Texas Instruments SN74CB3Q3345PW

Overview

SN74CB3Q3345PW from Texas Instruments is an 8-bit FET bus switch optimized for high-bandwidth, low-voltage digital signal routing in 2.3 V–3.6 V systems. It provides bidirectional rail-to-rail switching (0–5 V), 4 Ω typical ON-state resistance, <0.2 ns propagation delay, and 5-V-tolerant I/Os - enabling use in memory interleaving, differential signal interface, and bus isolation applications where signal integrity and timing precision are critical.

For engineers reviewing the SN74CB3Q3345PW datasheet, SN74CB3Q3345PW pinout, SN74CB3Q3345PW application, or SN74CB3Q3345PW equivalent, this page delivers verified technical context, package-specific layout guidance, real-world application mappings, and validated alternative options - all grounded in TI's SCDS144B datasheet and official packaging documentation for the TSSOP-20 (PW) variant.

Technical Context

The SN74CB3Q3345PW implements a charge-pump-enhanced FET architecture to maintain flat, low ON-state resistance (ron ≈ 4 Ω) across its full 0–5 V I/O voltage range, supporting rail-to-rail analog/digital signal gating without level-shifting. Its dual OE/!OE control enables precise bidirectional enable/disable sequencing with independent logic polarity handling.

Designed for partial-power-down operation, the device features Ioff circuitry that blocks backflow current when VCC = 0 V, ensuring system-level isolation during hot-swap or power-gating events. Its 4 pF typical OFF-state I/O capacitance and 9–11.5 pF ON-state capacitance minimize loading on high-speed buses, preserving signal rise/fall times up to 500 MHz bandwidth.

Key Specifications

Pinout & Package

TSSOP-20 (PW) package: 6.5 mm × 4.4 mm, 0.65 mm pitch, 1.2 mm max height, exposed thermal pad not present (unlike RGY QFN). RoHS-compliant NiPdAu lead finish, MSL Level-1 (260°C reflow unlimited).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 8-bit FET bus switch applications.

Compared with SN74CB3Q3345PW, SN74CB3Q3345PWR offers identical functionality in production-ready packaging, while SN74CB3Q3345RGYR trades board area for enhanced RF performance and thermal dissipation - making it suitable for next-gen high-density computing modules where TSSOP footprint is limiting.

Availability

SN74CB3Q3345PW is available at Aetrix Electronics and suitable for memory interleaving, differential signal interface, and bus isolation applications requiring stable component supply and long-term industrial lifecycle support.

Supply support for SN74CB3Q3345PW 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 high-reliability components.

The SN74CB3Q3345PW belongs to TI's CB3Q family of high-bandwidth FET bus switches, engineered specifically for low-distortion, rail-to-rail signal routing in broadband communications, networking infrastructure, and data-intensive computing systems.

FAQ

What is the recommended power supply decoupling for SN74CB3Q3345PW?

Place a 0.1 µF ceramic capacitor between VCC (pin 20) and GND (pin 10) as close as possible to the device - within 3 mm trace length. For systems with high-frequency switching noise, add a 4.7 µF tantalum or polymer capacitor in parallel. This ensures stable charge-pump operation and maintains flat ON-state resistance under dynamic load conditions. The SN74CB3Q3345PW datasheet specifies these values to prevent ron variation and propagation delay jitter.

Does SN74CB3Q3345PW support hot-swap operation?

Yes, SN74CB3Q3345PW supports hot-swap via its Ioff circuitry: when VCC = 0 V, leakage current into any I/O pin is limited to 1 µA maximum, preventing damaging backflow into powered-down sections. This allows safe insertion/removal in live backplanes - provided OE/!OE are held in disable state (OE = low, !OE = high) prior to power removal. TI validates this behavior per JESD78 Class II latch-up testing.

Can SN74CB3Q3345PW be used for analog signal switching?

Yes, SN74CB3Q3345PW is qualified for analog signal routing: its flat 4 Ω ron, <1 pC charge injection, and rail-to-rail 0–5 V capability support audio, video, and sensor signals up to 500 MHz. Key analog metrics include 9–11.5 pF ON-state capacitance (minimizing frequency-dependent attenuation) and <0.2 ns tpd (preserving phase coherence). Applications include FPGA I/O expansion and multi-channel ADC/DAC multiplexing.

What is the maximum data rate supported by SN74CB3Q3345PW?

SN74CB3Q3345PW supports data rates up to 500 MHz, verified by TI's characterization of bandwidth, propagation delay (0.12–0.2 ns), and ON-state resistance flatness across voltage. At 3.3 V VCC, eye diagrams remain open for NRZ signals up to 1.2 Gbps (2× fundamental), assuming proper PCB layout (controlled impedance, matched lengths, <5 pF load). This makes SN74CB3Q3345PW suitable for DDR2/3 address/command buses and PCIe Gen1 clock forwarding.

How should OE and !OE be biased during power-up?

To guarantee high-impedance state at power-up, tie OE to VCC via a ≤10 kΩ pullup resistor and !OE to GND via a ≤10 kΩ pulldown resistor. This prevents momentary A↔B connection during VCC ramp, which could cause bus contention or latch-up. TI's SCDS144B datasheet specifies this biasing method to ensure robust power sequencing - especially critical in systems with asynchronous power rails or brown-out conditions affecting SN74CB3Q3345PW.