Texas Instruments SN74CB3T16211DGVR

Overview

SN74CB3T16211 from Texas Instruments is a 24-bit FET bus switch IC supporting mixed-mode voltage translation (5 V ↔ 3.3 V ↔ 2.5 V), with dual 12-bit independent channels, 5-V-tolerant I/Os, and near-zero propagation delay (0.15 ns typical at 3.3 V). It enables bidirectional signal routing in PCI interfaces, level-shifting backplanes, and low-power portable systems.

For engineers reviewing the SN74CB3T16211 datasheet, SN74CB3T16211 pinout, SN74CB3T16211 application, or SN74CB3T16211 equivalent, key selection considerations include its 5-V-tolerant I/O capability under powered-down conditions, Ioff partial-power-down support, ON-state resistance (5 Ω typ), 2.3–3.6 V VCC range, and TVSOP-56 (DGV) package compatibility with high-density PCB layouts.

Technical Context

The SN74CB3T16211 implements two independent 12-bit FET-based analog switches controlled by separate OE inputs (1OE, 2OE), enabling flexible channel partitioning as either dual 12-bit or single 24-bit configurations. Each switch path features TTL-compatible control logic and voltage-tracking output translation that follows VCC.

Its architecture supports true bidirectional data flow without direction pins, leverages undershoot clamp diodes on all I/Os, and guarantees isolation during power-up/down via Ioff protection-preventing backflow current when VCC = 0 V and I/Os are biased to 0–5 V.

Key Specifications

Pinout & Package

SN74CB3T16211 is packaged in a 56-pin TVSOP (DGV) with 0.4-mm pitch, 6.2-mm width, and 1.2-mm max height-optimized for automated assembly and thermal performance in space-constrained designs.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74CB3T16211, SN74CBTLV3244PWR lacks voltage translation and Ioff, limiting use to single-rail designs, while SN74AVC16T245DGGR adds direction control overhead and removes powered-down isolation-making SN74CB3T16211 optimal for compact, mixed-voltage, hot-pluggable interconnects requiring zero-latency transparency and fail-safe power sequencing.

Availability

SN74CB3T16211 is available at Aetrix Electronics and suitable for PCI interface design, server backplane isolation, and low-power portable equipment requiring stable component supply and long-term production continuity.

Supply support for SN74CB3T16211 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 and industrial-grade reliability.

The SN74CB3T16211 belongs to TI's Widebus™ family of high-speed bus switches, engineered specifically for low-latency, mixed-voltage signal routing in computing, communications, and industrial infrastructure applications.

FAQ

What is the maximum operating frequency supported by the SN74CB3T16211?

The SN74CB3T16211 does not specify a hard maximum clock frequency but delivers 0.15 ns typical propagation delay at 3.3 V, enabling reliable operation in parallel buses exceeding 200 MHz. Signal integrity depends on trace length, load capacitance (<5 pF OFF), and termination-designs should maintain total path capacitance ≤30 pF for optimal eye diagram performance. The SN74CB3T16211 is commonly deployed in PCIe Gen1 interposers and DDR2 memory expansion links.

Does the SN74CB3T16211 require external pull-up resistors on its I/O lines?

The SN74CB3T16211 includes internal pull-up current sources on I/O ports to maintain VCC-level outputs when enabled and driven high, but external pull-ups are recommended when driving pulldown loads to prevent output droop. For guaranteed VCC-level logic high under all conditions-including low-frequency or high-impedance loads-a 10-kΩ pull-up to VCC is advised on each B-port line. The SN74CB3T16211 datasheet explicitly warns against using pulldown resistors alone due to this behavior.

Can the SN74CB3T16211 be used for unidirectional signal isolation?

Yes-the SN74CB3T16211 supports unidirectional use by connecting signals only to A-side or B-side pins and leaving the opposite side unused or terminated. Its bidirectional architecture imposes no penalty in unidirectional mode, and the 5-V tolerance, low ron (5 Ω), and 5-pF OFF capacitance remain fully applicable. In such configurations, SN74CB3T16211 provides superior isolation versus standard buffers due to its true high-Z OFF state and Ioff protection during power loss.

What is the thermal resistance (θJA) of the SN74CB3T16211 in the TVSOP (DGV) package?

The SN74CB3T16211 in the TVSOP-56 (DGV) package has a junction-to-ambient thermal resistance (θJA) of 48 °C/W, measured per JESD51-7 under standard 1-inch² copper pad conditions. This value assumes no additional heatsinking; actual board-level θJA will improve with enhanced copper area, thermal vias, or airflow. The SN74CB3T16211's low ICC (70 μA max) and minimal dynamic power dissipation ensure junction temperatures remain well within limits even in sealed enclosures at 85°C ambient.

How does the SN74CB3T16211 handle undershoot or ESD events on its I/O pins?

The SN74CB3T16211 integrates undershoot clamp diodes on all data I/O pins, rated to sink –50 mA of clamp current for VI/O < 0 V, protecting against transients down to –1.2 V. It is tested to JEDEC JESD22-A114B (2000-V HBM) and JESD22-C101 (1000-V CDM) ESD standards. These clamps operate independently of VCC state-ensuring protection remains active even during power-down-making the SN74CB3T16211 suitable for industrial I/O and docking station applications exposed to frequent electrostatic discharge.