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Texas Instruments SN74CBT3257DBQRG4
- Part No.:
- SN74CBT3257DBQRG4
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-SSOP (0.154", 3.90mm Width)
- Datasheet:
-
SN74CBT3257DBQRG4.pdf
- Description:
- IC MUX/DEMUX 4 X 2:1 16SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,344
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Product details
Overview
SN74CBT3257DBQRG4 from Texas Instruments is a 4-bit 1-of-2 FET multiplexer/demultiplexer with 5 Ω 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 operates from −40°C to 85°C and is used in high-speed data routing applications such as bus isolation and signal switching in digital logic systems.
For engineers reviewing the SN74CBT3257DBQRG4 datasheet, SN74CBT3257DBQRG4 pinout, SN74CBT3257DBQRG4 application, or SN74CBT3257DBQRG4 equivalent, key selection criteria include on-resistance matching across channels, OE/S-controlled bidirectional switching, low capacitive loading (Cio(OFF) = 4 pF), and SSOP-16 package compatibility with legacy board layouts.
Technical Context
The SN74CBT3257DBQRG4 implements four independent bidirectional analog/digital switches controlled by a shared select (S) and output-enable (OE) input. Each switch connects one A-terminal to either B1 or B2 based on S state when OE is low.
Its FET-based architecture delivers rail-to-rail signal handling, 128 mA continuous channel current capability, and minimal charge injection - enabling clean switching of TTL/CMOS logic levels and low-voltage analog signals without level translation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| On-state resistance (ron) | 5–7 Ω at 4.5 V - ensures minimal voltage drop and signal distortion during high-speed switching. |
| Propagation delay (tpd) | 0.25 ns typical at VCC = 5 V - supports >1 GHz data rate routing in synchronous logic paths. |
| Off-state capacitance (Cio(OFF)) | 4 pF - limits crosstalk and maintains signal integrity when adjacent channels are inactive. |
| Supply voltage range | 4 V to 5.5 V - compatible with standard 5 V TTL and mixed-voltage I/O domains. |
| Control input thresholds | VIH = 2 V, VIL = 0.8 V - guarantees reliable recognition of TTL logic levels without external biasing. |
| Operating temperature | −40°C to +85°C - qualified for industrial-grade embedded and communications equipment. |
Pinout & Package
SN74CBT3257DBQRG4 uses a 16-pin SSOP (Shrink Small-Outline Package) with 0.65 mm lead pitch and 2.0 mm max height. Pin 1 is located at the top-left corner with a beveled edge indicator.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2, 3, 4, 5, 6, 13, 14, 15, 16 | A/B port terminals (1A–4A, 1B1–4B2) | Bidirectional signal paths; each A pin routes to corresponding B1 or B2 based on S and OE state. |
| 7 | GND | Power ground reference for internal FET bias and noise suppression. |
| 8 | VCC | Positive supply (4–5.5 V); powers internal switch drivers and level translators. |
| 9 | OE | Active-low output enable; high-Z state disables all switches regardless of S value. |
| 10 | S | Select control; determines whether A ports connect to B1 (S = L) or B2 (S = H). |
Key Features
| Feature | Design Value |
|---|---|
| Low on-resistance matching | ≤2 Ω variation between channels - ensures uniform timing and amplitude across all 4 bits. |
| TTL-compatible control interface | No pull-up/pull-down required - directly interfaces with 74LS, 74HC, and microcontroller GPIOs. |
| Bidirectional signal flow | No direction pin needed - same terminal serves as input or output depending on system context. |
| Break-before-make switching | Guaranteed isolation during transition - prevents momentary shorting between B1 and B2 buses. |
| Low input/output capacitance | Ci = 3.5 pF, Cio(OFF) = 4 pF - minimizes loading on driving sources and preserves edge rates. |
Applications
| PCI Bus Isolation | Memory Address Multiplexing |
|---|---|
|
Use Scenario: Isolating PCI address/data lines between two bus masters to prevent contention during arbitration. IC Role / Device Role / Timing Role: Bidirectional 1-of-2 switch enabling dynamic routing of AD[31:0] lines under host control. Use Value: 5 Ω Ron and 0.25 ns tpd maintain signal integrity at 33 MHz PCI clock rates without added buffers. |
Use Scenario: Sharing a single address bus among multiple memory banks using time-multiplexed access. IC Role / Device Role / Timing Role: 4-bit demux selecting between Bank A and Bank B address latches via S and OE. Use Value: Matched channel Ron ensures equal setup/hold timing margins across all address bits. |
| Test Equipment Signal Routing | Digital Logic Prototyping |
|
Use Scenario: Reconfiguring DUT signal paths in automated test fixtures without manual jumper changes. IC Role / Device Role / Timing Role: High-speed analog/digital switch matrix controlled by FPGA GPIOs. Use Value: 4 pF Cio(OFF) prevents leakage coupling between unselected channels during parallel testing. |
Use Scenario: Adapting legacy 74-series logic designs to new PCB layouts requiring signal reassignment. IC Role / Device Role / Timing Role: Logic-level translator and path selector replacing discrete transistor switches. Use Value: TTL-compatible VIH/VIL eliminates need for level-shifting resistors in breadboard or prototype systems. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar FET multiplexer/demultiplexer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74CBTD3384DBQR | 8-bit, 2.5 V–5.5 V supply, higher Ron (7–10 Ω), 3-state outputs only (no B1/B2 selection) | Supports wider voltage range but lacks dual-B port flexibility; suited for simple bus buffering, not multiplexing. | Choose when needing more channels and voltage flexibility, but accept loss of 1-of-2 routing capability. |
| 74LVC1G3157DCKR | Single-channel, 1.65–5.5 V, Ron = 6 Ω, no shared S/OE control - requires per-channel logic. | Requires four separate devices and additional glue logic to replicate 4-bit function; increases board area and routing complexity. | Prefer only for ultra-low-power or space-constrained single-line switching where full 4-bit integration is unnecessary. |
Compared with SN74CBT3257DBQRG4, SN74CBTD3384DBQR offers greater channel count and voltage range but removes the critical 1-of-2 B-port selection, while 74LVC1G3157DCKR sacrifices integration density and control simplicity - making SN74CBT3257DBQRG4 optimal for compact, TTL-synchronized 4-bit routing tasks.
Availability
SN74CBT3257DBQRG4 is available at Aetrix Electronics and suitable for industrial control backplanes, test instrumentation signal routing, and legacy 5 V digital system upgrades requiring stable component supply and long-term obsolescence mitigation.
Supply support for SN74CBT3257DBQRG4 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 logic solutions, with over 90 years of innovation in industrial, automotive, and communications markets.
The SN74CBT3257DBQRG4 belongs to TI's CBT (Crossbar TTL) logic family, designed specifically for high-speed, low-distortion signal routing in 5 V digital systems where minimal propagation delay and precise on-resistance matching are critical.
FAQ
What is the maximum continuous current rating per channel for SN74CBT3257DBQRG4?
The SN74CBT3257DBQRG4 supports up to 128 mA continuous channel current per switch path. This rating applies under recommended operating conditions (VCC = 4–5.5 V, TA = −40°C to 85°C) and ensures reliable conduction without thermal derating in typical 5 V logic routing applications. Exceeding this limit risks parametric shift or long-term reliability degradation.
Does SN74CBT3257DBQRG4 support bidirectional signal flow on all channels?
Yes, SN74CBT3257DBQRG4 supports true bidirectional operation on all four A/B switch pairs. There is no dedicated input or output pin - signal direction is determined entirely by external circuitry, enabling flexible use in bus arbitration, loopback testing, and reconfigurable interconnects without redesigning signal paths.
Can SN74CBT3257DBQRG4 operate with a 3.3 V supply?
No, SN74CBT3257DBQRG4 is not specified for 3.3 V operation. Its recommended supply range is 4 V to 5.5 V, and absolute maximum ratings define VCC down to −0.5 V but do not guarantee functionality below 4 V. For 3.3 V systems, consider TI's LVC or AUP logic families instead.
What is the function of the OE and S pins on SN74CBT3257DBQRG4?
On SN74CBT3257DBQRG4, OE (pin 9) is an active-low output enable that disconnects all A–B paths when high, placing them in high-impedance state. S (pin 10) selects the destination: when OE is low, S = low connects each A port to its B1 terminal, and S = high connects it to B2. Both controls operate asynchronously with no internal clocks.
Is SN74CBT3257DBQRG4 pin-compatible with other packages in the same family?
Yes, SN74CBT3257DBQRG4 shares identical pinout and electrical behavior with SN74CBT3257D (SOIC), SN74CBT3257PW (TSSOP), and SN74CBT3257RGYR (QFN). All variants use the same 16-pin functional mapping and timing specifications, allowing direct substitution across packages when board layout permits mechanical fit.
SN74CBT3257DBQRG4 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
SN74CBT3257DBQRG4 FAQ
1.How can I place an order for SN74CBT3257DBQRG4 through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74CBT3257DBQRG4 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 SN74CBT3257DBQRG4 reliable?
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5.How can I obtain technical support or documentation for SN74CBT3257DBQRG4?
For technical support, including SN74CBT3257DBQRG4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74CBT3257DBQRG4 requirements.
6.How does Aetrix verify that SN74CBT3257DBQRG4 is sourced from the original manufacturer or authorized distributors?
All SN74CBT3257DBQRG4 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 SN74CBT3257DBQRG4 meets industry standards.
7.What is the process for return or replacement of SN74CBT3257DBQRG4?
All SN74CBT3257DBQRG4 units undergo pre-shipment inspection (PSI). If there is an issue with SN74CBT3257DBQRG4, 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 SN74CBT3257DBQRG4 part is unused and in its original packaging.
Return procedure for SN74CBT3257DBQRG4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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