Texas Instruments SN74CB3Q3253DBQR

Overview

SN74CB3Q3253DBQR from Texas Instruments is a dual 1-of-4 FET multiplexer–demultiplexer bus switch optimized for high-bandwidth signal routing in 2.5-V to 3.3-V systems. It delivers rail-to-rail switching (0–5 V with 3.3-V V_CC), 4 Ω typical ON-state resistance, <0.18 ns propagation delay, and 500 MHz bandwidth-enabling low-distortion USB interface and differential bus isolation.

For engineers reviewing the SN74CB3Q3253DBQR datasheet, SN74CB3Q3253DBQR pinout, SN74CB3Q3253DBQR application, or SN74CB3Q3253DBQR equivalent, key selection criteria include 5-V tolerant I/Os under powered-up/down conditions, I_off-enabled partial-power-down operation, bidirectional zero-delay data flow, and SSOP-16 package compatibility with industrial temperature range (–40°C to +85°C).

Technical Context

The SN74CB3Q3253DBQR integrates two independent 1-of-4 analog/digital multiplexers, each with active-low output enables (1OE, 2OE) and 2-bit binary select inputs (S0, S1). Its charge-pump-enhanced FET architecture elevates gate voltage to maintain flat r_on across input voltage range, enabling rail-to-rail signal pass-through without level-shifting circuitry.

Each channel supports bidirectional, near-zero-propagation-delay switching between common port (1A/2A) and four I/O ports (1B1–1B4 / 2B1–2B4), with 3.5 pF typical OFF-state I/O capacitance and 5-V tolerant clamped inputs-critical for mixed-voltage system interconnects and hot-swap-capable interfaces.

Key Specifications

Pinout & Package

SN74CB3Q3253DBQR uses a 16-pin SSOP (DBQ) package measuring 4.90 mm × 3.90 mm with exposed thermal pad, rated for –40°C to +85°C operation and compliant with Level-2-260°C-1-year MSL handling.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74CB3Q3253DBQR, SN74CBT3244DBQR trades bandwidth and voltage range for lower cost, while TS3DV642RTVR offers scalability over channel count at the expense of package size and I/O capacitance-making SN74CB3Q3253DBQR optimal for compact, mixed-voltage, high-fidelity signal routing.

Availability

SN74CB3Q3253DBQR is available at Aetrix Electronics and suitable for USB interface design, differential bus isolation, video broadcasting transcoder development, and industrial control backplane reconfiguration requiring stable component supply across extended temperature and mixed-voltage environments.

Supply support for SN74CB3Q3253DBQR 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 broad industrial, automotive, and communications portfolio coverage.

The SN74CB3Q3253DBQR belongs to TI's CB3Q bus switch family, engineered for high-bandwidth, low-distortion signal routing in mixed-voltage digital and analog systems-including USB, video, and industrial backplane applications.

FAQ

What is the maximum signal frequency supported by the SN74CB3Q3253DBQR?

The SN74CB3Q3253DBQR supports signal frequencies up to 500 MHz, verified under recommended operating conditions (V_CC = 3.3 V, T_A = 25°C). This bandwidth enables reliable routing of USB 2.0 (480 Mbps), LVDS, and other high-speed serial signals without measurable attenuation or phase distortion in properly terminated traces.

Does the SN74CB3Q3253DBQR require external level shifters when interfacing 5-V signals with a 3.3-V supply?

No, the SN74CB3Q3253DBQR does not require external level shifters. Its I/O ports are 5-V tolerant whether the device is powered (2.3–3.6 V) or unpowered, and it supports rail-to-rail switching-allowing 0–5 V signals to pass through with 3.3-V V_CC while maintaining signal integrity and timing accuracy.

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

The I_off feature in the SN74CB3Q3253DBQR actively blocks current flow between powered and unpowered domains. When V_CC = 0 V, leakage is limited to 1 µA max, preventing damaging backfeed currents from downstream 5-V sources into upstream 3.3-V logic-critical for hot-swap and modular power-gating architectures.

What is the purpose of the charge pump in the SN74CB3Q3253DBQR?

The integrated charge pump in the SN74CB3Q3253DBQR elevates the gate voltage of the internal FET pass transistors, ensuring low and flat ON-state resistance (r_on ≈ 4 Ω) across the full 0–5 V input voltage range. This eliminates r_on variation-induced signal distortion and enables consistent propagation delay for high-fidelity analog and digital signal routing.

Can the SN74CB3Q3253DBQR be used in bidirectional data paths without additional control logic?

Yes, the SN74CB3Q3253DBQR supports fully bidirectional data flow with near-zero propagation delay in either direction-no direction-control pins or external logic required. Each channel operates symmetrically between A and B ports, making it ideal for bus-sharing, shared-memory, and peer-to-peer interconnect applications.