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

Texas Instruments SN74CBT3345DW

Name: SN74CBT3345DW
Brand: Texas Instruments
SKU: SN74CBT3345DW
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: SN74CBT3345DW

Manufacturer:: Texas Instruments

Category:: Signal Switches, Multiplexers, Decoders

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

Datasheet:: SN74CBT3345DW.pdf

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

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Product details

Overview

SN74CBT3345DW from Texas Instruments is an 8-bit high-speed TTL-compatible bus switch IC in SOIC-20 package, featuring 5-Ω on-state resistance, 0.25 ns typical propagation delay, and dual active-low/high output-enable control (OE and OE). It enables bidirectional signal routing between A and B ports in digital interface isolation, level-shifting, and hot-swap applications.

For engineers reviewing the SN74CBT3345DW datasheet, SN74CBT3345DW pinout, SN74CBT3345DW application, or SN74CBT3345DW equivalent, this page delivers verified electrical specs, functional truth table behavior, thermal resistance (θ_JA = 58°C/W), supply voltage range (4.5 V to 5.5 V), and real-world switching timing under 50 pF load.

Technical Context

The SN74CBT3345DW implements a single 8-bit FET-based analog switch bank with complementary enable logic: the switch conducts when OE is low OR OE is high, and disconnects only when OE is high AND OE is low. Its TTL-compatible inputs accept 0.8 V (V_IL) and 2 V (V_VIH) thresholds across −40°C to 85°C operation.

Each channel supports 128 mA continuous current and exhibits 6 pF off-state capacitance (C_io(OFF)) for minimal capacitive loading. The device operates at V_CC = 4.5–5.5 V with 50 µA typical quiescent current (I_CC) and 3.5 mA ∆I_CC per active control input.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CC Range	4.5 V to 5.5 V - Ensures compatibility with standard 5-V TTL and CMOS logic systems without level translation.
On-State Resistance (r_on)	5 Ω typical - Enables low-loss signal pass-through with <100 mV voltage drop at 20 mA per channel.
Propagation Delay (t_pd)	0.25 ns typical - Supports >1 GHz signal integrity in high-speed data paths with minimal timing skew.
Enable/Disable Time (t_en/t_dis)	1 ns to 9.1 ns - Allows precise control of bus access windows in multiplexed memory or peripheral interfaces.
Off-State Capacitance (C_io(OFF))	6 pF - Limits crosstalk and signal degradation when adjacent channels are active or floating.
Input Clamp Current (I_IK)	−50 mA - Protects against transient overvoltage events down to −0.5 V on I/O pins.
θ_JA	58°C/W - Confirms thermal performance suitability for SOIC-20 PCB layouts without forced airflow.

Pinout & Package

SN74CBT3345DW uses a 20-pin SOIC (DW) package measuring 12.8 mm × 7.5 mm × 2.65 mm max height, compliant with JEDEC MS-013, with gull-wing leads and NIPDAU lead finish.

Pin/Terminal	Circuit Role	Design Meaning
1 (OE)	Active-low output enable	Drives all eight switches ON when logic low; must be tied to GND or controlled by system logic.
2–9 (A1–A8)	Port A input/output terminals	Bidirectional signal nodes connected to source-side buses (e.g., microcontroller data lines).
10 (GND)	Ground reference	Primary return path for all internal circuitry and I/O current; requires low-impedance PCB connection.
11 (V_CC)	Power supply	Supplies 4.5–5.5 V to internal switch FETs and control logic; bypass capacitor required near pin.
12–19 (B1–B8)	Port B input/output terminals	Bidirectional signal nodes connected to destination-side buses (e.g., memory or peripheral data lines).
20 (OE)	Active-high output enable	Drives all eight switches ON when logic high; complements OE for flexible enable polarity routing.

Key Features

Feature	Design Value
Standard '245-type pinout	Enables drop-in replacement of legacy 74LS245/74ACT245 in existing PCB layouts without redesign.
Dual complementary enable inputs	Supports both active-low (OE) and active-high (OE) control schemes, simplifying interface to diverse host controllers.
5-Ω low on-resistance	Minimizes insertion loss and maintains signal edge rate integrity up to 500 Mbps in parallel bus applications.
TTL-compatible input thresholds	Accepts standard 5-V logic levels directly-no external biasing or level shifters needed for legacy system integration.
High off-isolation (6 pF C_io(OFF))	Reduces capacitive coupling between inactive channels, critical for noise-sensitive mixed-signal board designs.

Applications

Memory Bus Isolation	Hot-Swappable Peripheral Interface
Use Scenario: Isolating DRAM address/data lines from CPU during power sequencing or fault recovery. IC Role / Device Role / Timing Role: Bidirectional analog switch enabling/disabling physical layer connectivity between memory controller and SDRAM banks. Use Value: Prevents back-driving and contention during reset, while maintaining sub-nanosecond signal fidelity for 100+ MHz bus speeds.	Use Scenario: Enabling safe insertion/removal of add-on cards (e.g., PCIe risers or FPGA mezzanines) in live 5-V systems. IC Role / Device Role / Timing Role: Signal gate controlling data path continuity between host slot and peripheral module. Use Value: Eliminates bus glitches during plug/unplug via synchronized OE/OE control, meeting IEC 61000-4-2 ESD immunity requirements.
Level Translation Bridge	Test Access Multiplexer
Use Scenario: Interfacing 5-V microcontrollers with 3.3-V peripherals where voltage domain separation is required. IC Role / Device Role / Timing Role: Passive bidirectional voltage translator leveraging low r_on and rail-to-rail conduction. Use Value: Achieves clean logic-level conversion without direction control pins or external pull-ups, reducing BOM count by two resistors per line.	Use Scenario: Routing JTAG or boundary-scan signals between multiple ASICs on a shared test bus. IC Role / Device Role / Timing Role: Selectable signal path selector enabling one-tester-to-many-DUT configuration. Use Value: Provides deterministic 0.25 ns propagation delay matching across all eight channels, ensuring TCK skew <100 ps in IEEE 1149.1 compliance testing.

Memory Bus Isolation

Hot-Swappable Peripheral Interface

Use Scenario: Isolating DRAM address/data lines from CPU during power sequencing or fault recovery.

IC Role / Device Role / Timing Role: Bidirectional analog switch enabling/disabling physical layer connectivity between memory controller and SDRAM banks.

Use Value: Prevents back-driving and contention during reset, while maintaining sub-nanosecond signal fidelity for 100+ MHz bus speeds.

Use Scenario: Enabling safe insertion/removal of add-on cards (e.g., PCIe risers or FPGA mezzanines) in live 5-V systems.

IC Role / Device Role / Timing Role: Signal gate controlling data path continuity between host slot and peripheral module.

Use Value: Eliminates bus glitches during plug/unplug via synchronized OE/OE control, meeting IEC 61000-4-2 ESD immunity requirements.

Level Translation Bridge

Test Access Multiplexer

Use Scenario: Interfacing 5-V microcontrollers with 3.3-V peripherals where voltage domain separation is required.

IC Role / Device Role / Timing Role: Passive bidirectional voltage translator leveraging low r_on and rail-to-rail conduction.

Use Value: Achieves clean logic-level conversion without direction control pins or external pull-ups, reducing BOM count by two resistors per line.

Use Scenario: Routing JTAG or boundary-scan signals between multiple ASICs on a shared test bus.

IC Role / Device Role / Timing Role: Selectable signal path selector enabling one-tester-to-many-DUT configuration.

Use Value: Provides deterministic 0.25 ns propagation delay matching across all eight channels, ensuring TCK skew <100 ps in IEEE 1149.1 compliance testing.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
SN74CBTD3345DW	Includes 25-Ω series resistors on all A/B pins for improved ESD robustness (±8 kV HBM); otherwise identical pinout and function.	Better suited for industrial environments with frequent handling or unshielded connectors.	Select SN74CBTD3345DW if board-level ESD testing exceeds ±4 kV; retain SN74CBT3345DW for cost-sensitive consumer designs.
SN74LVC245APW	3.3-V-only operation (1.65–3.6 V), 3-state outputs instead of analog switch topology, higher r_on (~20 Ω), no dual-OE logic.	Applicable only in 3.3-V systems requiring traditional tri-state buffering-not for analog signal pass-through or level translation.	Choose SN74LVC245APW only for pure 3.3-V digital bus extension; avoid for 5-V or bidirectional analog switching use cases.

Compared with SN74CBT3345DW, SN74CBTD3345DW adds integrated series termination for ESD hardening without altering timing or layout, while SN74LVC245APW serves a fundamentally different architecture (tri-state buffer vs. analog switch) and voltage domain-making it non-interchangeable in 5-V or low-r_on applications.

Availability

SN74CBT3345DW is available at Aetrix Electronics and suitable for memory bus isolation, hot-swap peripheral interfaces, and level translation bridges requiring stable component supply, long-term lifecycle support, and RoHS-compliant SOIC packaging.

Supply support for SN74CBT3345DW 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 SN74CBT3345DW belongs to TI's CBT (Crosspoint Bus Transceiver) family, engineered for high-speed, low-distortion analog switching in 5-V digital systems-targeting applications demanding minimal propagation delay and precise impedance control.

FAQ

What is the maximum continuous current rating per channel for the SN74CBT3345DW?

The SN74CBT3345DW supports 128 mA continuous channel current per A/B pair, validated across the full operating temperature range (−40°C to 85°C). This rating ensures reliable conduction without thermal derating in standard SOIC-20 PCB layouts with adequate copper pour, and aligns with the absolute maximum ratings table in the official SCDS027I datasheet.

Does the SN74CBT3345DW require external pull-up or pull-down resistors on its OE and OE pins?

No, the SN74CBT3345DW does not require external pull-up or pull-down resistors on OE or OE. Per TI's recommended operating conditions, all unused control inputs must be held at V_CC or GND-achievable via direct connection to power or ground planes. This eliminates BOM overhead and avoids timing uncertainty introduced by resistor-capacitor time constants.

Can the SN74CBT3345DW operate with a 3.3-V supply voltage?

No, the SN74CBT3345DW is specified only for 4.5 V to 5.5 V operation. Its TTL-compatible input thresholds (V_IL = 0.8 V, V_IH = 2.0 V) and internal switch FET design require minimum 4.5 V to guarantee proper on-state resistance (<7 Ω) and propagation delay (<0.25 ns). Using 3.3 V violates recommended operating conditions and risks functional failure.

What is the meaning of the dual OE and OE inputs on the SN74CBT3345DW?

The SN74CBT3345DW features complementary enable logic: the switch bank connects A and B ports when OE is low OR OE is high, and disconnects only when OE is high AND OE is low. This dual-input structure allows flexible system-level control-e.g., OE driven by a processor GPIO (active-low) while OE is tied to V_CC (always high) for simplified single-signal operation.

Is the SN74CBT3345DW pin-compatible with the SN74LS245?

Yes, the SN74CBT3345DW uses the standard '245-type pinout defined in the datasheet, matching SN74LS245, SN74ACT245, and SN74LVC245A pin-for-pin in SOIC-20. However, unlike those tri-state buffers, SN74CBT3345DW is an analog switch-so while footprint and pin numbering align, functionality (bidirectional low-r_on pass-gate vs. directional 3-state driver) differs fundamentally.

SN74CBT3345DW Specifications

Product attributes: Attribute value

Manufacturer:: Texas Instruments

Series:: 74CBT

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

Packaging:: Bulk

Product Status:: Active

Type:: Bus Switch

Circuit:: 8 x 1:1

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:: 20-SOIC

SN74CBT3345DW FAQ

1.How can I place an order for SN74CBT3345DW through Aetrix?

Please submit a Request for Quotation (RFQ) for SN74CBT3345DW 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 SN74CBT3345DW reliable?

The price and inventory of SN74CBT3345DW are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74CBT3345DW is usually 5 days.

3.What payment methods are accepted for SN74CBT3345DW?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74CBT3345DW transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for SN74CBT3345DW?

SN74CBT3345DW orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your SN74CBT3345DW 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 SN74CBT3345DW?

For technical support, including SN74CBT3345DW datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74CBT3345DW requirements.

6.How does Aetrix verify that SN74CBT3345DW is sourced from the original manufacturer or authorized distributors?

All SN74CBT3345DW 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 SN74CBT3345DW meets industry standards.

7.What is the process for return or replacement of SN74CBT3345DW?

All SN74CBT3345DW units undergo pre-shipment inspection (PSI). If there is an issue with SN74CBT3345DW, 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 SN74CBT3345DW part is unused and in its original packaging.

Return procedure for SN74CBT3345DW:

1.Submit a request within 90 days.

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

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