Texas Instruments 74CB3Q3305DCURG4

Overview

74CB3Q3305DCURG4 from Texas Instruments is a dual 1-bit FET bus switch optimized for high-bandwidth, level-translating signal routing in mixed-voltage systems. It supports bidirectional 0–5 V signaling with 3.3 V V_CC, delivers 3 Ω typical ON-state resistance (r_on), <0.15 ns propagation delay, and 500 MHz bandwidth-enabling use in USB interface isolation and optical networking data paths.

For engineers reviewing the 74CB3Q3305DCURG4 datasheet, 74CB3Q3305DCURG4 pinout, 74CB3Q3305DCURG4 application, or 74CB3Q3305DCURG4 equivalent, key selection criteria include 5-V-tolerant I/Os under powered-up/down conditions, I_off-enabled partial-power-down protection, low 3.5 pF OFF-state capacitance, and VSSOP-8 package compatibility with space-constrained PCB layouts.

Technical Context

The 74CB3Q3305DCURG4 implements two independent FET-based switches with charge-pump gate drive to maintain flat r_on across 2.3–3.6 V V_CC and –40°C to 85°C. Each switch features separate OE control (1OE/2OE), enabling channel-level enable/disable without affecting the other path.

Its I_off circuitry blocks backflow current when V_CC = 0 V, ensuring isolation during power-down. The device operates with TTL- or CMOS-compatible control inputs and supports input voltages beyond supply-e.g., 0–5 V on I/O ports while V_CC = 3.3 V-making it suitable for voltage-level bridging between 5 V controllers and 3.3 V peripherals.

Key Specifications

Pinout & Package

VSSOP-8 (DCU) package: 2.00 mm × 3.10 mm body, 0.5 mm pitch, lead-free (NIPDAU), MSL Level-1, –40°C to +85°C operating range.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74CB3Q3245PWR and TS3A24159DGSR, the 74CB3Q3305DCURG4 uniquely balances per-channel control, 5-V tolerance under zero-V_CC, and flat r_on for mixed-voltage digital signal routing-making it optimal for modular, hot-pluggable telecom and networking interfaces requiring both flexibility and robustness.

Availability

74CB3Q3305DCURG4 is available at Aetrix Electronics and suitable for USB interface isolation, optical networking data paths, WiMAX baseband switching, and IP phone signal multiplexing requiring stable component supply across industrial temperature ranges.

Supply support for 74CB3Q3305DCURG4 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 for industrial, automotive, and communications markets.

The CB3Q family-including 74CB3Q3305DCURG4-is designed specifically for high-bandwidth, low-distortion signal routing in broadband communications infrastructure, where voltage-level translation, power-domain isolation, and signal integrity preservation are critical.

FAQ

What is the maximum signal frequency supported by the 74CB3Q3305DCURG4?

The 74CB3Q3305DCURG4 supports signal frequencies up to 500 MHz, as verified by TI's characterization under recommended operating conditions. This bandwidth is enabled by its low 3.5 pF OFF-state capacitance and 3 Ω typical ON-state resistance, which jointly minimize signal attenuation and phase distortion. Performance remains stable across the full 2.3–3.6 V V_CC range and –40°C to +85°C temperature span.

Does the 74CB3Q3305DCURG4 support level translation between 5 V and 3.3 V domains?

Yes, the 74CB3Q3305DCURG4 supports bidirectional level translation: it accepts 0–5 V signals on its A/B ports while operating from a 3.3 V V_CC, and also handles 0–3.3 V signals with 2.5 V V_CC. This is achieved through 5-V-tolerant I/O structures and internal charge-pump gate drive, eliminating the need for external level-shifting components in mixed-voltage interconnects.

How does the I_off feature protect the 74CB3Q3305DCURG4 during partial power-down?

The I_off circuitry in the 74CB3Q3305DCURG4 actively blocks current flow between A/B ports when V_CC = 0 V, preventing damaging backfeed from live 5 V buses into unpowered subsystems. Measured at 1 µA maximum leakage, this feature ensures safe hot-plug operation and meets JESD78 Class II latch-up immunity requirements-critical for modular telecom and networking equipment.

What is the recommended bypass capacitor for the 74CB3Q3305DCURG4 V_CC pin?

A 0.1 µF ceramic capacitor is recommended for the 74CB3Q3305DCURG4 V_CC pin, placed as close as possible to the pin with minimal trace length. This value is specified in TI's layout guidelines to suppress high-frequency noise and stabilize the internal charge pump. For systems with stringent EMI requirements, adding a parallel 1 µF capacitor further improves low-frequency decoupling without compromising high-speed performance.

Can the 74CB3Q3305DCURG4 be used in analog signal switching applications?

Yes, the 74CB3Q3305DCURG4 is suitable for analog signal switching up to ~100 MHz, thanks to its low 3 Ω r_on, flat r_on vs. voltage/temperature, and 3.5 pF OFF-state capacitance. It maintains low THD and preserves signal fidelity in audio, baseband, and low-speed RF paths. However, for precision analog applications requiring sub-0.1% gain error or >10-bit resolution, dedicated analog switches with guaranteed r_on matching should be evaluated alongside the 74CB3Q3305DCURG4.