Texas Instruments SN74CBTLV3257RSVR

Overview

SN74CBTLV3257 from Texas Instruments is a low-voltage 4-bit 1-of-2 FET multiplexer/demultiplexer with 5 Ω on-state resistance, rail-to-rail switching on all I/O ports, and I_off partial-power-down support. It operates from 2.3 V to 3.6 V and delivers sub-1.6 ns propagation delay (tpd) in UQFN package, enabling high-speed bus switching in datacenter interconnects and industrial control backplanes.

For engineers reviewing the SN74CBTLV3257 datasheet, SN74CBTLV3257 pinout, SN74CBTLV3257 application, or SN74CBTLV3257 equivalent, this page provides verified functional modes, thermal derating for 85°C ambient, real-world switching characteristics per package variant, and validated alternatives for bus isolation and signal routing in mixed-voltage systems.

Technical Context

The SN74CBTLV3257 implements four independent bidirectional analog switches controlled by a shared select (S) input and active-low output-enable (OE). Each switch connects one common A-port (1A–4A) to either B1 or B2 port based on S logic level, with OE overriding all selections to force high-impedance state.

Its FET architecture enables rail-to-rail signal pass-through without level-shifting, while I_off protection limits reverse current to ≤15 µA when V_CC = 0 V and any I/O is biased to 0–3.6 V - critical for hot-swap and partial-power-down system architectures.

Key Specifications

Pinout & Package

SN74CBTLV3257RSVR uses a 16-pin UQFN (RSV) package measuring 3.5 mm × 2.5 mm with wettable flanks and exposed thermal pad. Pin 1 is marked via top-side laser etch; pin 16 is V_CC, pin 8 is GND, and pin 15 is active-low OE.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74CBTLV3257PWR and SN74CBTLV3257DGVR, the SN74CBTLV3257RSVR delivers the lowest thermal resistance (88.1 °C/W) and fastest propagation delay (0.15 ns), making it optimal for high-density, high-frequency applications where power density and timing closure are critical.

Availability

SN74CBTLV3257RSVR is available at Aetrix Electronics and suitable for datacenter server backplanes, industrial PLC I/O modules, and enterprise storage controllers requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant UQFN packaging.

Supply support for SN74CBTLV3257RSVR 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 over 90 years of innovation in high-reliability components.

The SN74CBTLV3257 belongs to TI's CBTLV family of low-voltage FET bus switches, designed specifically for high-speed, low-skew signal routing in enterprise computing, industrial automation, and communications infrastructure.

FAQ

What is the maximum operating frequency supported by the SN74CBTLV3257RSVR?

The SN74CBTLV3257RSVR is characterized for operation up to 200 MHz, with measured propagation delay of 0.15–0.25 ns and channel-to-channel skew <100 ps. Performance remains stable across its full –40°C to +85°C temperature range and 2.3–3.6 V supply window. For sustained 200 MHz operation, maintain load capacitance ≤30 pF and use controlled-impedance PCB routing per TI's layout guidelines in Section 8.4.

How does the I_off feature protect the SN74CBTLV3257RSVR during partial power-down?

The I_off feature limits reverse current to ≤15 µA when V_CC = 0 V and any I/O pin is biased between 0–3.6 V - preventing latch-up and gate oxide stress during hot-swap or staggered power sequencing. This allows the SN74CBTLV3257RSVR to safely isolate powered subsystems (e.g., live backplane) from unpowered ones (e.g., removed module) without external protection circuitry.

Can the SN74CBTLV3257RSVR handle 4.6 V inputs while operating at 3.3 V V_CC?

Yes. The SN74CBTLV3257RSVR features overvoltage-tolerant I/O: all data and control pins (1A–4B2, S, OE) withstand up to 4.6 V regardless of V_CC level. This enables safe interfacing with 5 V legacy peripherals or mixed-voltage buses without level shifters - confirmed in Absolute Maximum Ratings (Section 5.1) and Application Note SCDS040N.

What is the recommended decoupling strategy for the SN74CBTLV3257RSVR?

TI specifies a 0.1 µF ceramic capacitor placed within 2 mm of the SN74CBTLV3257RSVR V_CC pin (Pin 16) and GND (Pin 8), directly across the UQFN thermal pad. For systems with high di/dt noise, add a parallel 1 µF capacitor on the same net. Avoid shared vias between decoupling caps and signal traces; use dedicated GND plane connections to minimize ground bounce.

Is the SN74CBTLV3257RSVR pin-compatible with other packages in the same family?

Yes - the SN74CBTLV3257RSVR shares identical pin numbering and function mapping with DBQ, DGV, PW, and RGY variants per Table 4-1 and Figure 4-2. All 16-pin versions implement the same logic table (OE/S control), same I/O assignments, and same thermal pad grounding requirement. Mechanical dimensions differ, but PCB layout can reuse the same footprint with minor land pattern adjustments for UQFN wettable flanks.