Texas Instruments SN74CBTLV3251D

Overview

SN74CBTLV3251D 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-0.25 ns propagation delay, and is used for high-speed data routing in enterprise computing backplanes and wired networking switches.

For engineers reviewing the SN74CBTLV3251D datasheet, SN74CBTLV3251D pinout, SN74CBTLV3251D application, or SN74CBTLV3251D equivalent, key selection criteria include guaranteed 5 Ω r_on at 2.5 V/3.3 V, −40 °C to 85 °C industrial temperature range, I_off leakage ≤20 µA at V_CC = 0 V, and SOIC-16 thermal resistance R_θJA = 102.7 °C/W.

Technical Context

The SN74CBTLV3251D implements eight bidirectional analog/digital FET switches controlled by three binary select lines (S0–S2) and an active-low output-enable (OE). Its CMOS-compatible control logic drives internal transmission gates with minimal charge injection and no DC path between ports when disabled.

It supports rail-to-rail signal pass-through across all I/O pins (A, B1–B8), maintains high-impedance isolation during power-off via I_off, and requires OE tied to V_CC through a pullup resistor to ensure defined state at power-up. Latch-up immunity exceeds 100 mA per JESD78 Class II.

Key Specifications

Pinout & Package

SN74CBTLV3251D uses a 16-pin SOIC (D) package measuring 9.90 mm × 3.91 mm with standard 1.27 mm pitch. Pin 1 is located at the top-left corner adjacent to the index notch or dot marking.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 1-of-8 FET multiplexer applications.

Compared with SN74CBTLV3257D and 74LVC1G3157DP, the SN74CBTLV3251D provides unique 8-channel density in SOIC-16 with lowest r_on and highest channel integration-critical for backplane signal consolidation where board area and interconnect loss are primary constraints.

Availability

SN74CBTLV3251D is available at Aetrix Electronics and suitable for datacenter backplane switching, industrial Ethernet PHY multiplexing, and wired networking line card expansion requiring stable component supply across extended product lifecycles.

Supply support for SN74CBTLV3251D 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 solutions with over 90 years of innovation in high-reliability IC design.

The SN74CBTLV3251D belongs to TI's CBTLV logic family, engineered for low-voltage, high-speed signal routing in infrastructure equipment where signal fidelity, power efficiency, and industrial temperature operation are mandatory.

FAQ

What is the maximum continuous current rating per channel for the SN74CBTLV3251D?

The SN74CBTLV3251D supports a continuous channel current of 128 mA per switch, as specified in its Absolute Maximum Ratings table. This rating applies across the full operating temperature range and ensures reliable conduction without thermal runaway when used within recommended V_CC and ambient conditions. The SN74CBTLV3251D maintains this capability while delivering 5 Ω typical on-resistance at 2.5 V and 3.3 V supplies.

Does the SN74CBTLV3251D require external pull-up resistors on its control pins?

Yes - the OE (output-enable) pin of the SN74CBTLV3251D must be tied to V_CC through an external pullup resistor to guarantee high-impedance state during power-up and power-down transitions. The minimum resistor value depends on the current-sinking capability of the driving source, but typical values range from 4.7 kΩ to 10 kΩ. Control inputs S0–S2 do not require pullups if actively driven, but floating states must be avoided per TI's design guidelines.

Can the SN74CBTLV3251D operate with a 1.8 V supply?

No - the SN74CBTLV3251D is not rated for 1.8 V operation. Its Recommended Operating Conditions specify a minimum V_CC of 2.3 V and maximum of 3.6 V. Operation below 2.3 V may result in undefined logic thresholds, increased r_on, or failure to meet timing specifications. For 1.8 V systems, TI recommends alternatives such as the SN74LVC1G3157 or SN74AUC2G66, which are explicitly characterized down to 1.65 V.

How does the I_off feature protect the SN74CBTLV3251D during partial power-down?

The I_off feature in the SN74CBTLV3251D disables current flow between I/O terminals when V_CC = 0 V, limiting leakage to ≤20 µA even with up to 3.6 V applied to B-port pins. This prevents backflow current from powered downstream circuits into the unpowered SN74CBTLV3251D, avoiding latch-up or damage. The SN74CBTLV3251D achieves this through internal transistor cutoff design, validated per JESD78 Class II standards.

Is the SN74CBTLV3251D pin-compatible with other packages in the same family?

No - the SN74CBTLV3251D (SOIC-16) shares identical functionality and logic behavior with SN74CBTLV3251DBQR (SSOP-16), SN74CBTLV3251PWR (TSSOP-16), and SN74CBTLV3251RGYR (VQFN-16), but pinouts differ across packages. Only the SOIC-16 variant uses the pin mapping shown in Figure 4-1 for D package. Substituting packages requires PCB layout revision due to distinct pin assignments, especially for NC, V_CC, and GND locations.