Nexperia USA Inc. CBT3251D,118

Overview

CBT3251D,118 from Nexperia is a 1-of-8 FET bus switch configured as a single-pole, 8-throw multiplexer/demultiplexer with active-Low output enable (OE), three binary select inputs (S0–S2), 5 Ω typical ON resistance at 5 V, -40 °C to +85 °C operating range, and SO16 (SOT109-1) package. It routes one A port bidirectionally to any of eight B ports in high-speed digital signal path switching applications such as FPGA I/O expansion or memory address routing.

For engineers reviewing the CBT3251D,118 datasheet, CBT3251D,118 pinout, CBT3251D,118 application, or CBT3251D,118 equivalent, key selection considerations include its TTL-compatible control interface, overvoltage-tolerant inputs up to 5.5 V, IOFF partial power-down capability, sub-6 ns enable/disable timing, and guaranteed 128 mA per-switch current handling under 4.5–5.5 V supply.

Technical Context

The CBT3251D implements an NMOS-only transmission gate architecture with integrated level-shifting circuitry on control inputs, enabling direct interfacing with 3.3 V or 5 V TTL logic while maintaining overvoltage tolerance. Its IOFF feature ensures isolation between A and B ports when VCC = 0 V, preventing back-drive current leakage during system power sequencing.

Functionally, it operates as a digitally controlled analog switch: OE must be LOW to activate switching; S2:S1:S0 selects one of eight B terminals (B1–B8) to connect bidirectionally with the A terminal. Propagation delay is dominated by R_ON–C_io(off) time constant, with typical t_pd < 0.25 ns for A↔B paths and t_en/t_dis < 6.4 ns for OE-controlled transitions.

Key Specifications

Pinout & Package

CBT3251D,118 is housed in a plastic small outline package (SO16) per SOT109-1 standard: 16-pin, 3.9 mm body width, 1.27 mm lead pitch, gull-wing leads, JEDEC MS-012 compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74CBT3251PWR and 74LVC1G3157GW,125, the CBT3251D,118 uniquely combines integrated 3-bit decoding, lowest ICC, and IOFF in SO16-making it optimal for space-constrained industrial controllers needing reliable multi-channel routing without external glue logic.

Availability

CBT3251D,118 is available at Aetrix Electronics and suitable for PCI Express lane routing, FPGA I/O expansion, memory address decoding, and test access port switching requiring stable component supply across industrial temperature ranges and long-lifecycle programs.

Supply support for CBT3251D,118 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

Nexperia is a leading Dutch semiconductor manufacturer specializing in high-performance, high-reliability logic, analog, and discrete components for industrial, automotive, and computing markets.

The CBT3251 belongs to Nexperia's advanced bus switch product line, designed specifically for low-latency, high-fidelity digital signal routing in mixed-voltage systems where power sequencing, ESD robustness, and minimal propagation delay are critical.

FAQ

Can CBT3251D,118 operate with a 3.3 V supply?

No. The CBT3251D,118 requires VCC between 4.5 V and 5.5 V per its Recommended Operating Conditions. While its control inputs tolerate up to 5.5 V and interface directly with 3.3 V TTL logic levels (VIL ≤ 0.8 V, VIH ≥ 2.0 V), the internal FET switch core is not characterized or guaranteed below 4.5 V. Operation outside this range may result in elevated R_ON, timing violations, or undefined behavior.

What is the maximum continuous current per switch channel?

The absolute maximum continuous current per switch (A↔Bn) is 128 mA, as specified in the Limiting Values table. This rating applies under recommended operating conditions (VCC = 4.5–5.5 V, Tamb = -40 °C to +85 °C) and assumes proper PCB thermal design. Exceeding this current risks thermal runaway due to I²R heating in the 5 Ω ON resistance path.

Does CBT3251D,118 support bidirectional signal flow?

Yes. The CBT3251D,118 is a fully bidirectional analog switch: signals pass equally well from A to any selected Bn or from Bn to A. This is inherent to its FET transmission-gate topology and confirmed in the Functional Description (Table 3) and Pin Description (A and Bn pins labeled as "input/output" and "outputs/inputs", respectively). No direction control pin is required.

How does the IOFF feature behave when VCC is disconnected?

When VCC = 0 V, the IOFF circuitry actively disables all switch paths, ensuring leakage current between A and any Bn remains below ±1 μA-even if voltage is present on either side. This prevents back-powering of unpowered circuit sections and is validated per JEDEC JESD8-11. The feature operates independently of OE and select inputs, making it effective during power sequencing or fault conditions.