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Texas Instruments SN74CB3T3257PW
- Part No.:
- SN74CB3T3257PW
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
SN74CB3T3257PW.pdf
- Description:
- IC MUX/DEMUX 4 X 2:1 16TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,004
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Product details
Overview
SN74CB3T3257PW from Texas Instruments is a 4-bit 1-of-2 FET multiplexer/demultiplexer with bidirectional signal flow, 5Ω typical ON-state resistance, 5V-tolerant I/Os, and VCC-referenced voltage translation supporting 2.3V–3.6V operation. It enables level-shifting between 5V, 3.3V, and 2.5V logic domains in USB interfaces and memory interleaving systems.
For engineers reviewing the SN74CB3T3257PW datasheet, SN74CB3T3257PW pinout, SN74CB3T3257PW application, or SN74CB3T3257PW equivalent, key selection criteria include its 5V-tolerant I/Os during power-up/down, Ioff partial-power-down protection, near-zero propagation delay (≤0.25 ns), and TSSOP-16 package compatibility with high-density PCB layouts.
Technical Context
The SN74CB3T3257PW implements four independent FET-based analog switches controlled by a shared select (S) input and active-low output enable (OE). Each switch supports rail-to-rail signal transmission with voltage translation that tracks VCC, enabling mixed-mode operation across 0V–5V data I/Os while powered from 2.3V–3.6V.
Its architecture integrates undershoot clamp diodes on all I/Os and control inputs, supports ±128 mA per channel continuous current, and guarantees isolation during power-off via Ioff functionality-verified to limit backflow current to ±10 µA at 0V VCC and 0V–5.5V I/O voltage.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC range | 2.3 V to 3.6 V - defines minimum/maximum supply for guaranteed operation and voltage translation tracking |
| ON-state resistance (rON) | 5 Ω typ at 2.5 V VCC - ensures minimal insertion loss and signal integrity for high-speed digital buses |
| I/O voltage range | 0 V to 5.5 V - enables 5V-tolerant interfacing regardless of VCC state, including hot-plug and partial-power-down scenarios |
| Propagation delay (tpd) | 0.25 ns max at 3.3 V - delivers near-zero latency for bidirectional data paths in timing-critical applications |
| Supply current (ICC) | 20 µA max - supports ultra-low static power in battery-powered portable equipment |
| Off-state capacitance (Cio(OFF)) | 5 pF typ on B ports - minimizes capacitive loading and crosstalk when switches are disabled |
| ESD rating (HBM) | ±2000 V - meets Class II human-body model requirements for robust handling in manufacturing and field use |
Pinout & Package
TSSOP-16 (PW) package: 5.00 mm × 6.40 mm body, 0.65 mm lead pitch, surface-mount, RoHS-compliant with NiPdAu lead finish and MSL Level-1 rating.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1A, 2A, 3A, 4A | Common I/O port (multiplexer input/output) | Connects bidirectionally to selected B port; serves as shared data path for each 1-of-2 channel |
| 1B1–4B1 | Channel 1–4 input/output port 1 | First selectable path per channel; used for primary bus routing or default device interface |
| 1B2–4B2 | Channel 1–4 input/output port 2 | Second selectable path per channel; enables dynamic bus reconfiguration or dual-device arbitration |
| S | Select control input | Determines whether A port connects to B1 (S = L) or B2 (S = H); TTL/CMOS-compatible |
| OE | Active-low output enable | Disables all switches into high-impedance state when high; requires pullup to VCC for power-up safety |
| VCC | Positive supply | Power source for internal switch biasing and level translation reference; must be decoupled with 0.1 µF capacitor |
| GND | Ground reference | Return path for all I/O and supply currents; critical for noise immunity and ESD discharge path |
Key Features
| Feature | Design Value |
|---|---|
| 5V-tolerant I/Os with VCC off | Supports hot-swap and partial-power-down without damage; VI/O withstands −0.5 V to 7 V regardless of VCC state |
| Voltage translation tracking VCC | Output levels follow VCC (e.g., 5 V input → 3.3 V output with 3.3 V VCC), enabling seamless mixed-voltage system integration |
| Ioff partial-power-down protection | Limits backflow current to ±10 µA when VCC = 0 V, preventing unintended current paths in unpowered subsystems |
| Bidirectional low-latency switching | 0.25 ns max tpd at 3.3 V ensures deterministic timing for DDR, USB, and memory bus applications |
| Low input/output capacitance | 5 pF Cio(OFF) on B ports reduces loading and maintains signal rise/fall times up to 200 MHz |
Applications
| USB Interface Isolation | Memory Interleaving |
|---|---|
|
Use Scenario: Isolating USB 2.0 data lines between host controller and peripheral during enumeration or fault conditions. IC Role / Device Role / Timing Role: Bidirectional 1-of-2 switch enabling dynamic routing of D+ and D− signals between two USB devices sharing one controller port. Use Value: Eliminates need for external level shifters and enables 5V-tolerant signaling while operating from 3.3V supply, reducing BOM count and layout area. |
Use Scenario: Alternating access between two identical SRAM banks using a single address/data bus. IC Role / Device Role / Timing Role: 4-bit multiplexer synchronizing 4-bit address or data lanes under S and OE control to prevent bus contention. Use Value: Achieves 2× memory bandwidth expansion with zero added propagation delay, preserving timing margins in high-speed embedded systems. |
| Level Translation Bridge | Bus Isolation for Power Domains |
|
Use Scenario: Connecting a 5V microcontroller GPIO to a 2.5V sensor interface without external resistive dividers. IC Role / Device Role / Timing Role: Voltage-translating switch converting 5V logic inputs to 2.5V outputs while maintaining full rail-to-rail swing. Use Value: Delivers accurate logic thresholds across voltage domains with no static current draw, improving power efficiency over resistor-based solutions. |
Use Scenario: Isolating a 3.3V FPGA configuration bus from a 5V power management IC during FPGA power-up sequencing. IC Role / Device Role / Timing Role: High-impedance disconnect switch activated by OE to prevent backfeeding into unpowered FPGA I/O banks. Use Value: Enforces safe power sequencing by blocking leakage paths during partial-power-down, satisfying JESD78 latch-up immunity (>250 mA). |
Equivalent & Alternatives
The following parts are listed as comparable options for similar FET multiplexer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74CBTLV3257PW | Lower rON (3 Ω typ), 2.3V–3.6V VCC, same pinout but no 5V-tolerant I/Os - rated only to VCC + 0.3 V | Not suitable for 5V signal domains; requires strict voltage alignment between I/O and VCC | Choose when lowest possible insertion loss is required and all connected logic operates ≤3.6V |
| TS3A227EYZR | 3.3V-only VCC (1.65V–3.6V), 5V-tolerant I/Os, 0.7 Ω rON, but only 2-channel (4:1 mux), different pinout | Lacks 4-bit 1-of-2 architecture; requires PCB redesign and firmware adaptation for channel mapping | Consider only if higher channel density per package is needed and system can accommodate non-drop-in layout changes |
Compared with SN74CB3T3257PW, SN74CBTLV3257PW offers lower resistance but sacrifices 5V tolerance, while TS3A227EYZR provides superior rON and voltage flexibility but requires board-level redesign due to differing channel count and pin assignment.
Availability
SN74CB3T3257PW is available at Aetrix Electronics and suitable for USB interface isolation, memory interleaving, level translation bridges, and bus isolation requiring stable component supply across industrial, computing, and portable electronics programs.
Supply support for SN74CB3T3257PW 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 precision analog, power management, and logic devices.
The SN74CB3T3257PW belongs to TI's CB3T family of low-voltage bus switches, engineered specifically for high-speed, low-latency, mixed-voltage signal routing in portable, USB, and memory subsystem applications.
FAQ
What is the maximum data rate supported by the SN74CB3T3257PW?
The SN74CB3T3257PW has been tested up to 200 MHz in typical applications. Its 0.25 ns propagation delay and 5 pF off-state capacitance support clean signal edges at this frequency, provided PCB layout follows controlled-impedance practices and load capacitance remains ≤50 pF per channel.
Can the SN74CB3T3257PW operate with VCC disconnected while 5V signals are present on I/O pins?
Yes - the SN74CB3T3257PW is explicitly specified for 5V-tolerant operation with VCC powered up or powered down. Its I/Os withstand −0.5 V to 7 V regardless of VCC state, and Ioff limits backflow current to ±10 µA when VCC = 0 V, ensuring safe hot-swap capability.
How does the SN74CB3T3257PW handle voltage translation between 5V and 2.5V logic domains?
The SN74CB3T3257PW performs automatic voltage translation: with 2.5 V VCC, a 5V input on any B port produces a ~2.5V output on the A port, and vice versa. This tracking behavior is inherent to its FET gate drive architecture and requires no external components or configuration.
Is the SN74CB3T3257PW pin-compatible with other members of the SN74CB3T3257 family?
Yes - the SN74CB3T3257PW shares identical pinout and function mapping with SN74CB3T3257DGV and SN74CB3T3257DYY packages. All variants use the same 16-pin functional assignment (S, OE, 1A–4A, 1B1–4B2, VCC, GND), enabling direct substitution within footprint-constrained designs.
What decoupling capacitance is recommended for the SN74CB3T3257PW VCC pin?
A 0.1 µF ceramic capacitor placed as close as possible to the VCC pin is mandatory. TI specifies this value to suppress high-frequency supply noise and maintain stable switch biasing; larger bulk capacitance (e.g., 1 µF) may be added in parallel if system-level noise exceeds specification limits.
SN74CB3T3257PW Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74CB
- Package/Case:
- 16-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Tube
- 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:
- 2.3V ~ 3.6V
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-TSSOP
SN74CB3T3257PW FAQ
1.How can I place an order for SN74CB3T3257PW through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74CB3T3257PW 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 SN74CB3T3257PW reliable?
The price and inventory of SN74CB3T3257PW are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74CB3T3257PW is usually 5 days.
3.What payment methods are accepted for SN74CB3T3257PW?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74CB3T3257PW transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74CB3T3257PW?
SN74CB3T3257PW orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74CB3T3257PW 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 SN74CB3T3257PW?
For technical support, including SN74CB3T3257PW datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74CB3T3257PW requirements.
6.How does Aetrix verify that SN74CB3T3257PW is sourced from the original manufacturer or authorized distributors?
All SN74CB3T3257PW 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 SN74CB3T3257PW meets industry standards.
7.What is the process for return or replacement of SN74CB3T3257PW?
All SN74CB3T3257PW units undergo pre-shipment inspection (PSI). If there is an issue with SN74CB3T3257PW, 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 SN74CB3T3257PW part is unused and in its original packaging.
Return procedure for SN74CB3T3257PW:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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