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Texas Instruments SN74CBT3245DW
- Part No.:
- SN74CBT3245DW
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- -
- Datasheet:
-
SN74CBT3245DW.pdf
- Description:
- BUS DRIVER
- Quantity:
- Payment:
- Shipping:
Inventory:21,000
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Product details
Overview
SN74CBT3245DW from Texas Instruments is an octal bus switch IC with standard '245-type pinout, 5-Ω on-state resistance, TTL-compatible control inputs, and operation from –40°C to 85°C. It functions as a bidirectional 8-bit analog/digital signal path selector in data routing, level-shifting, and bus isolation applications.
For engineers reviewing the SN74CBT3245DW datasheet, SN74CBT3245DW pinout, SN74CBT3245DW application, or SN74CBT3245DW equivalent, key selection criteria include on-resistance (5–7 Ω), propagation delay (0.25 ns typ), high-impedance isolation during disable, ±5 µA input leakage, and DW-package thermal rating (1.6 W at 55°C).
Technical Context
The SN74CBT3245DW implements a single 8-bit bidirectional switch array controlled by one active-low output enable (OE) input. Its BiCMOS process delivers low ron and fast switching without internal latching or direction control logic.
It operates with VCC from 4 V to 5.5 V and supports rail-to-rail analog/digital signal pass-through between ports A and B when enabled. No internal pull-ups, level translators, or ESD protection beyond absolute max ratings are integrated.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 4 V to 5.5 V - Ensures compatibility with 5-V TTL and mixed-voltage system rails. |
| ron (typ) | 5 Ω - Enables minimal voltage drop and signal distortion for ≤128 mA channel current. |
| tpd (typ) | 0.25 ns - Supports high-speed data routing in memory buffers and backplane interfaces. |
| II (max) | ±5 µA - Guarantees low static power draw and stable control input behavior across temperature. |
| Cio(OFF) | 6 pF - Limits capacitive coupling between ports during disable, critical for signal integrity. |
| Operating Temp | –40°C to 85°C - Qualified for industrial-grade embedded and communications equipment. |
Pinout & Package
SN74CBT3245DW uses a 20-pin SOIC (DW) package with 0.300-inch body width and standard '245 pinout. Pin 1 is NC (no connect); pins 2–9 are port A (A1–A8); pin 10 is GND; pin 11 is VCC; pin 12 is OE; pins 13–20 are port B (B1–B8).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (NC) | No-connect terminal | Not internally bonded; must be left unconnected per TI design. |
| 2–9 (A1–A8) | Port A I/O | Bidirectional analog/digital signal terminals; electrically identical to B-side when switch is on. |
| 10 (GND) | Ground reference | Primary return path for VCC and signal currents; requires low-impedance PCB connection. |
| 11 (VCC) | Power supply | Supplies BiCMOS switch core; bypass capacitor (0.1 µF) required near pin. |
| 12 (OE) | Active-low enable | Drives switch ON (A↔B connected) when low; high-impedance isolation when high. |
| 13–20 (B1–B8) | Port B I/O | Matched bidirectional terminals; no internal directionality or buffering. |
Key Features
| Feature | Design Value |
|---|---|
| 5-Ω typical on-resistance | Minimizes insertion loss and timing skew in high-frequency digital and analog signal paths. |
| 0.25-ns typical propagation delay | Enables use in >1-GHz data routing without added latency or jitter accumulation. |
| TTL-compatible control inputs | Accepts standard 5-V logic thresholds (VIL ≤ 0.8 V, VIH ≥ 2 V) without external level shifters. |
| High-impedance OFF state | Provides >1012 Ω isolation between ports, preventing bus contention and crosstalk. |
Applications
| Memory Subsystem Buffering | Hot-Swap Backplane Interface |
|---|---|
Use Scenario: Isolating DRAM address/data buses during memory module insertion/removal in server blade systems. IC Role / Device Role / Timing Role: Bidirectional signal gate enabling/disabling bus connectivity under system controller command. Use Value: Prevents bus contention and data corruption using <10 ns enable/disable times and 6 pF OFF-state capacitance. | Use Scenario: Routing configuration signals between hot-pluggable I/O cards and host controller in telecom chassis. IC Role / Device Role / Timing Role: Low-latency, rail-to-rail analog switch for SMBus, JTAG, or GPIO lines. Use Value: Maintains signal fidelity with 5 Ω ron and 0.25 ns tpd, avoiding timing violations in multi-card synchronization. |
| Legacy Bus Level Translation | Test Equipment Signal Multiplexing |
Use Scenario: Interfacing 3.3-V microcontrollers to 5-V peripheral buses without dedicated level shifters. IC Role / Device Role / Timing Role: Passive bidirectional voltage translator leveraging VCC-referenced switch conduction. Use Value: Eliminates need for active translators via rail-to-rail pass-through and TTL-compatible OE control. | Use Scenario: Selecting one of eight sensor inputs to a shared ADC channel in automated test fixtures. IC Role / Device Role / Timing Role: Low-distortion analog multiplexer with matched A/B channel impedance. Use Value: Delivers <0.1% gain error and sub-ns channel switching due to symmetric 5–7 Ω ron matching. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal bus switch applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74CBTD3384DW | Includes 5-V tolerant inputs and higher drive strength; ron = 4 Ω typ; supports 3.3-V/5-V mixed-mode operation. | Required where input voltage exceeds VCC (e.g., 5-V signals into 3.3-V domain). | Select when interfacing legacy 5-V logic to modern low-voltage controllers without external clamping. |
| QS3245M | Functionally equivalent per datasheet; same pinout, ron, and timing; manufactured by Fairchild (now ON Semiconductor). | No functional deviation; used where second-source qualification is mandated. | Choose for supply chain diversification while retaining identical electrical and mechanical behavior. |
Compared with SN74CBT3245DW, SN74CBTD3384DW adds voltage tolerance at marginally higher cost and power, while QS3245M provides identical performance with alternate sourcing-neither offers pin-to-pin replacement without verification of board-level decoupling and layout constraints.
Availability
SN74CBT3245DW is available at Aetrix Electronics and suitable for memory subsystem buffering, hot-swap backplane interface, and legacy bus level translation requiring stable component supply and industrial temperature support.
Supply support for SN74CBT3245DW 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 U.S.-based semiconductor company founded in 1930, specializing in analog, embedded processing, and logic solutions for industrial, automotive, and communications markets.
The SN74CBT3245DW belongs to TI's CBT (Crosspoint Bus Transceiver) logic family, designed for high-speed, low-distortion signal routing in bus-hold-free, non-latching applications where minimal propagation delay and low on-resistance are critical.
FAQ
What is the maximum continuous current per channel for the SN74CBT3245DW?
The SN74CBT3245DW supports up to 128 mA continuous channel current per switch path, as specified in its absolute maximum ratings. This rating assumes proper PCB thermal design and ambient temperature ≤55°C. Exceeding this current may cause irreversible junction heating or parametric shift. The SN74CBT3245DW must be operated within its recommended VCC range (4 V to 5.5 V) to maintain this current capability.
Does the SN74CBT3245DW require external pull-up or pull-down resistors on its A or B ports?
No, the SN74CBT3245DW does not integrate internal pull-up or pull-down resistors on A or B ports. These ports are purely passive bidirectional connections with no bias circuitry. External termination must be provided by the system design if DC bias or bus idle-state control is required. The SN74CBT3245DW relies entirely on external circuitry for signal conditioning and termination.
Can the SN74CBT3245DW operate with a 3.3-V supply voltage?
No, the SN74CBT3245DW is not rated for 3.3-V operation. Its recommended VCC range is 4 V to 5.5 V, and operation below 4 V violates the manufacturer's specifications. Attempting to power the SN74CBT3245DW at 3.3 V may result in undefined switching behavior, increased ron, or failure to meet timing parameters. Use SN74CB3Q3245 or similar 3.3-V-optimized variants instead.
What is the function of the NC (no-connect) pin on the SN74CBT3245DW?
Pin 1 of the SN74CBT3245DW is designated NC (no connect) and is not internally bonded to any die structure. It must remain unconnected on the PCB-neither tied to VCC, GND, nor left floating with unintended coupling. This pin exists for mechanical symmetry and package compatibility; connecting it risks violating TI's layout guidance and may affect thermal or electrical performance of the SN74CBT3245DW.
How does the SN74CBT3245DW handle signal directionality between ports A and B?
The SN74CBT3245DW provides fully bidirectional signal conduction: when OE is low, signals pass identically from A to B or B to A with matched 5–7 Ω ron and 0.25 ns tpd. There is no internal direction control, driver/receiver asymmetry, or built-in bus arbitration. Direction is determined solely by external source/sink placement-making the SN74CBT3245DW ideal for passive bus isolation and multiplexing where signal flow is externally managed.
SN74CBT3245DW Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- *
- Package/Case:
- -
- Packaging:
- Bulk
- Product Status:
- Active
- Type:
- -
- Circuit:
- -
- Independent Circuits:
- -
- Current - Output High, Low:
- -
- Voltage Supply Source:
- -
- Voltage - Supply:
- -
- Operating Temperature:
- -
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- -
- Supplier Device Package:
- -
SN74CBT3245DW FAQ
1.How can I place an order for SN74CBT3245DW through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74CBT3245DW 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 SN74CBT3245DW reliable?
The price and inventory of SN74CBT3245DW are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74CBT3245DW is usually 5 days.
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SN74CBT3245DW orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74CBT3245DW 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 SN74CBT3245DW?
For technical support, including SN74CBT3245DW datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74CBT3245DW requirements.
6.How does Aetrix verify that SN74CBT3245DW is sourced from the original manufacturer or authorized distributors?
All SN74CBT3245DW 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 SN74CBT3245DW meets industry standards.
7.What is the process for return or replacement of SN74CBT3245DW?
All SN74CBT3245DW units undergo pre-shipment inspection (PSI). If there is an issue with SN74CBT3245DW, 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 SN74CBT3245DW part is unused and in its original packaging.
Return procedure for SN74CBT3245DW:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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