Texas Instruments SN74CB3Q6800DGVR

Overview

SN74CB3Q6800 from Texas Instruments is a 10-bit FET bus switch with precharged B-port outputs, designed for high-bandwidth bidirectional signal routing in 2.5-V/3.3-V systems. It delivers rail-to-rail switching, 4.5 Ω typical ON-state resistance (ron), <0.225 ns propagation delay, and 5-V-tolerant I/Os - enabling PCI Hot Plug, memory interleaving, and low-distortion analog/digital gating.

For engineers reviewing the SN74CB3Q6800 datasheet, SN74CB3Q6800 pinout, SN74CB3Q6800 application, or SN74CB3Q6800 equivalent, key selection criteria include precharge bias (BIASV) support for live insertion noise suppression, Ioff-enabled partial-power-down operation, 3.5 pF OFF-state I/O capacitance, and TVSOP-24 package compatibility with high-density PCB layouts.

Technical Context

The SN74CB3Q6800 employs an internal charge pump to elevate the gate voltage of its pass transistors, ensuring flat, low ron across 0–5 V I/O signaling levels (2.3–3.6 V VCC). Its single ON control input enables/disables all 10 A↔B channels simultaneously, with bidirectional conduction and near-zero propagation delay.

When disabled (ON = high), the B-port outputs are actively precharged to BIASV via ~10-kΩ equivalent resistance - minimizing signal distortion during hot-plug events. The device supports 5-V-tolerant I/Os regardless of VCC state (powered up/down), and integrates undershoot clamp diodes on all data and control pins for robust ESD and transient immunity.

Key Specifications

Pinout & Package

SN74CB3Q6800 is packaged in a 24-pin TVSOP (DGV) with 0.4-mm pitch, 1.2-mm max height, and exposed metal thermal pad. The package is RoHS-compliant, moisture-sensitivity Level-1 (unlimited reflow), and optimized for automated SMT assembly.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74CBT6800DGVR and SN74LVC1G3157DCKR, the SN74CB3Q6800 uniquely combines 10-bit integration, BIASV-controlled precharge, and charge-pump-enhanced ron - making it the only option qualified for PCI Hot Plug and high-fidelity memory bus isolation in compact TVSOP layouts.

Availability

SN74CB3Q6800 is available at Aetrix Electronics and suitable for PCI interface design, memory interleaving architectures, and bus isolation circuits requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant TVSOP packaging.

Supply support for SN74CB3Q6800 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 decades of expertise in high-speed interface solutions.

The SN74CB3Q6800 belongs to TI's CB3Q family of high-bandwidth FET bus switches, engineered specifically for low-distortion, hot-plug-capable signal routing in communications infrastructure, networking gear, and data-intensive computing platforms.

FAQ

What is the maximum operating frequency supported by the SN74CB3Q6800?

The SN74CB3Q6800 supports a maximum switching frequency of 20 MHz on its ON control input under specified conditions (VO > VCC, VI = 5 V, RL ≥ 1 MΩ, CL = 0). Its high-bandwidth data path handles signals up to 500 MHz, validated for integrity in applications like memory interleaving and differential signal gating where edge fidelity is critical. This performance stems from its low 3.5-pF OFF-state capacitance and flat 4.5-Ω ON-resistance.

How does the BIASV pin function in the SN74CB3Q6800?

The BIASV pin on the SN74CB3Q6800 provides an external bias voltage (0–5 V) used to precharge the B-port outputs to a defined DC level when the device is disabled (ON = high) or powered down (VCC = 0 V). This precharge minimizes signal distortion and prevents live-insertion glitches by aligning the B-port voltage with the input threshold of downstream receivers. For PCI applications, BIASV is typically set to 1.5 V or 2.0 V to match standard receiver thresholds.

Can the SN74CB3Q6800 operate with VCC = 0 V while maintaining I/O protection?

Yes, the SN74CB3Q6800 maintains 5-V tolerance on all A/B I/O pins and control inputs even when VCC = 0 V, thanks to integrated undershoot clamp diodes and Ioff circuitry. When powered down, Ioff limits reverse current to ≤1 µA, preventing damaging backflow into powered subsystems. This behavior is explicitly characterized in the datasheet's Absolute Maximum Ratings and Electrical Characteristics tables - confirming safe operation during partial-power-down sequences.

What is the recommended layout practice for the SN74CB3Q6800 TVSOP package?

For the SN74CB3Q6800 in TVSOP-24 (DGV) package, TI recommends a non-solder-mask-defined (NSMD) land pattern with 0.4-mm pitch, 0.23-mm pad width, and 1.4-mm pad length. A 0.125-mm stencil aperture matching the pad dimensions ensures optimal solder paste release. The exposed metal thermal pad beneath the package must be connected to a solid GND plane via ≥4 thermal vias (0.3-mm diameter) to manage power dissipation and improve signal integrity.

Does the SN74CB3Q6800 support rail-to-rail analog signal switching?

Yes, the SN74CB3Q6800 supports true rail-to-rail analog signal switching across 0–5 V on both A and B ports, enabled by its charge-pump architecture and FET-based topology. Its low 4.5-Ω ron and 3.5-pF OFF-state capacitance preserve signal amplitude and edge rate - verified in TI's application report SCDA008 for CBT/CB3T/CB3Q families. This makes the SN74CB3Q6800 suitable for low-distortion analog gating in test instrumentation and mixed-signal systems.