Texas Instruments SN74CB3Q3253RGYR

Overview

SN74CB3Q3253RGYR from Texas Instruments is a dual 1-of-4 FET multiplexer–demultiplexer bus switch 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 SN74CB3Q3253RGYR datasheet, SN74CB3Q3253RGYR pinout, SN74CB3Q3253RGYR application, or SN74CB3Q3253RGYR equivalent, this device supports critical timing-sensitive signal gating, partial-power-down operation via I_off, and 5-V tolerant I/Os during both powered and unpowered states - key for hot-swap and mixed-voltage system design.

Technical Context

The SN74CB3Q3253RGYR integrates two independent 1-of-4 analog/digital multiplexers, each with active-low output-enable (1OE, 2OE) and 2-bit binary select (S0, S1), enabling simultaneous channel selection across two 4-channel banks. Its charge-pump gate drive ensures flat r_on over voltage and temperature, supporting near-zero propagation delay (0.12 ns typical) and minimal signal distortion.

Each channel features bidirectional data flow between common A ports (1A, 2A) and B-side I/Os (1B1–1B4, 2B1–2B4), with undershoot clamp diodes on all control and data pins, and I_off protection that isolates ports when V_CC = 0 V - essential for system-level power sequencing and backdrive prevention.

Key Specifications

Pinout & Package

VQFN-16 (RGY) package: 4.00 mm × 3.50 mm body, 0.5-mm pitch, exposed thermal pad for enhanced heat dissipation in compact high-density designs.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74CBTLV3253PWR and TS3DV642RTVR, SN74CB3Q3253RGYR delivers superior high-frequency performance (500 MHz vs. ≤300 MHz), lower ON-resistance (4 Ω vs. ≥5 Ω), and guaranteed I_off-enabled partial-power-down - making it optimal for space-constrained, mixed-voltage, timing-critical multiplexing.

Availability

SN74CB3Q3253RGYR is available at Aetrix Electronics and suitable for USB interface design, differential bus isolation, video broadcasting transcoders, and industrial I/O multiplexing requiring stable component supply and long-term production continuity.

Supply support for SN74CB3Q3253RGYR 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 solutions, with decades of expertise in high-speed signal integrity and power-efficient logic design.

SN74CB3Q3253RGYR belongs to TI's CB3Q family of high-bandwidth FET bus switches, engineered specifically for low-distortion, rail-to-rail signal gating in USB, video, and industrial communication systems operating across mixed voltage domains.

FAQ

What is the maximum signal frequency supported by SN74CB3Q3253RGYR?

The SN74CB3Q3253RGYR supports up to 500 MHz bandwidth, verified under load conditions with matched impedances and proper layout. This enables reliable use in USB 2.0 (480 Mbps), DDR1/2 clock distribution, and HD video parallel buses. Performance depends on PCB trace quality, termination, and capacitive loading - actual system bandwidth may be lower if layout introduces excessive parasitics.

Does SN74CB3Q3253RGYR support 5-V signals when powered at 3.3 V?

Yes, SN74CB3Q3253RGYR has 5-V tolerant I/Os on all B-side ports (1B1–1B4, 2B1–2B4) and A ports (1A, 2A), whether powered at 2.5 V, 3.3 V, or any V_CC within 2.3–3.6 V. This allows direct interfacing with 5-V peripherals without level shifters, even during power-up or power-down sequences.

How does the I_off feature work in SN74CB3Q3253RGYR?

SN74CB3Q3253RGYR's I_off circuitry actively blocks current flow between I/O ports when V_CC = 0 V, limiting backdrive current to ≤1 µA. This protects upstream drivers during hot-swap events or partial system power-down, and is intrinsic to the FET structure - no external bias or control is needed beyond tying OE high to disable channels.

What is the thermal performance of SN74CB3Q3253RGYR in its VQFN package?

SN74CB3Q3253RGYR in the RGY (VQFN-16) package has a junction-to-board thermal resistance (R_θJB) of 23.3°C/W and junction-to-ambient (R_θJA) of 45.7°C/W with standard JEDEC 2-layer board layout. The exposed thermal pad must be soldered to a solid copper pour for optimal heat dissipation, especially under sustained 64-mA per-channel loads.

Can SN74CB3Q3253RGYR be used for analog signal switching?

Yes, SN74CB3Q3253RGYR is specified for both digital and analog applications, including low-distortion signal gating and differential bus isolation. Its flat 4-Ω r_on, low 3.5-pF OFF-capacitance, and rail-to-rail voltage handling (0–5 V) support analog signals up to ~100 MHz with minimal THD and insertion loss - confirmed in TI's CBT-C/CB3T/CB3Q application report SCDA008.