Texas Instruments SN74CBTLV3251DR

Overview

SN74CBTLV3251DR from Texas Instruments is a low-voltage 1-of-8 FET multiplexer/demultiplexer in SOIC-16 package, featuring 5 Ω typical on-state resistance, rail-to-rail signal switching, and I_off partial-power-down protection. It operates from 2.3 V to 3.6 V, delivers sub-nanosecond propagation delay (0.15–0.25 ns), and supports high-speed data routing in server backplanes and industrial I/O subsystems.

For engineers reviewing the SN74CBTLV3251DR datasheet, SN74CBTLV3251DR pinout, SN74CBTLV3251DR application, or SN74CBTLV3251DR equivalent, key selection criteria include its 5 Ω switch R_on, guaranteed isolation during power-off via I_off, 8-channel bidirectional signal path, and compatibility with 2.5 V/3.3 V logic systems requiring minimal propagation delay and latch-up immunity exceeding 100 mA per JESD 78 Class II.

Technical Context

The SN74CBTLV3251DR implements eight independent FET transmission gates controlled by three binary select lines (S0–S2) and an active-low output-enable (OE). Its CMOS-based switch architecture enables bidirectional, rail-to-rail signal flow between the common A port and any of eight B ports (B1–B8), with no internal level-shifting or direction control logic.

Operation is fully specified across –40 °C to +85 °C at V_CC = 2.3–3.6 V. The I_off feature limits off-state current to ≤20 µA when V_CC = 0 V and any I/O is biased 0–3.6 V, preventing backdrive damage during partial power-down. OE must be pulled up to V_CC to ensure high-impedance state at power-up/down.

Key Specifications

Pinout & Package

SN74CBTLV3251DR uses a 16-pin SOIC (D) package measuring 9.90 mm × 3.91 mm, with standard 1.27 mm pitch and gull-wing leads. It is RoHS-compliant, moisture sensitivity level (MSL) 1, and rated for –40 °C to +85 °C operation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74CBTLV3251DR, SN74CBT3251PWR offers identical electrical performance in a smaller, thinner package ideal for dense layouts, while SN74LVC1G3157DCKR provides voltage flexibility and miniaturization at the cost of channel count and board-level integration efficiency.

Availability

SN74CBTLV3251DR is available at Aetrix Electronics and suitable for server backplane switching, industrial keypad polling, test equipment signal routing, and programmable I/O expansion requiring stable component supply and long-term industrial temperature support.

Supply support for SN74CBTLV3251DR 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-reliability logic and interface solutions.

The SN74CBTLV3251DR belongs to TI's CBTLV low-voltage FET switch family, designed specifically for high-speed, low-distortion signal routing in enterprise computing, industrial automation, and communications infrastructure where power efficiency and signal integrity are critical.

FAQ

What is the maximum operating temperature range for the SN74CBTLV3251DR?

The SN74CBTLV3251DR is rated for continuous operation from –40 °C to +85 °C ambient temperature. This industrial temperature range is validated per TI's thermal characterization and ensures reliable performance in server chassis, factory floor controllers, and outdoor networking equipment where ambient conditions exceed commercial limits. The SOIC package's R_θJA of 102.7 °C/W supports this rating with standard PCB copper pour.

Does the SN74CBTLV3251DR support bidirectional signal flow?

Yes, the SN74CBTLV3251DR supports fully bidirectional signal flow between the A port and any selected B_n port. Its FET-based transmission gate architecture imposes no inherent directionality - signals pass equally well from A to B_n or B_n to A, provided V_CC is within 2.3–3.6 V and OE is asserted low. This enables flexible use in data acquisition, bus sharing, and sensor interface applications.

How does the I_off feature protect the SN74CBTLV3251DR during partial power-down?

The I_off feature limits off-state current to ≤20 µA when V_CC = 0 V and any I/O terminal is biased between 0 V and 3.6 V. This prevents damaging back-current from powered subsystems into the unpowered SN74CBTLV3251DR, ensuring safe operation during staggered power sequencing in modular systems. The specification is verified per JEDEC JESD78 Class II latch-up testing.

What is the recommended pull-up resistor value for OE on the SN74CBTLV3251DR?

Texas Instruments specifies that OE must be tied to V_CC through a pull-up resistor to guarantee high-impedance state during power-up and power-down. The minimum resistor value depends on the current-sinking capability of the driving source; TI recommends verifying driver specs, but typical designs use 4.7 kΩ to 10 kΩ for 3.3 V systems. No maximum value is specified, though values >100 kΩ risk slow turn-on due to parasitic capacitance.

Can the SN74CBTLV3251DR be used with 1.8 V logic systems?

No, the SN74CBTLV3251DR is not rated for 1.8 V operation. Its absolute minimum V_CC is 2.3 V, and recommended operating range is strictly 2.3–3.6 V. Attempting to operate below 2.3 V may result in undefined switching behavior, excessive R_on, or failure to meet timing specifications. For 1.8 V systems, consider TI's SN74LVC1G3157 or similar LVC-family switches explicitly characterized down to 1.65 V.