Texas Instruments SN74CB3Q3306ADCUR

Overview

SN74CB3Q3306ADCUR from Texas Instruments is a dual 1-bit FET bus switch optimized for high-bandwidth, low-distortion signal routing in 2.5-V/3.3-V systems. It features bidirectional rail-to-rail switching (0–5 V), 4 Ω typical ON-state resistance (ron), <0.2 ns propagation delay, and 5-V-tolerant I/Os with Ioff partial-power-down protection. It serves as a low-latency isolation switch in USB interface and differential signaling paths.

For engineers reviewing the SN74CB3Q3306ADCUR datasheet, SN74CB3Q3306ADCUR pinout, SN74CB3Q3306ADCUR application, or SN74CB3Q3306ADCUR equivalent, key selection criteria include ron flatness across voltage rails, sub-1 ns enable/disable timing, 3.5 pF OFF-state I/O capacitance, and VSSOP-8 (DCU) package compatibility with high-density PCB layouts.

Technical Context

The SN74CB3Q3306ADCUR implements two independent FET-based analog/digital bus switches, each controlled by dedicated OE inputs (1OE, 2OE). Its charge-pump gate drive enables consistent ron ≤6 Ω across 0–5 V I/O swing and 2.3–3.6 V VCC, supporting mixed-voltage domain bridging without level shifters.

Each switch supports bidirectional signal flow with near-zero propagation delay, 20 MHz maximum OE toggle frequency, and Ioff-enabled isolation during power-down-ensuring no backfeed current when VCC = 0 V and VI/O = 0–5.5 V.

Key Specifications

Pinout & Package

VSSOP-8 (DCU) package: 2.3 mm × 2.0 mm body, 0.5 mm pitch, 0.9 mm max height, exposed pad not present, RoHS-compliant NiPdAu lead finish, MSL Level-1.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74CB3Q3306ADCUR, SN74CBT3306CPW trades bandwidth and ron flatness for broader VCC range and lower cost, while TS3A24159DGSR offers lower ron and integrated control logic at the expense of 5-V tolerance and pin compatibility-requiring PCB redesign and signal integrity revalidation.

Availability

SN74CB3Q3306ADCUR is available at Aetrix Electronics and suitable for USB interface design, differential signal routing, bus isolation, and low-distortion analog gating requiring stable component supply and long-term production continuity.

Supply support for SN74CB3Q3306ADCUR 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 delivering analog, embedded processing, and connectivity solutions with emphasis on reliability, precision, and power efficiency.

The SN74CB3Q3306ADCUR belongs to TI's CB3Q family of high-bandwidth FET bus switches, engineered specifically for broadband communications, networking infrastructure, and data-intensive computing systems demanding minimal latency and distortion.

FAQ

What is the maximum operating frequency supported by the SN74CB3Q3306ADCUR for signal switching?

The SN74CB3Q3306ADCUR supports high-bandwidth signal paths up to 500 MHz, verified by its low 3.5 pF OFF-state I/O capacitance and 4 Ω typical ON-state resistance. This enables clean transmission of fast digital edges and analog waveforms without significant attenuation or phase shift. The device's 0.2 ns propagation delay further ensures timing-critical applications like USB 2.0 and LVDS remain within specification. Performance holds across 0–5 V signal swings when powered at 3.3 V.

Does the SN74CB3Q3306ADCUR support partial-power-down operation, and how does it behave when VCC = 0 V?

Yes, the SN74CB3Q3306ADCUR fully supports partial-power-down via its Ioff feature. When VCC = 0 V and VI/O = 0–5.5 V, the device limits reverse current to ≤1 mA, preventing backfeed into powered system sections. This behavior isolates unpowered domains during hot-swap, suspend, or firmware-controlled shutdown sequences. The high-impedance state remains stable without external biasing, making SN74CB3Q3306ADCUR suitable for systems requiring robust power sequencing.

Can the SN74CB3Q3306ADCUR interface between 1.8-V and 3.3-V logic domains without external level shifters?

Yes, the SN74CB3Q3306ADCUR supports 0–5.5 V signaling on all I/O ports regardless of VCC (2.3–3.6 V), enabling direct interfacing between 1.8-V, 2.5-V, 3.3-V, and 5-V logic families. Its rail-to-rail switching capability ensures full logic-level translation without distortion or timing penalty. For example, with VCC = 3.3 V, a 1.8-V input on 1A appears unchanged at 1B, and vice versa - eliminating the need for discrete level shifters in mixed-voltage USB, I²C, or GPIO expansion applications.

What is the recommended PCB layout practice for the SN74CB3Q3306ADCUR's VCC and GND connections?

TI specifies that SN74CB3Q3306ADCUR requires a 0.1 µF ceramic decoupling capacitor placed as close as possible to the VCC pin (Pin 5), with short, low-inductance traces to the GND pin (Pin 4). The GND connection must tie directly to the main system ground plane - not a split or islanded ground - to ensure stable charge-pump operation and minimize noise coupling into the high-bandwidth signal paths. Avoid routing high-speed signals under the device body, and maintain clearance around the DCU package per IPC-7351 land pattern guidelines.

How does the SN74CB3Q3306ADCUR differ from standard CMOS analog switches in terms of ON-state resistance behavior?

Unlike standard CMOS analog switches whose ron rises sharply near supply rails, the SN74CB3Q3306ADCUR uses an internal charge pump to elevate the gate voltage of its pass FETs, resulting in flat ron ≈4–6 Ω across the full 0–5 V I/O range. This eliminates signal-dependent distortion and preserves waveform fidelity for both digital and analog signals. Measured ron variation is <1 Ω from 0 V to 5 V at VCC = 3.3 V, whereas conventional switches may exhibit >10× ron increase near VCC or GND - making SN74CB3Q3306ADCUR uniquely suited for high-fidelity signal gating.