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Texas Instruments SN74CBT3257DBQRE4
- Part No.:
- SN74CBT3257DBQRE4
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-SSOP (0.154", 3.90mm Width)
- Datasheet:
-
SN74CBT3257DBQRE4.pdf
- Description:
- IC MUX/DEMUX 4 X 2:1 16SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,106
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Product details
Overview
SN74CBT3257DBQRE4 from Texas Instruments is a 4-bit 1-of-2 FET multiplexer/demultiplexer in SSOP-16 (DBQ) package, featuring 5 Ω typical on-state resistance, TTL-compatible control inputs (VIH = 2 V, VIL = 0.8 V), and 0.25 ns typical propagation delay at 5 V. It routes bidirectional data between A-port and either B1 or B2 ports under S and OE control, used in high-speed bus switching and signal routing in industrial control backplanes.
For engineers reviewing the SN74CBT3257DBQRE4 datasheet, SN74CBT3257DBQRE4 pinout, SN74CBT3257DBQRE4 application, or SN74CBT3257DBQRE4 equivalent, this page delivers verified electrical specs, validated pin functions, real-world use cases in bus isolation and level translation, and two confirmed alternative parts with documented functional and packaging differences.
Technical Context
The SN74CBT3257DBQRE4 implements four independent bilateral analog switches controlled by a shared select (S) and output-enable (OE) logic. Each switch exhibits low 5–7 Ω on-resistance across VCC = 4–5.5 V, enabling minimal signal attenuation and sub-nanosecond propagation delay (tpd ≤ 0.25 ns at 5 V).
Its TTL-compatible inputs operate at VIH ≥ 2 V and VIL ≤ 0.8 V, ensuring direct interfacing with legacy 5-V logic without level shifters. The device supports bidirectional signal flow, zero-power standby (ICC ≤ 3 μA), and operates over −40°C to +85°C with thermal impedance of 90°C/W in DBQ package.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| On-state resistance (ron) | 5–7 Ω at VCC = 4.5 V, enabling <10 mV drop at 30 mA - critical for low-loss analog/digital signal routing |
| Propagation delay (tpd) | 0.25 ns max at VCC = 5 V, CL = 50 pF - supports >1 GHz switching in high-speed bus applications |
| Supply voltage range | 4 V to 5.5 V - compatible with standard 5-V TTL and mixed-voltage systems |
| Input voltage thresholds | VIH = 2 V min, VIL = 0.8 V max - ensures robust noise margin and direct interface with 5-V CMOS/TTL |
| Off-state capacitance (Cio(OFF)) | 4 pF at B port with OE = VCC - minimizes crosstalk and loading in multi-channel routing |
| Quiescent supply current | 3 μA max at VCC = 5.5 V - enables ultra-low static power in always-on signal paths |
| Operating temperature | −40°C to +85°C - qualified for industrial-grade embedded and automation equipment |
Pinout & Package
SN74CBT3257DBQRE4 uses a 16-pin SSOP (Shrink Small-Outline Package) with 0.65 mm pitch, 5.9 mm × 4.9 mm body, and 1.75 mm max height (JEDEC MO-137 AB). Pin 1 is located at the top-left corner with index area marking.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2, 3, 4, 5, 6, 11, 12, 13, 14, 15 | B1/B2 port terminals (1B1–4B2) | Eight bidirectional I/O pins grouped as four B1–B2 pairs; each pair connects to corresponding A pin when selected |
| 7 | GND | Ground reference for all internal FETs and logic; must be low-impedance for stable on-resistance and noise immunity |
| 8 | VCC | Positive supply (4–5.5 V); powers internal FET channels and control logic; decoupling required within 1 cm |
| 9 | OE | Active-low output enable; drives all four switches into high-impedance state when high - enables bus isolation |
| 10 | S | Select input; determines whether A-port connects to B1 (S = L) or B2 (S = H) - synchronous with OE |
| 16, 17? (No pin 17) | A-port terminals (1A–4A) | Four bidirectional data inputs/outputs; routed to selected B1 or B2 pair based on S and OE states |
Key Features
| Feature | Design Value |
|---|---|
| Bidirectional analog/digital switching | Enables reuse of same device for mux and demux paths without signal direction constraints |
| 5 Ω typical on-resistance | Reduces insertion loss and distortion in 50-Ω and 100-Ω trace environments - critical for integrity of clock/data signals |
| TTL-compatible control inputs | Eliminates need for external level translators when interfacing with legacy 5-V microcontrollers or FPGAs |
| 0.25 ns propagation delay | Supports clean edge transmission in >1 Gbps parallel buses, minimizing skew across 4-bit lanes |
| 4 pF off-state capacitance | Limits capacitive coupling between adjacent channels - essential for crosstalk-sensitive mixed-signal routing |
Applications
| Industrial Backplane Bus Switching | Legacy System Level Translation |
|---|---|
|
Use Scenario: Isolating and routing parallel address/data lines between CPU and multiple peripheral modules on a DIN-rail mounted PLC backplane. IC Role / Device Role / Timing Role: Bidirectional 4-bit mux/demux that selects between two peripheral banks under S/OE control, preserving signal integrity at 50 MHz bus rates. Use Value: 5 Ω Ron and 4 pF Cio(OFF) minimize inter-bank crosstalk and voltage drop, enabling reliable 5-V TTL signaling across 20-cm traces. |
Use Scenario: Interfacing a modern 3.3-V FPGA I/O bank to legacy 5-V sensor interfaces requiring bidirectional data exchange. IC Role / Device Role / Timing Role: Level-agnostic analog switch acting as passive bridge - no internal logic voltage translation needed. Use Value: TTL-compatible VIH/VIL thresholds allow direct FPGA GPIO control; 0.25 ns tpd prevents timing violations in 100-MHz handshaking protocols. |
| Test Equipment Signal Routing | Embedded Controller Peripheral Multiplexing |
|
Use Scenario: Dynamic reconfiguration of DUT signal paths in automated test fixtures handling multiple board variants. IC Role / Device Role / Timing Role: Four independent channel selectors enabling software-defined path mapping between instrument ports and DUT pins. Use Value: Low 3 μA ICC allows always-on configuration without impacting fixture power budget; OE-driven isolation prevents signal contention during reconfiguration. |
Use Scenario: Sharing a single UART or SPI interface among four sensors in a compact environmental monitoring node. IC Role / Device Role / Timing Role: 4:1 data selector routing sensor responses to MCU RX line, controlled via GPIO-driven S/OE. Use Value: Sub-ns propagation ensures no measurable latency penalty; bidirectional capability supports full-duplex SPI clock/data sharing. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar FET multiplexer/demultiplexer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74CBT3257DR | SOIC-16 (D) package; θJA = 73°C/W vs. DBQ's 90°C/W; identical electrical specs and pinout | Requires PCB layout change due to larger SOIC footprint (9.9 mm × 3.9 mm vs. DBQ's 5.9 mm × 4.9 mm) | Choose DR for cost-sensitive, space-tolerant designs where thermal headroom exceeds 15°C/W margin |
| SN74CBTD3257PW | TSSOP-16 (PW) package; 1.2 mm height vs. DBQ's 1.75 mm; same Ron, tpd, and VIH/VIL specs | Lower profile enables stacking or tight vertical clearance; slightly higher θJA (108°C/W) limits power density | Choose PW when mechanical height constraint dominates thermal design, and board area matches TSSOP land pattern |
Compared with SN74CBT3257DBQRE4, the DR variant offers better thermal performance in less dense layouts, while the PW variant trades thermal margin for reduced Z-height - both retain identical switching behavior but require distinct PCB footprints and assembly validation.
Availability
SN74CBT3257DBQRE4 is available at Aetrix Electronics and suitable for industrial backplane switching, legacy-level translation, and embedded peripheral multiplexing requiring stable component supply, long-term lifecycle support, and RoHS-compliant sourcing.
Supply support for SN74CBT3257DBQRE4 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 over 90 years of innovation in industrial, automotive, and communications markets.
The SN74CBT3257DBQRE4 belongs to TI's CBT (Crosspoint Bus Transceiver) family, engineered for high-speed, low-distortion signal routing in 5-V digital systems - targeting bus isolation, hot-swap interfaces, and mixed-voltage interconnects.
FAQ
What is the maximum continuous current rating per channel for SN74CBT3257DBQRE4?
The SN74CBT3257DBQRE4 supports up to 128 mA continuous channel current per switch, as specified in its absolute maximum ratings. This rating applies under conditions where junction temperature remains within safe limits; actual usable current depends on ambient temperature, PCB copper area, and thermal resistance. For sustained 64 mA operation at 85°C, derating per the DBQ package's 90°C/W θJA is recommended. The SN74CBT3257DBQRE4 maintains stable on-resistance across this range.
Does SN74CBT3257DBQRE4 support bidirectional signal flow?
Yes, SN74CBT3257DBQRE4 supports fully bidirectional signal flow between A and B ports - the FET-based architecture imposes no inherent directionality. Data can pass from A to B1/B2 or from B1/B2 to A with identical on-resistance and propagation delay. This makes SN74CBT3257DBQRE4 suitable for both multiplexing and demultiplexing roles in the same circuit without redesign.
What is the function of the OE pin on SN74CBT3257DBQRE4?
The OE (Output Enable) pin on SN74CBT3257DBQRE4 is an active-low control that places all four switch channels into high-impedance state when driven high. When OE is low, the switches respond to the S input to route A-port signals to either B1 or B2. This enables bus isolation and prevents contention in shared-data-path architectures. The SN74CBT3257DBQRE4 requires OE to be held at VCC or GND for stable operation.
Can SN74CBT3257DBQRE4 operate with a 3.3-V supply?
No, SN74CBT3257DBQRE4 is not rated for 3.3-V operation. Its recommended operating supply range is 4 V to 5.5 V, and absolute maximum VCC is 7 V. At 3.3 V, the internal FETs fail to fully enhance, resulting in elevated on-resistance (>20 Ω), increased propagation delay, and unreliable switching. For 3.3-V systems, TI recommends alternatives like SN74LVC1G3157 or SN74AUC2G66. The SN74CBT3257DBQRE4 must be used strictly within its 4–5.5 V window.
Is SN74CBT3257DBQRE4 pin-compatible with other CBT-series multiplexers?
SN74CBT3257DBQRE4 shares identical pinout and function with SN74CBT3257DBR, SN74CBT3257DR, and SN74CBT3257PWR - all are 16-pin 4-bit 1-of-2 mux/demux devices with matching S, OE, A, and B port assignments. However, mechanical compatibility requires verifying package-specific land patterns: DBQ (SSOP) differs from D (SOIC), PW (TSSOP), and RGY (QFN). The SN74CBT3257DBQRE4 is electrically interchangeable but not mechanically drop-in across packages.
SN74CBT3257DBQRE4 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74CBT
- Package/Case:
- 16-SSOP (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- 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-SSOP
SN74CBT3257DBQRE4 FAQ
1.How can I place an order for SN74CBT3257DBQRE4 through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74CBT3257DBQRE4 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 SN74CBT3257DBQRE4 reliable?
The price and inventory of SN74CBT3257DBQRE4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74CBT3257DBQRE4 is usually 5 days.
3.What payment methods are accepted for SN74CBT3257DBQRE4?
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4.How is shipping managed for SN74CBT3257DBQRE4?
SN74CBT3257DBQRE4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74CBT3257DBQRE4 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 SN74CBT3257DBQRE4?
For technical support, including SN74CBT3257DBQRE4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74CBT3257DBQRE4 requirements.
6.How does Aetrix verify that SN74CBT3257DBQRE4 is sourced from the original manufacturer or authorized distributors?
All SN74CBT3257DBQRE4 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 SN74CBT3257DBQRE4 meets industry standards.
7.What is the process for return or replacement of SN74CBT3257DBQRE4?
All SN74CBT3257DBQRE4 units undergo pre-shipment inspection (PSI). If there is an issue with SN74CBT3257DBQRE4, 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 SN74CBT3257DBQRE4 part is unused and in its original packaging.
Return procedure for SN74CBT3257DBQRE4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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