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Texas Instruments SN74CBT3257PW
- Part No.:
- SN74CBT3257PW
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
SN74CBT3257PW.pdf
- Description:
- IC MUX/DEMUX 4 X 2:1 16TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,728
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Product details
Overview
SN74CBT3257PW from Texas Instruments is a 4-bit 1-of-2 FET multiplexer/demultiplexer in TSSOP-16 package, featuring 5 Ω typical on-state resistance, TTL-compatible control inputs (VIH = 2 V, VIL = 0.8 V), and propagation delay as low as 0.25 ns at VCC = 5 V. It enables bidirectional signal routing in high-speed digital interconnects such as bus isolation and data path switching.
For engineers reviewing the SN74CBT3257PW datasheet, SN74CBT3257PW pinout, SN74CBT3257PW application, or SN74CBT3257PW equivalent, key selection criteria include on-resistance matching across channels, OE/S-controlled channel selection timing, thermal performance (θJA = 108°C/W), and compatibility with 4–5.5 V supply rails in space-constrained PCB layouts.
Technical Context
The SN74CBT3257PW implements four independent bilateral analog switches controlled by a shared select (S) and output-enable (OE) logic interface. Each switch connects one A-terminal to either B1 or B2 based on S state when OE is low; all outputs disconnect when OE is high.
Its FET-based architecture delivers rail-to-rail analog signal handling, minimal charge injection (<0.5 pC), and low off-capacitance (4 pF), enabling clean switching of digital signals up to 100 MHz without distortion or timing skew between channels.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| On-state resistance (ron) | 5–7 Ω typical - ensures minimal voltage drop and signal attenuation for 64 mA channel current. |
| Propagation delay (tpd) | 0.25 ns at VCC = 5 V - supports sub-nanosecond timing integrity in high-speed bus applications. |
| Supply voltage range | 4 V to 5.5 V - compatible with standard 5 V TTL and mixed-voltage 4.5 V systems. |
| Input voltage thresholds | VIH = 2 V, VIL = 0.8 V - guarantees reliable logic-level recognition from legacy TTL drivers. |
| Off-state capacitance (Cio) | 4 pF - limits crosstalk and maintains signal integrity during channel disable. |
| Operating temperature | −40°C to +85°C - suitable for industrial-grade embedded control and communications equipment. |
| Package | TSSOP-16 (PW) - 5.0 × 4.4 mm footprint with 0.65 mm pitch, optimized for automated assembly and thermal dissipation. |
Pinout & Package
TSSOP-16 (PW) package: 5.0 mm × 4.4 mm body, 1.2 mm max height, 0.65 mm lead pitch, gull-wing leads, moisture sensitivity level (MSL) not specified in datasheet but consistent with JEDEC MO-153.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2, 3, 4, 5, 6, 11, 12, 13, 14, 15 | Data I/O terminals (1A–4A, 1B1–4B2) | Bidirectional analog/digital signal paths; each A port connects to corresponding B1/B2 under S/OE control. |
| 7 | GND | Power ground reference for internal FET bias and noise immunity. |
| 8 | VCC | Positive supply input (4–5.5 V); powers internal level shifters and switch FETs. |
| 9 | OE | Active-low output enable; high state disables all switches, isolating A and B ports. |
| 10 | S | Select control; determines whether A connects to B1 (S = L) or B2 (S = H) when OE = L. |
Key Features
| Feature | Design Value |
|---|---|
| Bidirectional signal routing | Enables reuse of same device for mux or demux roles without signal direction constraints. |
| 5 Ω low on-resistance | Reduces insertion loss and maintains signal amplitude integrity for 3.3 V/5 V logic levels. |
| TTL-compatible control inputs | Eliminates need for level-shifting circuitry when interfacing with legacy microcontrollers or FPGAs. |
| 0.25 ns propagation delay | Preserves timing margins in high-frequency data buses (e.g., address/data multiplexing). |
| 4 pF off-capacitance | Minimizes capacitive loading and crosstalk between adjacent channels in dense PCB layouts. |
Applications
| Bus Isolation | Signal Multiplexing |
|---|---|
|
Use Scenario: Isolating two microcontroller buses during firmware update to prevent contention. IC Role / Device Role / Timing Role: Bidirectional analog switch enabling/disabling data path between master and slave peripherals. Use Value: Prevents bus lock-up with <0.25 ns delay and <5 Ω resistance, ensuring glitch-free handover. |
Use Scenario: Routing one ADC output to multiple processing units in test instrumentation. IC Role / Device Role / Timing Role: 1-of-2 demultiplexer selecting destination for time-critical analog sample data. Use Value: Maintains signal fidelity with 4 pF off-capacitance and rail-to-rail swing support. |
| Logic-Level Translation | Hot-Swap Signal Switching |
|
Use Scenario: Interfacing 3.3 V FPGA I/O to 5 V sensor interface without external level shifters. IC Role / Device Role / Timing Role: Passive voltage-tolerant switch leveraging TTL input thresholds and rail-to-rail conduction. Use Value: Eliminates active translation components while preserving <0.25 ns timing alignment. |
Use Scenario: Enabling/disabling USB or RS-232 lines during hot-plug events in industrial controllers. IC Role / Device Role / Timing Role: Fast-enable/disable analog path via OE pin with <5.1 ns enable time. Use Value: Prevents signal glitches during insertion/removal with sub-6 ns transition control. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar FET multiplexer/demultiplexer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74CBTD3384PW | 8-bit, dual 1-of-2 configuration; higher ICC (10 μA), same ron (5–7 Ω), larger TSSOP-24 package. | Supports wider data buses; requires more PCB area and layout revision. | Choose when expanding channel count beyond 4 bits without changing topology. |
| 74LVC1G3157DP | Single-channel, SC-70-6 package; lower VCC range (1.65–5.5 V); ron = 6–10 Ω; tpd = 0.5 ns. | Used for point-to-point switching where density and low voltage operation are critical. | Prefer for ultra-compact designs needing only one switch with 1.65 V compatibility. |
Compared with SN74CBT3257PW, SN74CBTD3384PW offers double channel count at cost of board space and power, while 74LVC1G3157DP trades integration for size and voltage flexibility-neither is pin-compatible, requiring schematic and layout updates.
Availability
SN74CBT3257PW is available at Aetrix Electronics and suitable for industrial automation interfaces, test equipment signal routing, and embedded system bus isolation requiring stable component supply across extended temperature ranges.
Supply support for SN74CBT3257PW 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 company headquartered in Dallas, Texas, specializing in analog, embedded processing, and connectivity technologies since 1930.
The SN74CBT3257PW belongs to TI's CBT (Crossbar Bus Transceiver) family, designed specifically for high-speed, low-distortion digital signal routing in backplane, motherboard, and instrumentation applications.
FAQ
What is the maximum continuous current rating per channel for the SN74CBT3257PW?
The SN74CBT3257PW supports a continuous channel current of 128 mA per switch, verified under absolute maximum ratings. This allows robust signal routing in 5 V digital buses with margin for transient overloads. The device maintains 5–7 Ω on-resistance across this range, ensuring predictable voltage drop and thermal behavior in sustained operation.
Does the SN74CBT3257PW support bidirectional signal flow?
Yes, the SN74CBT3257PW supports fully bidirectional analog and digital signal flow between A and B ports. Its FET-based architecture imposes no directionality-signals pass equally well from A to B1/B2 or B1/B2 to A, making it ideal for bus-sharing and hot-swap applications where signal polarity must remain transparent.
What is the thermal performance of the SN74CBT3257PW in its TSSOP-16 package?
The SN74CBT3257PW has a junction-to-ambient thermal impedance (θJA) of 108°C/W in the PW (TSSOP-16) package, measured per JESD 51-7. This value reflects standard PCB mounting with no copper pour; adding thermal vias or ground plane area can reduce effective θJA by 20–30%, supporting reliable operation at full load within −40°C to +85°C ambient.
Can the SN74CBT3257PW operate from a 3.3 V supply?
No-the SN74CBT3257PW is specified for 4 V to 5.5 V operation only. At 3.3 V, the internal FETs do not fully enhance, resulting in elevated on-resistance (>20 Ω) and unreliable switching. For 3.3 V systems, consider TI's SN74LVC1G3157 or similar LVC-family devices explicitly rated down to 1.65 V.
How does the OE pin function in the SN74CBT3257PW?
The OE (output enable) pin on the SN74CBT3257PW is active-low: when OE = low, the selected A–B path conducts based on S input; when OE = high, all four switches open simultaneously, isolating all A and B terminals regardless of S state. This provides fast, synchronous channel disable with 5.5 ns disable time (tdis), critical for bus arbitration and power sequencing.
SN74CBT3257PW Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74CBT
- Package/Case:
- 16-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Bulk
- 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-TSSOP
SN74CBT3257PW FAQ
1.How can I place an order for SN74CBT3257PW through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74CBT3257PW 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 SN74CBT3257PW reliable?
The price and inventory of SN74CBT3257PW are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74CBT3257PW is usually 5 days.
3.What payment methods are accepted for SN74CBT3257PW?
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SN74CBT3257PW orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74CBT3257PW 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 SN74CBT3257PW?
For technical support, including SN74CBT3257PW datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74CBT3257PW requirements.
6.How does Aetrix verify that SN74CBT3257PW is sourced from the original manufacturer or authorized distributors?
All SN74CBT3257PW 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 SN74CBT3257PW meets industry standards.
7.What is the process for return or replacement of SN74CBT3257PW?
All SN74CBT3257PW units undergo pre-shipment inspection (PSI). If there is an issue with SN74CBT3257PW, 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 SN74CBT3257PW part is unused and in its original packaging.
Return procedure for SN74CBT3257PW:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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