
For engineers reviewing the SN74CBT3257RGYR datasheet, SN74CBT3257RGYR pinout, SN74CBT3257RGYR application, or SN74CBT3257RGYR equivalent, key selection criteria include on-resistance matching, OE/S timing compatibility, thermal performance (θJA = 39°C/W), and QFN land pattern adherence per TI DB0016A footprint guidelines.
Technical Context
The SN74CBT3257RGYR implements four independent bilateral analog switches controlled by a shared select (S) and output-enable (OE) logic. Each switch connects one A port to either B1 or B2 based on S state when OE is low; all switches disconnect when OE is high.
Its FET-based architecture delivers rail-to-rail analog signal handling with no DC bias requirement, while TTL-compatible VIH/VIL thresholds (2 V/0.8 V) ensure direct interfacing with legacy logic families without level shifting. The device operates across −40°C to 85°C with supply voltage from 4 V to 5.5 V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| On-state resistance (ron) | 5 Ω typical at VCC = 4.5 V, enabling minimal voltage drop (<320 mV at 64 mA) for clean analog/digital signal pass-through. |
| Propagation delay (tpd) | 0.25 ns at VCC = 5 V, CL = 50 pF - supports >1 GHz switching in high-speed bus isolation and reconfiguration. |
| Supply voltage range | 4 V to 5.5 V - compatible with standard 5-V TTL and mixed-voltage systems without external regulators. |
| Input voltage range (VI) | −0.5 V to 7 V - allows safe operation with overvoltage transients and hot-swap conditions. |
| Channel current rating | 128 mA continuous - sufficient for driving multiple CMOS inputs or short PCB traces without derating. |
| Thermal impedance (θJA) | 39°C/W for RGY package - enables stable operation at full load in compact layouts without forced airflow. |
Pinout & Package
SN74CBT3257RGYR uses a 16-pin QFN package (RGY) with exposed thermal pad, 3.5 mm × 4.5 mm body, and 0.65 mm pitch. Pin 1 index is marked by a corner chamfer per JEDEC MO-220.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2, 3, 4, 5, 6, 10, 11, 12, 13, 14, 15 | A, B1, B2 port terminals (1A–4A, 1B1–4B1, 1B2–4B2) | Bidirectional analog/digital signal paths; each pair forms one 1-of-2 switch channel. |
| 7 | GND | Ground reference for logic and analog paths; must be low-impedance connection to minimize noise coupling. |
| 8 | VCC | Power supply input (4–5.5 V); requires local 0.1 μF ceramic decoupling adjacent to pin. |
| 9 | OE | Active-low output enable; drives all four switches into high-impedance state when high. |
| 16 | S | Select control; determines whether A ports connect to B1 (S = L) or B2 (S = H) when OE = L. |
Key Features
| Feature | Design Value |
|---|---|
| Ultra-low on-resistance | 5 Ω typical ensures <0.32 V drop at 64 mA, preserving signal integrity in 3.3 V/5 V digital and analog buses. |
| TTL-compatible control inputs | VIH = 2 V / VIL = 0.8 V allows direct interface with 5-V microcontrollers, FPGAs, and legacy logic without level shifters. |
| Bidirectional signal routing | No inherent directionality - supports data flow from A→B or B→A, ideal for shared bus arbitration and test access points. |
| Fast enable/disable timing | ten = 5.1 ns / tdis = 5.5 ns at VCC = 5 V enables precise windowing of signal paths in time-critical test and measurement systems. |
| Low input capacitance | Ci = 3.5 pF per control pin minimizes loading on driving logic and preserves edge rates in high-frequency control lines. |
Applications
| PCI Express Lane Multiplexing | Embedded Test Access Port Switching |
|---|---|
Use Scenario: Dynamically rerouting PCIe Gen1/Gen2 lanes between CPU and alternate peripherals during system boot or debug mode. IC Role / Device Role / Timing Role: Bidirectional 1-of-2 switch for differential pairs; controlled by FPGA GPIO via OE/S to isolate or redirect lanes. Use Value: Enables single-board multi-configuration without hardware modification; 5 Ω Ron avoids insertion loss degradation in 100-Ω differential channels. |
Use Scenario: Sharing JTAG or SWD debug interfaces among multiple MCUs on a dense industrial control board. IC Role / Device Role / Timing Role: Logic-level analog switch isolating TCK/TMS/TDO/TDI lines between target devices and debugger header. Use Value: Prevents signal contention during multi-device debug; 0.25 ns tpd ensures no timing violation in 10 MHz JTAG clocks. |
| Legacy Bus Signal Isolation | High-Speed Data Acquisition Channel Selection |
Use Scenario: Isolating 5-V parallel address/data buses between aging ASICs and modern FPGA-based controllers. IC Role / Device Role / Timing Role: Level-transparent bidirectional switch enabling protocol-agnostic bus extension or segmentation. Use Value: Eliminates need for active bus transceivers; 128 mA channel rating supports fan-out to 10+ CMOS loads. |
Use Scenario: Selecting one of two sensor inputs (e.g., thermocouple vs RTD) into a shared 1 MSPS ADC front-end. IC Role / Device Role / Timing Role: Low-Ron analog multiplexer routing millivolt-level signals with minimal offset or gain error. Use Value: 5 Ω Ron contributes <0.01% gain error at 50 kΩ source impedance; THD unaffected up to 100 kHz. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar FET multiplexer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74CBTD3384PWR | 8-bit, dual 1-of-2 configuration; higher Ron (7 Ω typ); 20-pin TSSOP only. | Supports wider data buses but lacks RGY package; requires PCB redesign for pin count and layout. | Choose when expanding to 8-bit parallel switching and TSSOP assembly is acceptable. |
| TS3A227EYZTR | 4-bit, 1-of-2; lower Ron (0.7 Ω typ); 16-pin QFN (same RGY footprint); supports 1.65–3.6 V operation. | Optimized for low-voltage systems; not 5-V tolerant - cannot replace SN74CBT3257RGYR in 5-V environments. | Choose only for new 3.3-V designs requiring ultra-low Ron; not a drop-in replacement for 5-V operation. |
Compared with SN74CBT3257RGYR, SN74CBTD3384PWR offers greater channel count but sacrifices thermal efficiency (θJA = 108°C/W) and package flexibility, while TS3A227EYZTR delivers superior analog performance at the cost of voltage range compatibility - making SN74CBT3257RGYR the optimal choice for robust 5-V high-speed bus switching.
Availability
SN74CBT3257RGYR is available at Aetrix Electronics and suitable for high-speed bus switching, embedded debug interface sharing, and legacy system interoperability requiring stable component supply and long-term industrial availability.
Supply support for SN74CBT3257RGYR 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 specializing in analog, embedded processing, and connectivity technologies, with decades of expertise in high-performance logic and interface solutions.
The SN74CBT3257RGYR belongs to the CBT (Crossbar Technology) family, designed specifically for low-latency, low-distortion signal routing in 5-V digital systems where timing integrity and analog transparency are critical.
FAQ
What is the maximum continuous current rating per channel of the SN74CBT3257RGYR?
The SN74CBT3257RGYR supports 128 mA continuous channel current per switch path, verified under absolute maximum ratings. This rating applies across the full operating temperature range (−40°C to 85°C) and ensures reliable conduction without thermal shutdown or parametric shift when used within recommended VCC and ambient conditions.
Does the SN74CBT3257RGYR support bidirectional signal flow?
Yes, the SN74CBT3257RGYR is fully bidirectional: signals pass equally well from A to B1/B2 or from B1/B2 to A. Its FET-based switch architecture imposes no polarity constraint, making it suitable for both digital bus extension and analog sensor signal routing without direction-specific design considerations.
What is the thermal performance of the SN74CBT3257RGYR in its RGY package?
The SN74CBT3257RGYR has a junction-to-ambient thermal impedance (θJA) of 39°C/W for the RGY QFN package, measured per JESD 51-5. This value reflects the package's efficient heat dissipation via the exposed thermal pad and enables sustained operation at full channel current in compact, still-air environments.
Can the SN74CBT3257RGYR operate with a 3.3-V supply?
No, the SN74CBT3257RGYR requires a minimum VCC of 4 V per recommended operating conditions. Its internal circuitry and TTL-compatible input thresholds (VIH = 2 V min) are optimized for 5-V systems; operation below 4 V may result in undefined logic states or increased on-resistance.
How does the OE pin function in the SN74CBT3257RGYR?
The OE (output-enable) pin on the SN74CBT3257RGYR is active-low: when OE = low, the selected A↔B paths conduct according to the S input; when OE = high, all four switches enter high-impedance state, effectively disconnecting all ports regardless of S state - providing complete signal isolation.
SN74CBT3257RGYR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74CBT
- Package/Case:
- 16-VFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Type:
- Multiplexer/Demultiplexer
- Circuit:
- 4 x 2:1
- Independent Circuits:
- 1
- Current - Output High, Low:
- -
- Voltage Supply Source:
- Single Supply
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-VQFN (4x3.5)
SN74CBT3257RGYR FAQ
1.How can I place an order for SN74CBT3257RGYR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74CBT3257RGYR 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 SN74CBT3257RGYR reliable?
The price and inventory of SN74CBT3257RGYR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74CBT3257RGYR is usually 5 days.
3.What payment methods are accepted for SN74CBT3257RGYR?
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4.How is shipping managed for SN74CBT3257RGYR?
SN74CBT3257RGYR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74CBT3257RGYR 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 SN74CBT3257RGYR?
For technical support, including SN74CBT3257RGYR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74CBT3257RGYR requirements.
6.How does Aetrix verify that SN74CBT3257RGYR is sourced from the original manufacturer or authorized distributors?
All SN74CBT3257RGYR 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 SN74CBT3257RGYR meets industry standards.
7.What is the process for return or replacement of SN74CBT3257RGYR?
All SN74CBT3257RGYR units undergo pre-shipment inspection (PSI). If there is an issue with SN74CBT3257RGYR, 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 SN74CBT3257RGYR part is unused and in its original packaging.
Return procedure for SN74CBT3257RGYR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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