Texas Instruments SN74CB3Q3253PWR

Overview

SN74CB3Q3253PWR from Texas Instruments is a dual 1-of-4 FET bus switch multiplexer–demultiplexer operating at 2.3 V to 3.6 V, delivering 4 Ω typical ON-state resistance, 500 MHz bandwidth, and 3.5 pF typical OFF-state I/O capacitance. It enables bidirectional rail-to-rail signal routing (0–5 V with 3.3-V V_CC) in high-speed digital interfaces such as USB and differential bus isolation.

For engineers reviewing the SN74CB3Q3253PWR datasheet, SN74CB3Q3253PWR pinout, SN74CB3Q3253PWR application, or SN74CB3Q3253PWR equivalent, key selection criteria include its 5-V tolerant I/Os during power-up/down, partial-power-down support via I_off, near-zero propagation delay (<0.18 ns), and compatibility with TTL/3.3-V/5-V CMOS control inputs.

Technical Context

The SN74CB3Q3253PWR integrates two independent 1-of-4 analog/digital multiplexers, each with active-low output-enable (1OE, 2OE) and 2-bit binary select (S0, S1) logic. Its charge-pump-enhanced FET architecture elevates gate voltage to maintain flat r_on across V_CC (2.3–3.6 V) and signal swing (0–5 V).

Each channel supports bidirectional data flow with no direction pin required; switching is controlled solely by OE and S inputs. The device features undershoot clamp diodes on all control and I/O pins, and I_off protection ensures no backflow current when V_CC = 0 V, enabling safe hot-insertion and partial-power-down operation.

Key Specifications

Pinout & Package

TSSOP-16 package (5.00 mm × 4.40 mm body size), thermally enhanced with exposed pad (not electrically connected), RoHS-compliant NiPdAu lead finish, MSL Level-1 (260°C, unlimited reflow).

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74CBTLV3253PWR and TS3DV642RTVR, the SN74CB3Q3253PWR uniquely delivers dual independent 1-of-4 topology with 4 Ω r_on, 3.5 pF C_io(OFF), and guaranteed 500 MHz operation - making it optimal for high-fidelity, high-speed bus multiplexing where channel granularity and signal fidelity are critical.

Availability

SN74CB3Q3253PWR is available at Aetrix Electronics and suitable for USB 2.0 interface design, video broadcasting transcoders, and industrial Ethernet PHY isolation requiring stable component supply and long-term production continuity.

Supply support for SN74CB3Q3253PWR 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-path solutions.

The SN74CB3Q3253PWR belongs to TI's CB3Q family of high-bandwidth FET bus switches, engineered specifically for low-distortion, rail-to-rail signal routing in high-speed digital and mixed-signal systems.

FAQ

What is the maximum signal frequency supported by the SN74CB3Q3253PWR?

The SN74CB3Q3253PWR is characterized for operation up to 500 MHz, verified through bandwidth testing and typical r_on/C_io performance. Real-world usable frequency depends on PCB layout, trace impedance, and load capacitance - TI recommends keeping total node capacitance ≤10 pF for full 500 MHz compliance. The SN74CB3Q3253PWR maintains signal integrity at USB 2.0 (480 Mbps) and HD-SDI (1.485 Gbps) rates when properly terminated.

Does the SN74CB3Q3253PWR support 5-V signals when V_CC is 2.5 V?

Yes, the SN74CB3Q3253PWR supports 0–5 V signals on all I/O ports (1A, 1B1–1B4, 2A, 2B1–2B4) regardless of V_CC voltage (2.3–3.6 V) and even when V_CC = 0 V. This 5-V tolerance is achieved via internal clamping and charge-pump circuitry, enabling seamless interfacing between mixed-voltage domains without level shifters. The SN74CB3Q3253PWR datasheet confirms VI/O ratings up to 7 V under absolute maximum conditions.

How does the I_off feature work in the SN74CB3Q3253PWR?

The I_off circuitry in the SN74CB3Q3253PWR actively disables all FET channels and blocks current flow when V_CC = 0 V, limiting leakage to ≤1 µA. This prevents back-driving of powered subsystems during hot-swap or partial-power-down events. Unlike passive high-Z states, I_off is an active protection mechanism validated per JESD78 Class II latch-up standards. The SN74CB3Q3253PWR maintains this behavior across –40°C to 85°C ambient temperature.

Can the SN74CB3Q3253PWR be used for analog signal switching?

Yes, the SN74CB3Q3253PWR is explicitly qualified for both digital and analog applications, including low-distortion signal gating and differential bus isolation. Its rail-to-rail operation (0–5 V), flat r_on (±10% variation), low THD (<–70 dB typical), and 3.5 pF C_io(OFF) make it suitable for audio, video, and sensor signal routing. TI's application report SCDA008 confirms analog performance metrics for the CB3Q family, and the SN74CB3Q3253PWR is referenced in USB and SDI analog-switching reference designs.

What is the recommended bypass capacitor for the SN74CB3Q3253PWR?

A 0.1-µF ceramic capacitor is required between V_CC (Pin 16) and GND (Pin 8), placed as close as possible to the device - ideally within 3 mm and connected via short, wide traces. TI specifies this value to suppress high-frequency supply noise generated by fast switching (f_OE ≤20 MHz) and maintain r_on stability. For systems with multiple SN74CB3Q3253PWR devices or high-current loads, adding a parallel 1-µF capacitor improves low-frequency decoupling. The SN74CB3Q3253PWR datasheet Figure 5 shows the exact placement guideline.