Texas Instruments SN74CBTLV3257DR

Overview

SN74CBTLV3257DR from Texas Instruments is a low-voltage 4-bit 1-of-2 FET multiplexer/demultiplexer in SOIC-16 package, featuring 5 Ω on-state resistance, rail-to-rail signal switching, and I_off partial-power-down protection. It routes bidirectional data between four common A ports and eight B-side channels (B1/B2 per channel) under control of active-low OE and single S select input, enabling dynamic bus sharing in high-speed digital interconnects.

For engineers reviewing the SN74CBTLV3257DR datasheet, SN74CBTLV3257DR pinout, SN74CBTLV3257DR application, or SN74CBTLV3257DR equivalent, key selection criteria include on-resistance stability across 2.3–3.6 V supply, sub-6 ns enable/disable timing, ±128 mA channel current rating, and JESD 78 Class II latch-up immunity - all critical for reliable signal routing in enterprise computing and wired networking backplanes.

Technical Context

The SN74CBTLV3257DR implements four independent analog/digital bidirectional switches, each with a single-pole double-throw (SPDT) topology controlled by one shared S input and global OE. Its FET-based architecture delivers rail-to-rail voltage transfer without level-shifting, supporting logic families from 1.8 V to 3.3 V systems while maintaining signal integrity up to 200 MHz.

Functional operation follows a strict truth table: when OE = L, S = L connects each A port to its corresponding B1 terminal; S = H connects to B2; OE = H forces all switches into high-impedance isolation. The I_off specification (≤15 µA at V_CC = 0 V) guarantees no backflow current during power sequencing, satisfying partial-power-down requirements in multi-rail systems.

Key Specifications

Pinout & Package

SN74CBTLV3257DR uses a 16-pin SOIC (D) package measuring 9.90 mm × 3.91 mm with standard 1.27 mm pitch. Pin 1 is S (Select), Pin 8 is GND, Pin 15 is OE (active-low Output Enable), and Pin 16 is V_CC. All 16 pins are surface-mount gull-wing leads compatible with IPC-7351B footprint D_300X100_16P.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74CBTLV3257PWR and SN74CBTLV3257DGVR, the SN74CBTLV3257DR offers the largest SOIC footprint for manual assembly and thermal mass, making it suitable for prototyping and thermally stable industrial control boards where layout flexibility is prioritized over miniaturization.

Availability

SN74CBTLV3257DR is available at Aetrix Electronics and suitable for datacenter interconnects, industrial Ethernet switching, and building automation systems requiring stable component supply across extended product lifecycles.

Supply support for SN74CBTLV3257DR 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 and embedded processing technologies, with decades of expertise in high-speed interface solutions.

The SN74CBTLV3257DR belongs to TI's CBTLV low-voltage FET switch family, designed specifically for low-latency, low-distortion signal routing in enterprise computing, wired networking, and industrial communications infrastructure.

FAQ

What is the maximum operating frequency supported by the SN74CBTLV3257DR?

The SN74CBTLV3257DR is characterized for operation up to 200 MHz, verified through switching specifications and typical application curves. This maximum frequency assumes optimal PCB layout (controlled impedance, minimized trace capacitance) and load conditions within the ±128 mA channel current limit. Signal integrity at this rate relies on the device's 5 Ω on-resistance and sub-0.25 ns A↔B propagation delay, as documented in Section 5.7 of the SN74CBTLV3257DR datasheet.

Does the SN74CBTLV3257DR require external pull-up resistors on the OE pin?

Yes, the SN74CBTLV3257DR requires a pull-up resistor on the OE pin to V_CC to ensure a defined high-impedance state during power-up and power-down sequences. The minimum resistor value depends on the current-sinking capability of the driving source, but a standard 10 kΩ resistor is commonly used. This requirement is explicitly stated in the SN74CBTLV3257DR functional description to prevent undefined switching behavior when V_CC is not yet stable.

Can the SN74CBTLV3257DR interface between 1.8 V and 3.3 V logic domains?

No, the SN74CBTLV3257DR does not perform voltage translation. It operates from a single 2.3–3.6 V supply and supports rail-to-rail signal switching only within that supply range. While its I/O pins tolerate up to 4.6 V, the output swing is always bounded by V_CC and GND. To interface 1.8 V and 3.3 V domains, a dedicated level translator such as the TXB0108 must be used upstream or downstream of the SN74CBTLV3257DR.

What is the thermal resistance (R_θJA) of the SN74CBTLV3257DR in its SOIC package?

According to the SN74CBTLV3257DR datasheet Section 5.3, the junction-to-ambient thermal resistance (R_θJA) for the SOIC (D) package is 102.5 °C/W under standard JEDEC test conditions. This value assumes a 2-layer PCB with 1 in² copper pour connected to the package leads. Actual thermal performance in end equipment will vary based on board layout, copper area, airflow, and adjacent heat sources.

Is the SN74CBTLV3257DR pin-compatible with other members of the SN74CBTLV3257 family?

Yes, all SN74CBTLV3257 variants - including SN74CBTLV3257DR (SOIC), SN74CBTLV3257PWR (TSSOP), and SN74CBTLV3257DGVR (TVSOP) - share identical pin functions and electrical specifications. The pin numbering and signal mapping (e.g., Pin 1 = S, Pin 15 = OE, Pin 16 = V_CC) are consistent across packages, enabling direct PCB footprint substitution where mechanical constraints allow.