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

Texas Instruments SN74CBT3345DBLE

Name: SN74CBT3345DBLE
Brand: Texas Instruments
SKU: SN74CBT3345DBLE
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: SN74CBT3345DBLE

Manufacturer:: Texas Instruments

Category:: Signal Switches, Multiplexers, Decoders

Package:: -

Datasheet:: SN74CBT3345DBLE.pdf

Description:: BUS DRIVER

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Product details

Overview

SN74CBT3345DBLE from Texas Instruments is an 8-bit high-speed TTL-compatible bus switch IC with dual output-enable control, 5-Ω on-state resistance, 0.25 ns propagation delay, and standard '245 pinout. It enables bidirectional signal routing between two ports (A and B) in memory expansion, data multiplexing, and hot-swap interface applications.

For engineers reviewing the SN74CBT3345DBLE datasheet, SN74CBT3345DBLE pinout, SN74CBT3345DBLE application, or SN74CBT3345DBLE equivalent, key selection criteria include its dual-OE logic control scheme, low on-resistance switching, TTL-level compatibility, and operation across −40°C to 85°C with 4.5 V–5.5 V supply.

Technical Context

The SN74CBT3345DBLE implements a single 8-bit switch bank with complementary OE and OE inputs: the switch conducts when OE is low OR OE is high, and disconnects only when OE is high AND OE is low. Its architecture uses NMOS pass transistors without level-shifting circuitry, preserving signal integrity for DC-coupled TTL/CMOS buses.

It operates strictly as a passive analog switch - no internal latching, buffering, or voltage translation - with rail-to-rail signal handling (−0.5 V to 7 V), 6 pF off-state capacitance, and ±1 µA input leakage. The device requires external pull-up/down on unused control inputs per TI SCBA004 guidance to prevent floating-node-induced current draw.

Key Specifications

Parameter	Value and Actual Design Meaning
On-state resistance (ron)	5 Ω typical at VCC = 4.5 V, enabling minimal voltage drop (<150 mV at 30 mA) and low insertion loss in signal paths.
Propagation delay (tpd)	0.25 ns typical at CL = 50 pF, supporting >1 GHz signal bandwidth for high-speed digital interconnects.
Supply voltage range	4.5 V to 5.5 V - compatible with standard 5-V TTL systems; absolute max rating extends to 7 V for transient tolerance.
Input voltage range (VI)	−0.5 V to 7 V - supports fault-tolerant operation and mixed-voltage domain interfacing without clamping diodes.
Off-state capacitance (Cio)	6 pF - minimizes capacitive loading and crosstalk during isolation, critical for high-frequency bus partitioning.
Operating temperature	−40°C to +85°C - qualified for industrial-grade embedded systems and communications equipment.
Control input thresholds	VIL ≤ 0.8 V, VIH ≥ 2.0 V - fully compatible with standard TTL logic families without level-shifting.

Pinout & Package

SN74CBT3345DBLE is packaged in a 20-pin SSOP (Shrink Small Outline Package), body dimension 7.2 mm × 5.3 mm, 0.65 mm lead pitch, 1.2 mm max height. Pin 1 marked via corner chamfer or index area.

Pin/Terminal	Circuit Role	Design Meaning
1, 19	OE / OE	Complementary output-enable inputs: switch ON when OE = L or OE = H; OFF only when OE = H AND OE = L.
2–9	A1–A8	Port A bidirectional I/O terminals - connect to source bus (e.g., microcontroller data lines).
11–18	B1–B8	Port B bidirectional I/O terminals - connect to destination bus (e.g., peripheral or memory interface).
10	GND	Ground reference for all internal circuitry and signal return path.
20	VCC	Positive supply (4.5–5.5 V); powers internal switch transistors and input buffers.

Key Features

Feature	Design Value
Standard '245 pinout	Enables drop-in replacement of legacy 74-series bus transceivers without PCB redesign.
Dual active-low/high enable logic	Supports flexible system-level control - e.g., one enable tied to processor GPIO, the other to power-good signal.
5-Ω low on-resistance	Reduces resistive attenuation and timing skew across all 8 channels, preserving signal rise/fall times.
TTL-compatible inputs	Eliminates need for external level shifters when interfacing with 5-V microcontrollers, FPGAs, or ASICs.
High off-isolation (6 pF Cio)	Prevents signal bleed-through during disable state, essential for bus arbitration and hot-plug isolation.

Applications

Memory Expansion Interface	Data Multiplexing
Use Scenario: Expanding address/data bus width between a microcontroller and multiple SRAM or Flash devices using shared bus segments. IC Role / Device Role / Timing Role: Bidirectional 8-bit bus switch isolating memory banks during access, controlled by chip-select logic mapped to OE/OE. Use Value: Enables time-multiplexed memory access without bus contention, leveraging sub-nanosecond propagation delay to maintain system timing margins.	Use Scenario: Routing sensor data from multiple analog front-ends to a single ADC input channel under microcontroller control. IC Role / Device Role / Timing Role: Analog/digital signal selector providing low-distortion, rail-to-rail signal pass-through with no added latency. Use Value: 5-Ω ron ensures <0.1% gain error at 10 mA load; 6 pF Cio prevents channel-to-channel crosstalk below −40 dB at 10 MHz.
Hot-Swap I/O Isolation	Legacy Bus Bridging
Use Scenario: Safely inserting/removing peripheral modules in powered-backplane systems while maintaining host bus integrity. IC Role / Device Role / Timing Role: Signal gate that electrically isolates hot-swap connectors from main system bus until power and reset sequencing completes. Use Value: −0.5 V to 7 V input tolerance accommodates backplane transients; high-impedance off-state prevents back-driving during insertion.	Use Scenario: Interfacing modern 5-V FPGA I/O banks with legacy 5-V TTL peripherals requiring strict '245-style timing and drive strength. IC Role / Device Role / Timing Role: Pin-compatible bus switch replacing obsolete 74ACT245 or 74LS245 with superior speed and lower power. Use Value: 0.25 ns tpd improves setup/hold margin by >150 ps vs. 74LS245 (typ. 12 ns), enabling higher clock rates in bridged interfaces.

Memory Expansion Interface

Data Multiplexing

Use Scenario: Expanding address/data bus width between a microcontroller and multiple SRAM or Flash devices using shared bus segments.

IC Role / Device Role / Timing Role: Bidirectional 8-bit bus switch isolating memory banks during access, controlled by chip-select logic mapped to OE/OE.

Use Value: Enables time-multiplexed memory access without bus contention, leveraging sub-nanosecond propagation delay to maintain system timing margins.

Use Scenario: Routing sensor data from multiple analog front-ends to a single ADC input channel under microcontroller control.

IC Role / Device Role / Timing Role: Analog/digital signal selector providing low-distortion, rail-to-rail signal pass-through with no added latency.

Use Value: 5-Ω ron ensures <0.1% gain error at 10 mA load; 6 pF Cio prevents channel-to-channel crosstalk below −40 dB at 10 MHz.

Hot-Swap I/O Isolation

Legacy Bus Bridging

Use Scenario: Safely inserting/removing peripheral modules in powered-backplane systems while maintaining host bus integrity.

IC Role / Device Role / Timing Role: Signal gate that electrically isolates hot-swap connectors from main system bus until power and reset sequencing completes.

Use Value: −0.5 V to 7 V input tolerance accommodates backplane transients; high-impedance off-state prevents back-driving during insertion.

Use Scenario: Interfacing modern 5-V FPGA I/O banks with legacy 5-V TTL peripherals requiring strict '245-style timing and drive strength.

IC Role / Device Role / Timing Role: Pin-compatible bus switch replacing obsolete 74ACT245 or 74LS245 with superior speed and lower power.

Use Value: 0.25 ns tpd improves setup/hold margin by >150 ps vs. 74LS245 (typ. 12 ns), enabling higher clock rates in bridged interfaces.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
SN74CBTD3305PWR	10-bit configuration, 3-state outputs, 3.3-V only (VCC = 2.3–3.6 V), higher ron (~7 Ω), no dual-OE logic.	Designed for 3.3-V LVTTL/LVCMOS systems; lacks 5-V tolerance and '245 pinout compatibility.	Select when operating exclusively at 3.3 V and requiring 10-bit width; not suitable for 5-V TTL replacement.
SN74LVC245APW	True transceiver (direction-controlled), 8-bit, 1.65–3.6 V supply, 3-state outputs, no analog switch behavior.	Provides direction control (DIR pin) and output enable (OE), but cannot pass signals bidirectionally without direction management.	Choose for bidirectional data flow with explicit direction control; avoid when transparent analog switching is required.

Compared with SN74CBT3345DBLE, SN74CBTD3305PWR offers wider bit count but sacrifices 5-V operation and pinout compatibility, while SN74LVC245APW adds direction control at the cost of analog transparency and TTL-level robustness - making SN74CBT3345DBLE uniquely suited for low-latency, 5-V, '245-form-factor bus gating.

Availability

SN74CBT3345DBLE is available at Aetrix Electronics and suitable for memory expansion, hot-swap I/O isolation, and legacy bus bridging requiring stable component supply, industrial temperature support, and long-term obsolescence mitigation.

Supply support for SN74CBT3345DBLE 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 SN74CBT3345DBLE belongs to TI's CBT (Crossbar Bus Transceiver) family, engineered specifically for high-speed, low-distortion analog switching in 5-V TTL-based digital systems where minimal propagation delay and pinout compatibility are critical.

FAQ

What is the function of the dual OE inputs on the SN74CBT3345DBLE?

The SN74CBT3345DBLE features complementary OE and OE inputs to provide flexible enable logic: the internal 8-bit switch conducts (A↔B connected) when OE is low OR OE is high, and enters high-impedance isolation only when OE is high AND OE is low. This dual-input scheme allows system designers to implement redundant enable conditions, power-gated control, or inverted logic paths without external gates - a key differentiator from single-OE bus switches.

Can the SN74CBT3345DBLE operate with a 3.3-V supply?

No, the SN74CBT3345DBLE is specified only for 4.5 V to 5.5 V operation per its recommended conditions; it is not rated for 3.3-V use. Attempting 3.3-V supply may result in undefined switching behavior, excessive on-resistance (>20 Ω), or failure to meet VIH/VIL thresholds. For 3.3-V systems, TI recommends the SN74CBTD3305PWR or SN74LVC245A instead - neither of which is a direct replacement for SN74CBT3345DBLE.

Does the SN74CBT3345DBLE support hot-swap applications?

Yes, the SN74CBT3345DBLE supports hot-swap applications due to its −0.5 V to 7 V input voltage rating, which tolerates backplane transients and undershoot during insertion, and its high-impedance off-state that prevents back-driving of live buses. When OE and OE are held inactive (OE = H, OE = L), the A–B path presents >10⁹ Ω isolation and only 6 pF capacitance - verified in TI's SCDS027I datasheet under "electrical characteristics" and "absolute maximum ratings".

Is the SN74CBT3345DBLE pin-compatible with standard 74-series '245 devices?

Yes, the SN74CBT3345DBLE uses the industry-standard '245-type pinout: pins 2–9 = A1–A8, pins 11–18 = B1–B8, pin 1 = OE, pin 19 = OE, pin 10 = GND, and pin 20 = VCC. This allows direct PCB substitution for legacy 74ACT245, 74LS245, or 74F245 in existing layouts - provided supply and logic levels match the SN74CBT3345DBLE's 4.5–5.5 V and TTL-compatible thresholds.

What is the maximum continuous current per channel for the SN74CBT3345DBLE?

The SN74CBT3345DBLE supports up to 128 mA continuous channel current per A–B path, as specified in the "absolute maximum ratings" table of the SCDS027I datasheet. However, for reliable operation within recommended conditions, TI specifies 30 mA test current for on-resistance measurement and limits total ICC to 50 µA quiescent draw - meaning sustained 128 mA operation requires careful thermal design and is typically reserved for short-duration pulses, not DC loads.

SN74CBT3345DBLE 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:: -

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Qualification:: -

Mounting Type:: -

Supplier Device Package:: -

SN74CBT3345DBLE FAQ

1.How can I place an order for SN74CBT3345DBLE through Aetrix?

Please submit a Request for Quotation (RFQ) for SN74CBT3345DBLE 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 SN74CBT3345DBLE reliable?

The price and inventory of SN74CBT3345DBLE are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74CBT3345DBLE is usually 5 days.

3.What payment methods are accepted for SN74CBT3345DBLE?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74CBT3345DBLE transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for SN74CBT3345DBLE?

SN74CBT3345DBLE orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your SN74CBT3345DBLE 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 SN74CBT3345DBLE?

For technical support, including SN74CBT3345DBLE datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74CBT3345DBLE requirements.

6.How does Aetrix verify that SN74CBT3345DBLE is sourced from the original manufacturer or authorized distributors?

All SN74CBT3345DBLE 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 SN74CBT3345DBLE meets industry standards.

7.What is the process for return or replacement of SN74CBT3345DBLE?

All SN74CBT3345DBLE units undergo pre-shipment inspection (PSI). If there is an issue with SN74CBT3345DBLE, 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 SN74CBT3345DBLE part is unused and in its original packaging.

Return procedure for SN74CBT3345DBLE:

1.Submit a request within 90 days.

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

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