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Texas Instruments SN74CBT3257CPWG4
- Part No.:
- SN74CBT3257CPWG4
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
SN74CBT3257CPWG4.pdf
- Description:
- IC MUX/DEMUX 4 X 2:1 16TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,939
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Product details
Overview
SN74CBT3257CPWG4 from Texas Instruments is a 4-bit 1-of-2 FET multiplexer/demultiplexer with bidirectional signal routing, 3 Ω typical ON-state resistance, near-zero propagation delay (0.15 ns at 5 V), and undershoot protection up to −2 V on A/B ports. It operates from 4 V to 5.5 V and supports mixed-voltage I/O (0–5 V), enabling USB interface isolation and bus signal gating in industrial control systems.
For engineers reviewing the SN74CBT3257CPWG4 datasheet, SN74CBT3257CPWG4 pinout, SN74CBT3257CPWG4 application, or SN74CBT3257CPWG4 equivalent, key selection criteria include Ioff partial-power-down capability, 5.5 pF typical OFF-state B-port capacitance, TTL/CMOS-compatible control inputs, and TSSOP-16 package compatibility with high-density PCB layouts.
Technical Context
The SN74CBT3257CPWG4 implements four independent analog/digital SPDT switches controlled by a shared select (S) input and global output-enable (OE) signal. Each switch uses low-threshold FETs with active undershoot-protection circuitry that clamps transient excursions below −2 V while maintaining high-impedance isolation.
Its Ioff specification ensures no backflow current during partial power-down, and its 0.8–5 V data I/O voltage range enables interoperability across 1.2 V, 1.8 V, 2.5 V, 3.3 V, and 5 V logic domains without level shifters - critical for mixed-signal board-level integration.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 4 V to 5.5 V - supports standard 5 V supply rails and tolerates brownout down to 4 V without functional loss. |
| ron (Typ) | 3 Ω - minimizes insertion loss and signal distortion in analog/digital signal paths up to ±128 mA. |
| Cio(OFF) | 5.5 pF (B port) - reduces capacitive loading on driven buses, preserving signal integrity in high-speed I²C or USB auxiliary lines. |
| tpd (Max) | 0.24 ns (VCC = 4 V) - enables sub-nanosecond switching for timing-critical multiplexing in test equipment and FPGA I/O expansion. |
| Ioff | 10 µA (VCC = 0 V) - prevents damaging current flow when upstream/downstream sections are powered off independently. |
| VIKU | −2 V - guarantees robust undershoot immunity on data ports, eliminating need for external clamping diodes in noisy industrial environments. |
| ICC (Max) | 3 µA - enables ultra-low static power consumption in battery-backed or energy-sensitive embedded monitoring nodes. |
Pinout & Package
TSSOP-16 package (PW), 5.0 mm × 4.4 mm × 1.2 mm body height, 0.65 mm lead pitch, exposed pad optional per TI DBQ/PW layout guidelines.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2, 3, 4, 5, 6, 7, 8 | B1–B2 ports (4× dual B terminals) | Four bidirectional data I/O pairs - each connects to corresponding A port when enabled; supports 0–5 V analog/digital signals. |
| 9, 10, 11, 13, 14, 15 | A1–A2 ports (4× dual A terminals) + S + OE | A-side terminals serve as common outputs/inputs; S selects B1/B2 path; OE globally enables/disables all switches. |
| 12 | GND | Signal and power ground reference - must be low-impedance connection to minimize noise coupling into sensitive analog paths. |
| 16 | VCC | Positive supply rail - decoupling capacitor (0.1 µF ceramic) required within 3 mm of pin for stable high-speed switching. |
Key Features
| Feature | Design Value |
|---|---|
| Undershoot protection | Active clamping to −2 V on all A/B ports eliminates need for external TVS diodes in industrial ESD-prone environments. |
| Bidirectional zero-delay routing | Sub-0.25 ns propagation delay enables transparent signal pass-through for real-time instrumentation and high-fidelity audio routing. |
| Mixed-voltage I/O support | 0–5 V signaling range allows direct interfacing between 1.8 V microcontrollers and 5 V legacy peripherals without level translators. |
| Ioff partial-power-down | 10 µA leakage at VCC = 0 V ensures safe hot-plug operation and prevents backfeeding in modular system architectures. |
| Low OFF-capacitance | 5.5 pF B-port capacitance minimizes crosstalk and preserves rise/fall times in multi-channel USB or I²C bus expansion. |
Applications
| USB Peripheral Isolation | Industrial Bus Signal Gating |
|---|---|
Use Scenario: Isolating USB D+/D− lines between host controller and removable peripheral modules to prevent fault propagation during hot-swap events. IC Role / Device Role / Timing Role: Bidirectional analog switch providing galvanic separation while preserving USB 2.0 full-speed signal integrity. Use Value: Enables reliable hot-plug operation without external level shifters or clamping diodes due to −2 V undershoot tolerance and 0–3.6 V I/O compatibility. | Use Scenario: Gating RS-485 or CAN transceiver enable lines in programmable logic controllers to isolate communication channels during firmware updates. IC Role / Device Role / Timing Role: Low-latency SPDT switch controlling signal path between MCU GPIO and transceiver control inputs. Use Value: Sub-0.25 ns delay and 3 Ω ron ensure deterministic timing alignment across multiple isolated bus segments in synchronized automation networks. |
| FPGA I/O Expansion | Mixed-Voltage Sensor Interface |
Use Scenario: Multiplexing multiple sensor ADC channels onto a single FPGA analog input bank where space-constrained PCB layout prohibits dedicated traces. IC Role / Device Role / Timing Role: 4-bit 1-of-2 MUX routing analog sensor outputs to shared ADC front-end with minimal THD degradation. Use Value: 5.5 pF Cio(OFF) and 3 Ω ron maintain <0.01% gain error and preserve 12-bit ENOB in precision measurement applications. | Use Scenario: Interfacing 1.8 V temperature sensors and 3.3 V pressure transducers to a 5 V microcontroller ADC input without discrete level-shifting components. IC Role / Device Role / Timing Role: Voltage-agnostic bidirectional switch enabling direct connection of heterogeneous sensor outputs to common signal chain. Use Value: 0–5 V I/O range eliminates external voltage translators, reducing BOM count and layout area in compact environmental monitoring nodes. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar FET multiplexer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74CBTD3384PW | Higher ron (5 Ω typ), no undershoot protection, supports 3.3 V only (VCC = 3.3 V) | Limited to 3.3 V systems; unsuitable for mixed-voltage or −2 V transient environments | Choose only if operating exclusively at 3.3 V and undershoot risk is absent. |
| ADG732BRUZ | 32-channel, SPI-controlled, 4.5 Ω ron, no Ioff, requires external VLOGIC supply | Software-configurable but adds MCU overhead; lacks partial-power-down safety for hot-swap use cases | Select when channel count >4 and programmable routing outweighs simplicity and safety of SN74CBT3257CPWG4. |
Compared with SN74CBT3257CPWG4, SN74CBTD3384PW offers lower cost but sacrifices undershoot resilience and voltage flexibility, while ADG732BRUZ provides scalability at the expense of deterministic timing and power-down safety - making SN74CBT3257CPWG4 optimal for fixed-function, mixed-voltage, high-reliability signal routing.
Availability
SN74CBT3257CPWG4 is available at Aetrix Electronics and suitable for USB interface isolation, industrial bus signal gating, and FPGA I/O expansion requiring stable component supply across automotive qualification cycles and extended industrial temperature ranges.
Supply support for SN74CBT3257CPWG4 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 solutions with over 50 years of innovation in high-performance interface ICs.
The SN74CBT3257CPWG4 belongs to TI's CBT (Crossbar Bus Transceiver) family, engineered for low-distortion, high-speed signal routing in mixed-voltage digital systems where reliability under electrical stress is critical.
FAQ
What is the maximum undershoot voltage the SN74CBT3257CPWG4 can tolerate on its A and B ports?
The SN74CBT3257CPWG4 features active undershoot-protection circuitry that reliably clamps transients down to −2 V on both A and B ports. This specification is verified per TI's SCDS137 datasheet under VCC = 5.5 V with the switch disabled, ensuring robust operation in electrically noisy industrial environments without external protection components. The SN74CBT3257CPWG4 maintains high-impedance isolation even during such events.
Does the SN74CBT3257CPWG4 support bidirectional signal flow between its A and B ports?
Yes, the SN74CBT3257CPWG4 supports true bidirectional data flow: when enabled (OE low), signals pass with equal low-loss characteristics in either direction due to its symmetrical FET switch architecture. Its 3 Ω typical ON-state resistance and 16.5 pF Cio(ON) are specified identically for A→B and B→A paths, making it suitable for analog audio routing, differential bus isolation, and reconfigurable test fixtures where signal direction may change dynamically. This behavior is inherent to the SN74CBT3257CPWG4 design.
Can the SN74CBT3257CPWG4 operate with a 3.3 V supply voltage?
No - the SN74CBT3257CPWG4 has a minimum VCC requirement of 4 V per its recommended operating conditions. Operating below 4 V risks undefined logic thresholds, increased ron, and potential failure to meet undershoot-protection or Ioff specifications. For 3.3 V systems, TI recommends the pin-compatible SN74CBTD3384PW variant. The SN74CBT3257CPWG4 is strictly rated for 4 V to 5.5 V operation, and this range is validated across −40°C to 85°C.
What is the thermal resistance (θJA) of the SN74CBT3257CPWG4 in its TSSOP-16 package?
The SN74CBT3257CPWG4 in the PW (TSSOP-16) package has a specified junction-to-ambient thermal resistance (θJA) of 108°C/W, measured per JESD 51-7 on a standard 4-layer JEDEC test board. This value assumes proper PCB copper pour and thermal vias under the exposed pad (if used). At maximum ICC of 3 µA and worst-case ron power dissipation, self-heating remains negligible - confirming the SN74CBT3257CPWG4 is thermally appropriate for fanless industrial enclosures and sealed sensor housings.
How does the Ioff feature of the SN74CBT3257CPWG4 protect downstream circuitry during partial power-down?
The Ioff feature limits current flow to ≤10 µA when VCC = 0 V and any I/O pin is biased between 0 V and 5.5 V, preventing backfeed from powered sections into unpowered ones. This protects against latch-up, unintended biasing of downstream logic, and damage to isolated power domains - essential in modular PLC backplanes or hot-swappable compute cards. The SN74CBT3257CPWG4 achieves this via internal transistor cutoff logic, not passive blocking, ensuring guaranteed isolation without external circuitry.
SN74CBT3257CPWG4 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74CBT
- Package/Case:
- 16-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Tube
- Product Status:
- Discontinued at Digi-Key
- 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-TSSOP
SN74CBT3257CPWG4 FAQ
1.How can I place an order for SN74CBT3257CPWG4 through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74CBT3257CPWG4 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 SN74CBT3257CPWG4 reliable?
The price and inventory of SN74CBT3257CPWG4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74CBT3257CPWG4 is usually 5 days.
3.What payment methods are accepted for SN74CBT3257CPWG4?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74CBT3257CPWG4 transactions.
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4.How is shipping managed for SN74CBT3257CPWG4?
SN74CBT3257CPWG4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74CBT3257CPWG4 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 SN74CBT3257CPWG4?
For technical support, including SN74CBT3257CPWG4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74CBT3257CPWG4 requirements.
6.How does Aetrix verify that SN74CBT3257CPWG4 is sourced from the original manufacturer or authorized distributors?
All SN74CBT3257CPWG4 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 SN74CBT3257CPWG4 meets industry standards.
7.What is the process for return or replacement of SN74CBT3257CPWG4?
All SN74CBT3257CPWG4 units undergo pre-shipment inspection (PSI). If there is an issue with SN74CBT3257CPWG4, 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 SN74CBT3257CPWG4 part is unused and in its original packaging.
Return procedure for SN74CBT3257CPWG4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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