Texas Instruments SN74CB3Q3253PW

Overview

SN74CB3Q3253PW from Texas Instruments is a dual 1-of-4 FET multiplexer–demultiplexer bus switch optimized for high-bandwidth digital signal routing. It operates from 2.3 V to 3.6 V, delivers 4 Ω typical ON-state resistance (ron), supports rail-to-rail 0–5 V switching with 3.3-V V_CC, and enables bidirectional data flow with near-zero propagation delay (0.12 ns typical). It is used in USB interface isolation and differential signal bus gating where low capacitive loading (C_io(OFF) = 3.5 pF typical) and 5-V-tolerant I/Os are critical.

For engineers reviewing the SN74CB3Q3253PW datasheet, SN74CB3Q3253PW pinout, SN74CB3Q3253PW application, or SN74CB3Q3253PW equivalent, key selection criteria include its dual independent 1-of-4 channel architecture, I_off-enabled partial-power-down capability, 20 MHz maximum enable-switching frequency, and TSSOP-16 package compatibility with high-density PCB layouts.

Technical Context

The SN74CB3Q3253PW integrates two independent 1-of-4 analog/digital multiplexers, each with dedicated active-low output-enable (1OE, 2OE) and 2-bit select (S0, S1) inputs. Its charge-pump-enhanced FET switch architecture elevates gate voltage to maintain flat ron across V_CC (2.3–3.6 V) and input voltage (0–5.5 V), enabling consistent signal integrity up to 500 MHz.

Each channel supports bidirectional rail-to-rail switching without level translation, with 5-V-tolerant I/Os functional during power-up, power-down, or V_CC = 0 V. The device features undershoot clamp diodes on all control and data pins, I_off protection limiting backflow current to 1 µA at V_CC = 0 V, and thermal metrics including R_θJA = 112.7 °C/W (TSSOP).

Key Specifications

Pinout & Package

TSSOP-16 package (5.00 mm × 4.40 mm body size), thermally enhanced with exposed pad not connected internally; compatible with standard surface-mount reflow profiles (MSL Level-1).

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74CB3Q3253PW, SN74CB3Q3253PWR offers identical functionality with superior supply chain availability, while SN74CB3Q3253RGYR provides enhanced thermal dissipation in smaller footprint-both require no schematic change but may need layout revision for package-specific routing and thermal management.

Availability

SN74CB3Q3253PW is available at Aetrix Electronics and suitable for USB interface isolation, PCIe lane sharing, differential bus gating, and test access point switching requiring stable component supply and long-term obsolescence mitigation planning.

Supply support for SN74CB3Q3253PW 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 signal conditioning and interface solutions.

The SN74CB3Q3253PW belongs to TI's CB3Q family of high-bandwidth FET bus switches, engineered for low-distortion, rail-to-rail signal routing in broadband communications, networking infrastructure, and high-speed computing interfaces.

FAQ

What is the maximum operating frequency supported by the SN74CB3Q3253PW?

The SN74CB3Q3253PW supports signal bandwidth up to 500 MHz, verified by its high-bandwidth FET architecture and low 4 Ω typical ON-state resistance. This enables reliable operation in USB 2.0, PCIe Gen1, and LVDS applications where signal integrity at multi-hundred-MHz frequencies is essential. Performance remains stable across V_CC = 2.3–3.6 V and temperature range –40°C to +85°C.

Does the SN74CB3Q3253PW support 5-V tolerant I/Os when powered down?

Yes, the SN74CB3Q3253PW maintains 5-V tolerance on all data I/O pins (1A, 1B1–1B4, 2A, 2B1–2B4) even when V_CC = 0 V. This is enabled by integrated clamp diodes and I_off circuitry that limits reverse current to ≤1 µA, allowing safe interfacing with live 5-V buses during power sequencing or partial shutdown scenarios.

How does the charge pump in the SN74CB3Q3253PW improve switching performance?

The internal charge pump in the SN74CB3Q3253PW elevates the gate voltage of the pass transistors above V_CC, ensuring strong enhancement-mode conduction across the full 0–5.5 V I/O voltage range. This results in flat, low ON-state resistance (4 Ω typical) independent of input signal level-critical for minimizing insertion loss and maintaining signal fidelity in high-speed digital and analog routing.

Can the SN74CB3Q3253PW be used for analog signal switching?

Yes, the SN74CB3Q3253PW is explicitly qualified for both digital and analog applications, including low-distortion signal gating and differential bus isolation. Its rail-to-rail operation, low 3.5 pF OFF-state capacitance, and flat ron ensure minimal THD and signal attenuation-making it suitable for audio, video, and sensor signal path switching where linearity and bandwidth matter.

What is the thermal resistance (R_θJA) of the SN74CB3Q3253PW in its TSSOP package?

The SN74CB3Q3253PW in TSSOP-16 package has a junction-to-ambient thermal resistance (R_θJA) of 112.7 °C/W under standard JEDEC test conditions. This value assumes a 2-layer PCB with 1-in² copper pour; actual thermal performance improves with additional copper area, thermal vias, or airflow-important for sustained 500-MHz operation in enclosed enclosures.