Send an Inquiry

To receive a quote for your project, please fill in the following information, and we’ll get back to you promptly.

Submit Inventory List

Please fill in the following information, and we’ll get back to you promptly.

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

Texas Instruments SN74CBT3245APWR

Name: SN74CBT3245APWR
Brand: Texas Instruments
SKU: SN74CBT3245APWR
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

Compare

Part No.:: SN74CBT3245APWR

Manufacturer:: Texas Instruments

Category:: Signal Switches, Multiplexers, Decoders

Package:: 20-TSSOP (0.173", 4.40mm Width)

Datasheet:: SN74CBT3245APWR.pdf

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

Quantity:: RFQ Add To RFQ list

Payment:

Shipping:

Inventory:704

Please send an inquiry. Send us your inquiry, and we will respond immediately.

Product details

Overview

SN74CBT3245APWR from Texas Instruments is an octal FET bus switch IC designed for high-speed TTL-compatible bidirectional signal routing between two 8-bit ports (A and B). It features 5-Ω on-state resistance, 0.25 ns typical propagation delay at 5 V, and operates from −40°C to 85°C with supply voltage 4–5.5 V. It is used in data path isolation, memory address multiplexing, and hot-swap I/O buffering.

For engineers reviewing the SN74CBT3245APWR datasheet, SN74CBT3245APWR pinout, SN74CBT3245APWR application, or SN74CBT3245APWR equivalent, key selection criteria include on-resistance matching, OE-controlled bidirectional switching, TTL-level compatibility, thermal performance in TSSOP-20, and high-impedance state behavior during power sequencing.

Technical Context

The SN74CBT3245APWR implements eight independent FET-based analog switches in a single 20-pin TSSOP package, each connecting corresponding A_n and B_n terminals. Its operation is controlled solely by a single active-low output-enable (OE) input: low enables bidirectional conduction; high places both ports in high-impedance isolation.

It uses no internal level-shifting circuitry-signal integrity relies on maintaining V_CC within 4–5.5 V and ensuring OE is pulled up to V_CC during power-up/down to guarantee default high-Z state. Input clamp current is rated ±50 mA, supporting robust ESD transient handling without external protection diodes.

Key Specifications

Parameter	Value and Actual Design Meaning
On-state resistance (r_on)	5 Ω typical at V_CC = 4.5 V - ensures minimal voltage drop and signal attenuation for 3.3 V/5 V logic signals.
Propagation delay (t_pd)	0.25 ns typical at V_CC = 5 V - enables use in >1 GHz data paths with negligible timing skew across all 8 channels.
Supply voltage range	4 V to 5.5 V - compatible with standard 5 V TTL and mixed-voltage 3.3 V/5 V system interfaces.
Input voltage range (VI)	−0.5 V to 7 V - supports overvoltage tolerance beyond V_CC, critical for hot-plug and bus contention scenarios.
Channel current rating	128 mA continuous - sufficient for driving 50 pF loads at full speed without derating.
Thermal impedance (θ_JA)	83 °C/W for PW package - defines maximum power dissipation (≈150 mW at ΔT = 12.5°C) under natural convection.
Operating temperature	−40°C to +85°C - qualified for industrial-grade embedded control and communications equipment.

Pinout & Package

TSSOP-20 (PW) package: 6.5 mm × 4.4 mm body, 0.65 mm lead pitch, 1.2 mm max height, exposed pad not present, RoHS-compliant NiPdAu lead finish, MSL Level-1.

Pin/Terminal	Circuit Role	Design Meaning
1, 2, 3, 4, 5, 6, 7, 8	A1–A8	Port A input/output terminals - bidirectionally connected to B1–B8 when OE is low.
9	GND	Ground reference for all internal FETs and logic - must be low-impedance for stable r_on and noise immunity.
10	V_CC	Positive supply for switch FETs and OE input buffer - decoupling capacitor required within 1 cm.
11	OE	Active-low output enable - must be tied to V_CC via pullup resistor during power transitions to prevent undefined state.
12, 13, 14, 15, 16, 17, 18, 19	B1–B8	Port B input/output terminals - electrically identical to A1–A8; no directionality imposed by device.
20	NC	No internal connection - left unconnected; not usable as heat slug or ground tie.

Key Features

Feature	Design Value
Standard '245-type pinout	Enables drop-in replacement of legacy 74LS245/74ACT245 in existing PCB layouts without redesign.
TTL-compatible input levels	VIH = 2 V min / VIL = 0.8 V max allows direct interfacing with 5 V TTL, LVTTL, and mixed-signal microcontrollers.
Low on-state capacitance	C_io(OFF) = 4 pF ensures minimal loading on adjacent traces and preserves signal edge rates in high-speed buses.
High-impedance fail-safe on power cycle	OE tied to V_CC forces open-switch state at power-up/down - prevents bus contention in sequenced power systems.
Minimal propagation delay variation	Δt_pd < 0.1 ns across all 8 channels - maintains inter-channel skew below 100 ps for parallel data buses.

Applications

Memory Address Multiplexing	PCI/ISA Bus Isolation
Use Scenario: Isolating address lines between CPU and multiple memory banks to prevent contention during bank switching. IC Role / Device Role / Timing Role: Bidirectional analog switch enabling dynamic reconfiguration of 8-bit address paths with sub-nanosecond latency. Use Value: Eliminates need for discrete logic gates or complex CPLD-based address decoding, reducing BOM count and layout area.	Use Scenario: Segregating legacy PCI or ISA peripheral slots from main system bus to support hot-plug insertion/removal. IC Role / Device Role / Timing Role: OE-controlled bus barrier that blocks signal coupling until slot power and reset are stable. Use Value: Prevents spurious writes and bus lockups during card insertion, meeting PCI hot-plug electrical compliance requirements.
Microcontroller I/O Expansion	Digital Test Equipment Signal Routing
Use Scenario: Extending GPIO count of an MCU by time-multiplexing shared data lines across multiple peripherals (e.g., ADC, DAC, EEPROM). IC Role / Device Role / Timing Role: Low-r_on switch enabling transparent read/write access to external devices without level-shifter overhead. Use Value: Maintains full 5 V logic swing integrity and supports >10 MHz data rates-exceeding typical SPI/I²C speeds.	Use Scenario: Configurable signal path selection in automated test equipment (ATE) for routing DUT signals to measurement instruments. IC Role / Device Role / Timing Role: Precision analog switch providing repeatable 5 Ω path resistance and <100 ps channel-to-channel skew. Use Value: Enables calibrated signal injection and measurement without introducing gain error or phase distortion in DC–100 MHz range.

Memory Address Multiplexing

PCI/ISA Bus Isolation

Use Scenario: Isolating address lines between CPU and multiple memory banks to prevent contention during bank switching.

IC Role / Device Role / Timing Role: Bidirectional analog switch enabling dynamic reconfiguration of 8-bit address paths with sub-nanosecond latency.

Use Value: Eliminates need for discrete logic gates or complex CPLD-based address decoding, reducing BOM count and layout area.

Use Scenario: Segregating legacy PCI or ISA peripheral slots from main system bus to support hot-plug insertion/removal.

IC Role / Device Role / Timing Role: OE-controlled bus barrier that blocks signal coupling until slot power and reset are stable.

Use Value: Prevents spurious writes and bus lockups during card insertion, meeting PCI hot-plug electrical compliance requirements.

Microcontroller I/O Expansion

Digital Test Equipment Signal Routing

Use Scenario: Extending GPIO count of an MCU by time-multiplexing shared data lines across multiple peripherals (e.g., ADC, DAC, EEPROM).

IC Role / Device Role / Timing Role: Low-r_on switch enabling transparent read/write access to external devices without level-shifter overhead.

Use Value: Maintains full 5 V logic swing integrity and supports >10 MHz data rates-exceeding typical SPI/I²C speeds.

Use Scenario: Configurable signal path selection in automated test equipment (ATE) for routing DUT signals to measurement instruments.

IC Role / Device Role / Timing Role: Precision analog switch providing repeatable 5 Ω path resistance and <100 ps channel-to-channel skew.

Use Value: Enables calibrated signal injection and measurement without introducing gain error or phase distortion in DC–100 MHz range.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
SN74CBTD3384APWR	Includes integrated 5-V tolerant level shifters; higher r_on (7 Ω); requires dual supplies (V_CCA/V_CCB).	Suitable for mixed-voltage systems (e.g., 3.3 V MCU ↔ 5 V peripheral), not pure 5 V buses.	Choose only if level translation between non-matching logic families is required; otherwise SN74CBT3245APWR offers lower r_on and simpler biasing.
74LVC245APW	True 3.3 V CMOS transceiver with direction control (DIR); not bidirectional analog switch; higher propagation delay (3.4 ns).	Used where unidirectional data flow and voltage translation (1.65–3.3 V) are needed-not for analog signal pass-through.	Select when directionality and 3.3 V compatibility are mandatory; avoid when sub-ns timing or true bidirectional analog switching is required.

Compared with SN74CBTD3384APWR and 74LVC245APW, the SN74CBT3245APWR delivers the lowest on-resistance and fastest propagation in a single-supply 5 V environment, making it optimal for high-fidelity, low-latency bus gating where voltage translation is unnecessary.

Availability

SN74CBT3245APWR is available at Aetrix Electronics and suitable for industrial control backplanes, legacy bus interface modules, and embedded test instrumentation requiring stable component supply and long-term obsolescence management.

Supply support for SN74CBT3245APWR 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 50 years of innovation in logic and interface solutions.

The SN74CBT3245APWR belongs to the CBT (Crossbar Bus Transceiver) family, engineered for ultra-low-latency, high-fidelity digital signal routing in legacy and mixed-voltage computing infrastructure.

FAQ

What is the maximum continuous current per channel for the SN74CBT3245APWR?

The SN74CBT3245APWR supports 128 mA continuous channel current per switch. This rating applies under recommended operating conditions (V_CC = 4–5.5 V, T_A = −40°C to 85°C) and ensures reliable conduction without thermal runaway or r_on drift. Exceeding this current may degrade on-resistance stability or accelerate electromigration in the internal FET channel.

Can the SN74CBT3245APWR operate with a 3.3 V supply?

No-the SN74CBT3245APWR is not specified for 3.3 V operation. Its recommended V_CC range is 4 V to 5.5 V, and its TTL-compatible inputs require VIH ≥ 2 V and VIL ≤ 0.8 V relative to V_CC. At 3.3 V, input thresholds become marginal and on-resistance increases significantly, risking timing violations and increased power dissipation. Use SN74LVC245A for 3.3 V systems.

Is the SN74CBT3245APWR pin-compatible with older 74-series bus transceivers like the 74LS245?

Yes-the SN74CBT3245APWR uses the standard '245-type pinout (A1–A8, GND, V_CC, OE, B1–B8, NC) in TSSOP-20, matching the physical pin assignments of 74LS245, 74ACT245, and 74F245 in SOIC-20. However, it lacks direction control (DIR) and operates as a bidirectional analog switch rather than a digital transceiver, so system-level logic must accommodate OE-only control.

Does the SN74CBT3245APWR require external pull-up resistors on the OE pin?

Yes-to ensure high-impedance state during power-up and power-down, OE must be tied to V_CC through an external pull-up resistor. The minimum value depends on the driver's sink capability; TI recommends ≥10 kΩ for typical microcontroller GPIO outputs. Without this, OE may float, causing unpredictable switching or bus contention during supply ramp.

What is the thermal performance of the SN74CBT3245APWR in its TSSOP-20 (PW) package?

The SN74CBT3245APWR in TSSOP-20 has a junction-to-ambient thermal resistance (θ_JA) of 83 °C/W under standard JEDEC test conditions. At maximum continuous power dissipation (~150 mW), this yields ~12.5°C junction-to-ambient rise above ambient temperature-well within safe operating limits for industrial environments. No heatsink is required for typical bus-switching duty cycles.

SN74CBT3245APWR Specifications

Product attributes: Attribute value

Manufacturer:: Texas Instruments

Series:: 74CBT

Package/Case:: 20-TSSOP (0.173", 4.40mm 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-TSSOP

SN74CBT3245APWR FAQ

1.How can I place an order for SN74CBT3245APWR through Aetrix?

Please submit a Request for Quotation (RFQ) for SN74CBT3245APWR 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 SN74CBT3245APWR reliable?

The price and inventory of SN74CBT3245APWR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74CBT3245APWR is usually 5 days.

3.What payment methods are accepted for SN74CBT3245APWR?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74CBT3245APWR transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for SN74CBT3245APWR?

SN74CBT3245APWR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your SN74CBT3245APWR 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 SN74CBT3245APWR?

For technical support, including SN74CBT3245APWR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74CBT3245APWR requirements.

6.How does Aetrix verify that SN74CBT3245APWR is sourced from the original manufacturer or authorized distributors?

All SN74CBT3245APWR 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 SN74CBT3245APWR meets industry standards.

7.What is the process for return or replacement of SN74CBT3245APWR?

All SN74CBT3245APWR units undergo pre-shipment inspection (PSI). If there is an issue with SN74CBT3245APWR, 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 SN74CBT3245APWR part is unused and in its original packaging.

Return procedure for SN74CBT3245APWR:

1.Submit a request within 90 days.

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

Tech Hub

2026-09-03 Logic Level Shifter: How to Connect 3.3V and 5V Logic Safely

A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.

2026-09-03 74HC595 vs TPIC6B595: Output Drive, Pinout, Current, and Load Selection

The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…

2026-09-01 74HC595 Pinout, Timing, Output Current, and Applications

The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…

2026-09-01 Latch vs Flip-Flop: Timing, Differences and Design Choices

A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…

2026-08-30 D Latch Circuit: Truth Table, Timing, ICs and Applications

A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …

2026-08-28 SR Latch Explained: NOR and NAND Circuits, Truth Tables, and Applications

An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…

2026-08-27 Latch Circuit: SR and D Latches, Truth Tables, Timing, and Applications

Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…

2026-08-21 What Is an LED Driver? Types, Circuits, Dimming, and Selection

An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…

2026-08-18 Operational Amplifier (Op Amp): Basics, Configurations, Feedback and Applications

Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…

2026-08-14 Jumper Cables: How to Use, Connect and Choose Them Safely

Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…