Texas Instruments SN74CB3T16211DLR

Overview

SN74CB3T16211DLR from Texas Instruments is a 24-bit FET bus switch IC with dual 12-bit configurable channels, 5-V tolerant I/Os, 2.3–3.6 V supply operation, 5 Ω typical ON-state resistance, and bidirectional near-zero-delay signal routing for mixed-voltage system interconnect. It enables level translation between 5-V, 3.3-V, and 2.5-V logic domains in PCI interfaces and bus isolation circuits.

For engineers reviewing the SN74CB3T16211DLR datasheet, SN74CB3T16211DLR pinout, SN74CB3T16211DLR application, or SN74CB3T16211DLR equivalent, key selection criteria include its 5-V-tolerant I/O capability with powered-down isolation (Ioff), 5 pF off-state capacitance, dual independent OE control, 0.25 ns typical propagation delay at 3.3 V, and SSOP-56 package compatibility with legacy board layouts.

Technical Context

The SN74CB3T16211DLR implements two independent 12-bit FET-based analog switches controlled by separate 1OE and 2OE inputs, supporting bidirectional data flow with no direction pin required. Its voltage-tracking output architecture ensures output voltage follows VCC, enabling seamless 5-V-to-3.3-V and 5-V/3.3-V-to-2.5-V level shifting across all 24 I/Os.

Each channel operates with rail-to-rail signal swing, supports partial-power-down via Ioff (≤10 μA leakage when VCC = 0), and features undershoot clamp diodes on all data and control inputs. The device maintains high-impedance isolation during power-up/down when OE is pulled up to VCC, satisfying robust system-level sequencing requirements.

Key Specifications

Pinout & Package

SN74CB3T16211DLR uses a 56-pin SSOP (DL) package measuring 13.9 mm × 7.9 mm × 1.2 mm max height, with 0.5-mm lead pitch and JEDEC MO-153 registration. Pin 1 is located in quadrant Q1 per tape-and-reel orientation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74CB3T16211DLR, SN74CBT16211DLR lacks Ioff and mixed-voltage support, while SN74LVC16245ADGGR introduces directionality and latency-making SN74CB3T16211DLR uniquely suited for transparent, low-skew, power-aware interconnect in heterogeneous voltage systems.

Availability

SN74CB3T16211DLR is available at Aetrix Electronics and suitable for PCI interface design, multi-voltage memory subsystems, and hot-swappable backplane modules requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant packaging.

Supply support for SN74CB3T16211DLR 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 digital signal technologies, with decades of expertise in high-speed interface solutions.

The SN74CB3T16211DLR belongs to TI's Widebus™ family of FET bus switches, designed specifically for low-latency, low-power, mixed-voltage interconnect in computing, communications, and industrial control systems.

FAQ

What is the maximum operating frequency supported by the SN74CB3T16211DLR?

The SN74CB3T16211DLR does not specify a maximum clock frequency, as it functions as an analog bus switch-not a clocked device. Its 0.25 ns typical propagation delay at 3.3 V enables reliable operation with edge rates corresponding to >1 GHz signal bandwidths. System-level timing depends on load capacitance and trace impedance; for 50-pF loads, the RC time constant with 5-Ω ron yields <0.25 ns delay, making SN74CB3T16211DLR suitable for DDR2/DDR3 address/control buses and PCI-X signaling.

Can the SN74CB3T16211DLR be used with a 2.5-V VCC to translate 5-V inputs to 2.5-V outputs?

Yes, the SN74CB3T16211DLR explicitly supports 5-V-to-2.5-V level translation when VCC = 2.5 V. Per the datasheet's DC voltage-translation characteristics and Figure 1, the output voltage tracks VCC, so a 5-V input applied to any A or B port produces a 2.5-V output referenced to the 2.5-V VCC rail. This capability is validated across the full –40°C to 85°C temperature range and requires no external components-confirming SN74CB3T16211DLR's suitability for mixed-mode 2.5-V system designs.

Does the SN74CB3T16211DLR require external pull-up resistors on its I/O ports?

No, the SN74CB3T16211DLR does not require external pull-up resistors on its I/O ports for basic level translation. Its internal pullup current source maintains output voltage at VCC when the switch is ON and the input ≥ VCC – 1 V. However, if an I/O port is connected to a pulldown resistor (e.g., for open-drain emulation), the output voltage may sag below VCC; in that case, a pullup to VCC-not ground-is recommended. This behavior is intrinsic to SN74CB3T16211DLR's architecture and documented in the "DESCRIPTION" section.

How does the Ioff feature of the SN74CB3T16211DLR protect downstream circuitry during power-down?

The Ioff feature of the SN74CB3T16211DLR limits leakage current to ≤10 μA when VCC = 0 V and any I/O port is biased between 0–5.5 V, preventing damaging backdrive current from live system traces into unpowered sections. This isolation ensures no current flows through the FET channel in either direction during partial-power-down states-critical for hot-swap compliance and system-level fault containment. Test data in the Electrical Characteristics table confirms this performance, making SN74CB3T16211DLR robust for modular, field-upgradeable hardware.

Is the SN74CB3T16211DLR pin-compatible with other members of the SN74CB3T16xxx family?

Yes, the SN74CB3T16211DLR shares identical pinout and package (SSOP-56) with SN74CB3T16210DLR and SN74CB3T16245DLR, differing only in internal channel configuration (2×12-bit vs. 1×24-bit vs. 2×12-bit with different OE mapping). All three support the same VCC range, Ioff, and 5-V tolerance. Layout reuse is fully supported-no PCB changes required-when migrating between these variants for design optimization or inventory flexibility.