Texas Instruments SN74CB3Q3305PWRE4

Overview

SN74CB3Q3305 from Texas Instruments is a dual 1-bit FET bus switch optimized for high-bandwidth, bidirectional signal routing in mixed-voltage systems. It features 3 Ω typical ON-state resistance, 5-V tolerant I/Os with 2.3–3.6 V VCC operation, and supports 0–5 V signal switching at 3.3 V supply - enabling level translation between 5 V controllers and 3.3 V peripherals in optical networking and USB interfaces.

For engineers reviewing the SN74CB3Q3305 datasheet, SN74CB3Q3305 pinout, SN74CB3Q3305 application, or SN74CB3Q3305 equivalent, key selection criteria include its 500 MHz bandwidth capability, Ioff partial-power-down protection, near-zero propagation delay (0.15 ns), low 3.5 pF OFF-state capacitance, and dual independent OE control for isolated channel management.

Technical Context

The SN74CB3Q3305 implements two independent, charge-pump-assisted FET switches to maintain flat, low ron across voltage and temperature - enabling stable impedance matching for broadband signals up to 500 MHz. Each switch operates bidirectionally with separate 1OE/2OE enables, supporting independent channel isolation without directionality constraints.

Its architecture integrates undershoot clamp diodes on all data and control pins, 5-V tolerance during power-up/down via Ioff circuitry, and TTL/CMOS-compatible control inputs. The device achieves 20 MHz maximum OE toggle frequency while maintaining sub-5 pF OFF-state I/O capacitance to minimize signal distortion in high-speed serial links.

Key Specifications

Pinout & Package

SN74CB3Q3305 is packaged in an 8-pin TSSOP (PW) with 3.00 mm × 6.10 mm body size, RoHS-compliant NIPDAU lead finish, and MSL Level-1 rating for standard reflow compatibility.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74CB3Q3305, SN74CBT3305PWR trades bandwidth and ron performance for cost reduction in non-critical timing applications, while TS3A24159RGTR offers lower ron and smaller footprint at the expense of 5-V I/O compatibility - making SN74CB3Q3305 the only option supporting 500 MHz operation with full 5-V tolerance and dual independent enables.

Availability

SN74CB3Q3305 is available at Aetrix Electronics and suitable for optical networking, USB 2.0 interface isolation, and PBX backplane signal routing requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant TSSOP packaging.

Supply support for SN74CB3Q3305 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 precision analog design and high-reliability manufacturing.

The SN74CB3Q3305 belongs to TI's CB3Q family of high-bandwidth FET bus switches, engineered specifically for broadband communications infrastructure where signal fidelity, voltage flexibility, and power-aware isolation are critical.

FAQ

What is the maximum operating frequency supported by the SN74CB3Q3305?

The SN74CB3Q3305 supports a maximum data path bandwidth of 500 MHz, verified under recommended operating conditions (VCC = 3.3 V, TA = 25°C). This specification reflects its capability to handle high-speed serial protocols like USB 2.0 and EPON baseband signals without significant attenuation or phase distortion. The actual usable frequency depends on PCB layout, trace impedance, and load capacitance.

Does the SN74CB3Q3305 support level translation between 5 V and 3.3 V systems?

Yes, the SN74CB3Q3305 supports bidirectional level translation: it accepts 0–5 V signals on its I/O ports while operating from a 3.3 V (or 2.5 V) VCC supply. This is enabled by its 5-V tolerant I/O structure and internal charge pump, allowing seamless interfacing between 5 V microcontrollers and 3.3 V peripherals without external level shifters - a core function of the SN74CB3Q3305.

How does the Ioff feature protect the SN74CB3Q3305 during partial power-down?

The Ioff circuitry in the SN74CB3Q3305 limits current backflow to ≤1 µA when VCC = 0 V, even if 0–5.5 V signals remain present on I/O pins. This prevents damaging latch-up or excessive power dissipation during hot-swap events or staged system power sequencing - a critical reliability feature confirmed in the SN74CB3Q3305 datasheet's absolute maximum ratings and functional modes section.

Can both channels of the SN74CB3Q3305 be controlled independently?

Yes, the SN74CB3Q3305 provides two independent output-enable inputs: 1OE controls Channel 1 (1A ↔ 1B), and 2OE controls Channel 2 (2A ↔ 2B). Each enable operates asynchronously, allowing one channel to pass signals while the other remains in high-impedance state - essential for dynamic bus arbitration and multi-lane isolation in systems using the SN74CB3Q3305.

What package options are available for the SN74CB3Q3305, and which one is used in SN74CB3Q3305PWRE4?

The SN74CB3Q3305PWRE4 uses the 8-pin TSSOP (PW) package, measuring 3.00 mm × 6.10 mm, with NIPDAU lead finish and MSL Level-1 rating. Other variants include VSSOP (DCU) packaging, but SN74CB3Q3305PWRE4 is exclusively offered in TSSOP - confirmed in TI's official packaging addendum and orderable part number documentation for the SN74CB3Q3305.