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

Texas Instruments SN74CB3Q3305PW

Name: SN74CB3Q3305PW
Brand: Texas Instruments
SKU: SN74CB3Q3305PW
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: SN74CB3Q3305PW

Manufacturer:: Texas Instruments

Category:: Signal Switches, Multiplexers, Decoders

Package:: 8-TSSOP (0.173", 4.40mm Width)

Datasheet:: SN74CB3Q3305PW.pdf

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

Quantity:: RFQ Add To RFQ list

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Product details

Overview

SN74CB3Q3305PW from Texas Instruments is a dual 1-bit FET bus switch optimized for high-bandwidth, level-shifting signal routing in mixed-voltage systems. It supports bidirectional 0–5 V signal switching with 3.3 V V_CC, delivers 3 Ω typical ON-state resistance, <0.15 ns propagation delay, and 500 MHz bandwidth - enabling use in USB interfaces, optical networking backplanes, and broadband communications equipment.

For engineers reviewing the SN74CB3Q3305PW datasheet, SN74CB3Q3305PW pinout, SN74CB3Q3305PW application, or SN74CB3Q3305PW equivalent, key selection criteria include 5-V-tolerant I/Os under powered-up/down conditions, I_off-enabled partial-power-down isolation, low 3.5 pF OFF-state capacitance, and TSSOP-8 package compatibility with high-density PCB layouts.

Technical Context

The SN74CB3Q3305PW integrates two independent 1-bit switches, each controlled by dedicated OE inputs (1OE, 2OE), enabling flexible channel enable/disable sequencing. Its charge-pump-assisted gate drive maintains flat r_on (3–8 Ω) across 2.3–3.6 V V_CC and –40°C to 85°C, ensuring consistent signal integrity in voltage-translating paths.

Each switch supports true bidirectional operation with near-zero propagation delay (<0.15 ns), 5-V-tolerant I/Os regardless of V_CC state, and I_off protection that blocks current backflow during power-down - critical for hot-swap and partial-power-down system architectures.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CC Range	2.3 V to 3.6 V - enables interoperability with 2.5 V and 3.3 V logic domains while supporting 5 V signaling on I/Os
r_on (Typical)	3 Ω at V_CC = 3.3 V - minimizes voltage drop and distortion for high-speed digital signals up to 500 MHz
C_io(OFF)	3.5 pF typical - reduces capacitive loading on buses, preserving signal rise/fall times and impedance matching
Propagation Delay	0.15 ns max at 3.3 V - supports sub-nanosecond timing budgets in DDR, PCIe, and USB 2.0 signal paths
I/O Voltage Range	0 V to 5.5 V - allows seamless interfacing between 1.8 V/2.5 V/3.3 V controllers and 5 V peripherals without external level shifters
f_OE Max	20 MHz - permits rapid channel enable/disable cycling for dynamic bus arbitration and power gating
I_off	1 µA at V_CC = 0 V - ensures robust isolation and prevents leakage-induced latch-up during partial power-down

Pinout & Package

TSSOP-8 (PW) package: 3.00 mm × 6.10 mm body, 0.65 mm lead pitch, surface-mount, RoHS-compliant, moisture sensitivity level 1 (260°C peak reflow).

Pin/Terminal	Circuit Role	Design Meaning
1OE	Input	Active-high enable for Channel 1 (1A ↔ 1B); ties to GND via pulldown resistor for power-up high-impedance safety
1A, 1B	I/O	Bidirectional data ports for Channel 1; both tolerate 0–5.5 V regardless of V_CC state
GND	Power	Ground reference for internal charge pump and switch biasing; must be low-inductance connection
V_CC	Power	Supply input (2.3–3.6 V); requires local 0.1 µF ceramic bypass capacitor placed adjacent to pin
2OE	Input	Active-high enable for Channel 2 (2A ↔ 2B); independent control enables staggered channel activation
2A, 2B	I/O	Bidirectional data ports for Channel 2; identical electrical specs and overvoltage tolerance as Channel 1

Key Features

Feature	Design Value
5-V-tolerant I/Os with V_CC powered or unpowered	Enables safe hot-plug operation and mixed-voltage domain bridging without external clamping or translation circuitry
Charge-pump-enhanced gate drive	Maintains low, flat r_on across full V_CC and temperature range - eliminates signal attenuation variation in wide-temp applications
Independent dual-channel OE control	Allows per-channel power gating and dynamic bus segmentation - essential for low-power mode partitioning in networking SoCs
I_off protection	Prevents damaging back-current flow when V_CC is off, meeting JESD78 Class II latch-up immunity (>100 mA)
Low 3.5 pF OFF-state capacitance	Minimizes crosstalk and signal degradation in high-frequency parallel buses (e.g., address/data multiplexing in optical modules)

Applications

USB 2.0 Interface Isolation	Optical Module Data Path Switching
Use Scenario: Isolating USB host controller (3.3 V) from peripheral (5 V) during enumeration and suspend/resume cycles. IC Role / Device Role: Bidirectional level-translating bus switch enabling 480 Mbps data transfer without protocol-aware logic. Use Value: Eliminates need for discrete level shifters and reduces BOM count while maintaining signal integrity up to 500 MHz.	Use Scenario: Routing high-speed serial data between FPGA transceivers (2.5 V) and SFP+ optical PHYs (3.3 V/5 V). IC Role / Device Role: Low-capacitance, low-r_on signal path selector for EPON/GPON line cards requiring hot-swap capability. Use Value: Supports 5 V-tolerant signaling with <0.15 ns delay - preserves eye diagram margin in 1.25 Gbps/2.5 Gbps optical links.
WiMAX Baseband Signal Routing	IP Phone Audio/Data Bus Multiplexing
Use Scenario: Dynamically connecting baseband processors (1.8 V) to RF front-end ICs (3.3 V) in multi-standard wireless infrastructure. IC Role / Device Role: Dual-channel switch enabling time-division multiplexing of I/Q data paths with independent enable control. Use Value: Flat r_on ensures amplitude consistency across frequency bands; I_off prevents DC leakage during RF sleep modes.	Use Scenario: Sharing a single CODEC interface between VoIP processor (3.3 V) and analog handset (5 V) in enterprise IP phones. IC Role / Device Role: Level-shifting bus isolator for PCM audio and control signals, supporting simultaneous voice and data sessions. Use Value: 3.5 pF C_io(OFF) prevents audible artifacts; 5-V tolerance avoids external clamps on analog audio lines.

USB 2.0 Interface Isolation

Optical Module Data Path Switching

Use Scenario: Isolating USB host controller (3.3 V) from peripheral (5 V) during enumeration and suspend/resume cycles.

IC Role / Device Role: Bidirectional level-translating bus switch enabling 480 Mbps data transfer without protocol-aware logic.

Use Value: Eliminates need for discrete level shifters and reduces BOM count while maintaining signal integrity up to 500 MHz.

Use Scenario: Routing high-speed serial data between FPGA transceivers (2.5 V) and SFP+ optical PHYs (3.3 V/5 V).

IC Role / Device Role: Low-capacitance, low-r_on signal path selector for EPON/GPON line cards requiring hot-swap capability.

Use Value: Supports 5 V-tolerant signaling with <0.15 ns delay - preserves eye diagram margin in 1.25 Gbps/2.5 Gbps optical links.

WiMAX Baseband Signal Routing

IP Phone Audio/Data Bus Multiplexing

Use Scenario: Dynamically connecting baseband processors (1.8 V) to RF front-end ICs (3.3 V) in multi-standard wireless infrastructure.

IC Role / Device Role: Dual-channel switch enabling time-division multiplexing of I/Q data paths with independent enable control.

Use Value: Flat r_on ensures amplitude consistency across frequency bands; I_off prevents DC leakage during RF sleep modes.

Use Scenario: Sharing a single CODEC interface between VoIP processor (3.3 V) and analog handset (5 V) in enterprise IP phones.

IC Role / Device Role: Level-shifting bus isolator for PCM audio and control signals, supporting simultaneous voice and data sessions.

Use Value: 3.5 pF C_io(OFF) prevents audible artifacts; 5-V tolerance avoids external clamps on analog audio lines.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
SN74CBT3305CPW	Higher r_on (5 Ω typ), no charge pump, lower bandwidth (300 MHz), same TSSOP-8 footprint	Lacks 5-V tolerance during power-down; unsuitable for hot-swap or partial-power-down systems	Select only if cost sensitivity outweighs I_off and bandwidth requirements
TS3A24159DGSR	Lower r_on (0.7 Ω), 3.6 V max V_CC, 3.6 V max I/O, no I_off, 10-pin VSSOP	Not 5-V tolerant; requires external protection diodes for >3.6 V signals; incompatible pinout	Use only for strictly 3.3 V-only systems where ultra-low r_on is prioritized over voltage flexibility

Compared with SN74CB3Q3305PW, SN74CBT3305CPW offers lower cost but sacrifices I_off protection and bandwidth headroom, while TS3A24159DGSR provides superior r_on yet lacks the 5-V tolerance and power-down safety needed in mixed-voltage telecom infrastructure.

Availability

SN74CB3Q3305PW is available at Aetrix Electronics and suitable for optical networking, USB interface isolation, and WiMAX baseband routing requiring stable component supply across extended product lifecycles.

Supply support for SN74CB3Q3305PW 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 decades of expertise in high-speed interface solutions.

The SN74CB3Q3305PW belongs to TI's CB3Q family of charge-pump bus switches, engineered specifically for broadband communications, optical transport, and mixed-voltage system interconnects demanding 5-V tolerance and sub-nanosecond timing.

FAQ

What is the maximum signal frequency supported by the SN74CB3Q3305PW?

The SN74CB3Q3305PW supports up to 500 MHz signal bandwidth, verified under load conditions with typical r_on and C_io(OFF). This performance is enabled by its charge-pump architecture and low 3.5 pF OFF-state capacitance, making SN74CB3Q3305PW suitable for USB 2.0, EPON, and high-speed serial data routing where signal integrity is critical.

Does the SN74CB3Q3305PW support level shifting between 1.8 V and 5 V domains?

Yes - the SN74CB3Q3305PW supports bidirectional level shifting: with V_CC = 2.5 V, it switches 0–3.3 V signals; with V_CC = 3.3 V, it handles 0–5 V signals. Its 5-V-tolerant I/Os operate safely whether V_CC is powered or fully off, making SN74CB3Q3305PW ideal for mixed-voltage system interconnects without external translators.

How does the I_off feature protect the SN74CB3Q3305PW during partial power-down?

The I_off circuitry in the SN74CB3Q3305PW actively blocks current backflow through the switch when V_CC = 0 V, limiting leakage to 1 µA. This prevents damage to upstream/downstream components and meets JESD78 Class II latch-up immunity (>100 mA), ensuring SN74CB3Q3305PW remains safe and functional in hot-swap or power-gated subsystems.

Can the SN74CB3Q3305PW be used with 2.5 V V_CC while passing 5 V signals?

No - with 2.5 V V_CC, the SN74CB3Q3305PW supports only 0–3.3 V I/O signaling, as specified in the datasheet. For 5 V signal pass-through, V_CC must be ≥3.0 V (recommended 3.3 V). This limitation is inherent to the charge-pump design and is explicitly defined in SN74CB3Q3305PW's recommended operating conditions.

What is the recommended bypass capacitor for the SN74CB3Q3305PW V_CC pin?

A 0.1 µF ceramic capacitor is required directly adjacent to the V_CC pin of the SN74CB3Q3305PW, as specified in Section 10 of the datasheet. This capacitor stabilizes the internal charge pump and suppresses high-frequency noise; placement within 2 mm of the pin is critical to maintain SN74CB3Q3305PW's 500 MHz performance and low-noise switching behavior.

SN74CB3Q3305PW Specifications

Product attributes: Attribute value

Manufacturer:: Texas Instruments

Series:: 74CB

Package/Case:: 8-TSSOP (0.173", 4.40mm Width)

Packaging:: Bulk

Product Status:: Obsolete

Type:: Bus Switch

Circuit:: 1 x 1:1

Independent Circuits:: 2

Current - Output High, Low:: -

Voltage Supply Source:: Single Supply

Voltage - Supply:: 2.3V ~ 3.6V

Operating Temperature:: -40°C ~ 85°C

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 8-TSSOP

SN74CB3Q3305PW FAQ

1.How can I place an order for SN74CB3Q3305PW through Aetrix?

Please submit a Request for Quotation (RFQ) for SN74CB3Q3305PW 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 SN74CB3Q3305PW reliable?

The price and inventory of SN74CB3Q3305PW are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74CB3Q3305PW is usually 5 days.

3.What payment methods are accepted for SN74CB3Q3305PW?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74CB3Q3305PW transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for SN74CB3Q3305PW?

SN74CB3Q3305PW orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your SN74CB3Q3305PW 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 SN74CB3Q3305PW?

For technical support, including SN74CB3Q3305PW datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74CB3Q3305PW requirements.

6.How does Aetrix verify that SN74CB3Q3305PW is sourced from the original manufacturer or authorized distributors?

All SN74CB3Q3305PW 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 SN74CB3Q3305PW meets industry standards.

7.What is the process for return or replacement of SN74CB3Q3305PW?

All SN74CB3Q3305PW units undergo pre-shipment inspection (PSI). If there is an issue with SN74CB3Q3305PW, 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 SN74CB3Q3305PW part is unused and in its original packaging.

Return procedure for SN74CB3Q3305PW:

1.Submit a request within 90 days.

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

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