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Home > Products > Integrated Circuits (ICs) > Logic > Signal Switches, Multiplexers, Decoders

Texas Instruments SN74CBT3245ADWR

Name: SN74CBT3245ADWR
Brand: Texas Instruments
SKU: SN74CBT3245ADWR
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: SN74CBT3245ADWR

Manufacturer:: Texas Instruments

Category:: Signal Switches, Multiplexers, Decoders

Package:: 20-SOIC (0.295", 7.50mm Width)

Datasheet:: SN74CBT3245ADWR.pdf

Description:: IC BUS SWITCH 8 X 1:1 20SOIC

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Product details

Overview

SN74CBT3245ADWR from Texas Instruments is an octal FET bus switch IC designed for high-speed TTL-compatible bidirectional data routing between two 8-bit ports (A and B). It features 5-Ω typical on-state resistance, 0.25 ns propagation delay at 5 V, and operates from 4 V to 5.5 V supply. It is used in address/data bus isolation, hot-swap interface buffering, and level-translating I/O expansion circuits.

For engineers reviewing the SN74CBT3245ADWR datasheet, SN74CBT3245ADWR pinout, SN74CBT3245ADWR application, or SN74CBT3245ADWR equivalent, key selection criteria include its low on-resistance switching, standard '245-type pinout compatibility, TTL-level control input thresholds, and guaranteed high-impedance isolation during power sequencing.

Technical Context

The SN74CBT3245ADWR implements eight independent NMOS pass-gate switches with no internal logic inversion or latching. Its output-enable (OE) input controls all eight channels simultaneously: OE low enables bidirectional conduction between A and B ports; OE high places both ports in high-impedance state.

It uses charge-pump-assisted gate drive to maintain low and symmetric on-resistance across the full input voltage range (0–VCC), enabling rail-to-rail analog or digital signal switching without body diode conduction. The device requires no external bias and supports hot-insertion when OE is pulled up to VCC via a resistor.

Key Specifications

Parameter	Value and Actual Design Meaning
Supply Voltage (VCC)	4 V to 5.5 V - Ensures compatibility with 5-V TTL and mixed-voltage systems; operation below 4 V not guaranteed.
On-State Resistance (ron)	5 Ω typical at VCC = 4.5 V - Enables minimal voltage drop (<150 mV at 30 mA) and preserves signal integrity in high-speed buses.
Propagation Delay (tpd)	0.25 ns at VCC = 5 V, CL = 50 pF - Supports >1 GHz effective switching rates in low-capacitance interconnects.
Control Input Thresholds	VIL ≤ 0.8 V, VIH ≥ 2.0 V - Directly interfaces with standard TTL outputs without level-shifting circuitry.
Off-State Capacitance (Cio)	4 pF max - Limits crosstalk and loading on adjacent traces in dense PCB layouts.
Operating Temperature	−40°C to +85°C - Qualified for industrial-grade embedded and communications equipment environments.

Pinout & Package

SN74CBT3245ADWR is housed in a 20-pin SOIC (DW) package measuring 7.5 mm × 12.8 mm × 2.65 mm, with 1.27 mm lead pitch and gull-wing leads. Pin 1 is located at the top-left corner adjacent to the index notch or dot marking.

Pin/Terminal	Circuit Role	Design Meaning
1, 2, 3, 4, 5, 6, 7, 8	A1–A8	Port A bidirectional data terminals - Connect to upstream bus or controller side; electrically identical to B-side when switch is enabled.
9	GND	Ground reference for all internal circuitry and substrate - Must be low-impedance connection to minimize noise coupling.
10	VCC	Positive supply input - Powers internal charge pump and gate drivers; bypass capacitor (0.1 µF) required near pin.
11	OE	Active-low output enable - Driven low to connect A↔B; must be pulled high (e.g., 10 kΩ to VCC) during power-up/down to ensure Hi-Z state.
12, 13, 14, 15, 16, 17, 18, 19	B1–B8	Port B bidirectional data terminals - Connect to downstream bus, memory, or peripheral side; functionally mirrored to A-port.
20	NC	No internal connection - Left unconnected; not bonded or tied internally; may be used as mechanical anchor or keep-out marker.

Key Features

Feature	Design Value
Standard '245 pinout compatibility	Enables drop-in replacement for legacy 74LS245/74HC245 in existing PCB layouts without redesign.
TTL-compatible control inputs	Accepts standard 5-V TTL logic levels directly - eliminates need for external level translators on OE line.
5-Ω typical on-resistance	Reduces insertion loss and timing skew across all eight channels, critical for parallel bus signal matching.
0.25 ns propagation delay	Supports sub-nanosecond edge alignment in high-speed synchronous interfaces such as ISA, LPC, or custom parallel buses.
High-impedance isolation on disable	Guarantees <1 μA leakage between A and B ports when OE is high - prevents back-driving and contention in shared-bus systems.

Applications

PCI Bus Isolation	Memory Address Buffering
Use Scenario: Isolating PCI add-in card address/data lines from motherboard during hot-plug insertion or reset sequences. IC Role / Device Role / Timing Role: Bidirectional bus switch controlled by system reset or slot enable signal to prevent bus contention. Use Value: Eliminates need for discrete MOSFET arrays or complex logic; maintains signal integrity with <0.3 ns delay and 5-Ω R_on.	Use Scenario: Buffering address lines between microcontroller and external SRAM/Flash to reduce capacitive loading and improve timing margin. IC Role / Device Role / Timing Role: Passive, non-inverting bus switch enabling clean address propagation without added clock cycle overhead. Use Value: Delivers 0.25 ns t_pd and 4 pF off-capacitance - minimizes setup/hold time violations in 20+ MHz memory access cycles.
Hot-Swap I/O Expansion	Level-Translating Data Multiplexing
Use Scenario: Enabling safe insertion/removal of I/O daughterboards in industrial PLC backplanes operating at 5 V. IC Role / Device Role / Timing Role: OE-controlled isolation barrier that asserts high-Z state before power sequencing begins. Use Value: Built-in power-up robustness via OE pull-up requirement ensures default isolation - no external sequencer logic needed.	Use Scenario: Multiplexing 3.3-V FPGA I/O with 5-V peripheral devices using shared data bus architecture. IC Role / Device Role / Timing Role: Bidirectional voltage-agnostic switch leveraging FET pass-gate topology for rail-to-rail signal passage. Use Value: 5-Ω R_on and symmetric conduction allow clean 3.3 V ↔ 5 V translation without level-shifter latency or DC bias networks.

PCI Bus Isolation

Memory Address Buffering

Use Scenario: Isolating PCI add-in card address/data lines from motherboard during hot-plug insertion or reset sequences.

IC Role / Device Role / Timing Role: Bidirectional bus switch controlled by system reset or slot enable signal to prevent bus contention.

Use Value: Eliminates need for discrete MOSFET arrays or complex logic; maintains signal integrity with <0.3 ns delay and 5-Ω R_on.

Use Scenario: Buffering address lines between microcontroller and external SRAM/Flash to reduce capacitive loading and improve timing margin.

IC Role / Device Role / Timing Role: Passive, non-inverting bus switch enabling clean address propagation without added clock cycle overhead.

Use Value: Delivers 0.25 ns t_pd and 4 pF off-capacitance - minimizes setup/hold time violations in 20+ MHz memory access cycles.

Hot-Swap I/O Expansion

Level-Translating Data Multiplexing

Use Scenario: Enabling safe insertion/removal of I/O daughterboards in industrial PLC backplanes operating at 5 V.

IC Role / Device Role / Timing Role: OE-controlled isolation barrier that asserts high-Z state before power sequencing begins.

Use Value: Built-in power-up robustness via OE pull-up requirement ensures default isolation - no external sequencer logic needed.

Use Scenario: Multiplexing 3.3-V FPGA I/O with 5-V peripheral devices using shared data bus architecture.

IC Role / Device Role / Timing Role: Bidirectional voltage-agnostic switch leveraging FET pass-gate topology for rail-to-rail signal passage.

Use Value: 5-Ω R_on and symmetric conduction allow clean 3.3 V ↔ 5 V translation without level-shifter latency or DC bias networks.

Equivalent & Alternatives

The following parts are listed as comparable options for similar octal bus switch applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
SN74CBTD3384ADWR	Includes integrated 5-V tolerant level shifters; higher 7-Ω ron; 3.3-V core supply only.	Required when interfacing 3.3-V logic to 5-V buses with automatic voltage translation.	Select when level-shifting capability is mandatory; not pin-compatible due to different pinout and VCCIO requirements.
74LVC245APW	CMOS-based 3-state transceiver; 3.3-V only; 24 mA drive; no true bidirectional passive switching.	Suitable for unidirectional or direction-controlled data flow with active drive strength.	Choose when bus driving capability (not just switching) is needed; incompatible for passive, low-latency, bidirectional use cases.

Compared with SN74CBT3245ADWR, SN74CBTD3384ADWR adds level translation but increases on-resistance and alters pin assignment, while 74LVC245APW provides active drive and direction control but lacks true passive bidirectional transparency and sub-nanosecond latency.

Availability

SN74CBT3245ADWR is available at Aetrix Electronics and suitable for PCI bus isolation, memory address buffering, and hot-swap I/O expansion requiring stable component supply and long-term industrial lifecycle support.

Supply support for SN74CBT3245ADWR 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 SN74CBT3245ADWR belongs to TI's CBT (Crosspoint Bus Transceiver) family, engineered specifically for ultra-low-latency, bidirectional, passive bus switching in high-speed digital systems where signal integrity and timing predictability are critical.

FAQ

What is the maximum continuous current rating per channel for the SN74CBT3245ADWR?

The SN74CBT3245ADWR supports a maximum continuous channel current of 128 mA 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 runaway or parametric shift. Exceeding this value risks permanent degradation of on-resistance and switching lifetime.

Does the SN74CBT3245ADWR require external pull-up resistors on the OE pin?

Yes, the SN74CBT3245ADWR requires an external pull-up resistor on the OE pin to VCC to guarantee high-impedance isolation during power-up and power-down transitions. TI specifies a minimum resistor value based on the driver's current-sinking capability; a 10-kΩ resistor is commonly used and ensures OE remains high until valid VCC is established.

Can the SN74CBT3245ADWR operate with a 3.3-V supply?

No, the SN74CBT3245ADWR is not rated for 3.3-V operation. Its recommended operating supply range is 4 V to 5.5 V, and absolute maximum ratings specify VCC down to −0.5 V but do not guarantee functionality below 4 V. For 3.3-V systems, TI recommends the SN74CBTD3384A or SN74LVC245A as functional alternatives.

Is the SN74CBT3245ADWR pin-compatible with standard 74-series '245 devices?

Yes, the SN74CBT3245ADWR uses the standard '245-type pinout across SOIC (DW), SSOP (DB), TSSOP (PW), and TVSOP (DGV) packages. Pin assignments for A1–A8, B1–B8, OE, VCC, GND, and NC match industry-standard octal transceivers, enabling direct PCB footprint reuse without layout modification.

What is the thermal resistance (θJA) of the SN74CBT3245ADWR in its SOIC (DW) package?

The SN74CBT3245ADWR in the SOIC (DW) package has a junction-to-ambient thermal resistance (θJA) of 58°C/W, measured per JESD 51-7. This value assumes standard JEDEC 2-layer board conditions (1-inch² copper pad, 2 oz Cu). Actual thermal performance depends on PCB copper area, airflow, and nearby heat sources.

SN74CBT3245ADWR Specifications

Product attributes: Attribute value

Manufacturer:: Texas Instruments

Series:: 74CBT

Package/Case:: 20-SOIC (0.295", 7.50mm Width)

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Type:: Bus Switch

Circuit:: 8 x 1:1

Independent Circuits:: 1

Current - Output High, Low:: -

Voltage Supply Source:: Single Supply

Voltage - Supply:: 4V ~ 5.5V

Operating Temperature:: -40°C ~ 85°C

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 20-SOIC

SN74CBT3245ADWR FAQ

1.How can I place an order for SN74CBT3245ADWR through Aetrix?

Please submit a Request for Quotation (RFQ) for SN74CBT3245ADWR 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 SN74CBT3245ADWR reliable?

The price and inventory of SN74CBT3245ADWR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74CBT3245ADWR is usually 5 days.

3.What payment methods are accepted for SN74CBT3245ADWR?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74CBT3245ADWR transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for SN74CBT3245ADWR?

SN74CBT3245ADWR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your SN74CBT3245ADWR 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 SN74CBT3245ADWR?

For technical support, including SN74CBT3245ADWR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74CBT3245ADWR requirements.

6.How does Aetrix verify that SN74CBT3245ADWR is sourced from the original manufacturer or authorized distributors?

All SN74CBT3245ADWR 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 SN74CBT3245ADWR meets industry standards.

7.What is the process for return or replacement of SN74CBT3245ADWR?

All SN74CBT3245ADWR units undergo pre-shipment inspection (PSI). If there is an issue with SN74CBT3245ADWR, 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 SN74CBT3245ADWR part is unused and in its original packaging.

Return procedure for SN74CBT3245ADWR:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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