Diodes Incorporated PI3B3257WE

Overview

PI3B3257WE from Diodes Incorporated is a 3.3 V quad 2:1 multiplexer/demultiplexer with three-state outputs, pinout- and function-compatible with 74F257, 74ALS257, and PI74FCT257T. It features 5 Ω switch on-resistance, 4.8 ns max propagation delay, and 0.1 µA typical quiescent current, enabling low-noise signal routing in notebook and portable logic systems.

For engineers reviewing the PI3B3257WE datasheet, PI3B3257WE pinout, PI3B3257WE application, or PI3B3257WE equivalent, key selection criteria include guaranteed 3.3 V operation, rail-to-rail logic input tolerance up to +3.6 V, ultra-low ICC, and compatibility with legacy 74-series bus-switch footprints across QSOP, SOIC, TSSOP, and UQFN packages.

Technical Context

The PI3B3257WE implements four independent bidirectional analog/digital switches controlled by a shared select (S) and enable (E) line. Each switch exhibits near-zero propagation delay due to its low R_ON–C_OFF time constant (~0.25 ns for 50 pF load), and operates without ground bounce noise under full 120 mA output drive capability.

It supports hot-plug operation with rail-to-rail input voltage tolerance (–0.5 V to +3.6 V), independent of V_CC, and maintains high-impedance outputs when disabled. The device uses CMOS process technology optimized for low static power and fast switching in battery-sensitive applications.

Key Specifications

Pinout & Package

PI3B3257WE is available in 16-pin SOIC (W) package (5.3 mm × 10.2 mm, 1.27 mm pitch). Pin functions are identical across all package variants (QSOP, TSSOP, UQFN).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar quad 2:1 bus switch applications.

Compared with SN74CBT3257PWR and PI3CH4816LEX, PI3B3257WE uniquely combines bidirectional operation, rail-to-rail input tolerance, and lowest R_ON in a pin-compatible 74-series footprint-making it optimal for portable, mixed-voltage, and high-fidelity analog/digital switching.

Availability

PI3B3257WE is available at Aetrix Electronics and suitable for USB 2.0 switching, laptop display interface routing, and PCIe lane sharing requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant packaging.

Supply support for PI3B3257WE 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

Diodes Incorporated is a global manufacturer of discrete semiconductors and integrated circuits, specializing in high-performance, energy-efficient components for computing, consumer, industrial, and communications markets.

The PI3B3257 belongs to Diodes' NanoSwitch™ family of low-R_ON, low-power analog switches designed specifically for high-speed signal routing in portable and space-constrained electronics.

FAQ

Can PI3B3257WE operate with 2.5 V or 1.8 V logic inputs?

Yes. Its logic control inputs (S and E) accept –0.5 V to +3.6 V regardless of V_CC, enabling direct interface with 2.5 V or 1.8 V drivers without level shifters. However, analog/digital signal switching remains constrained to the 0–V_CC range (0–3.3 V), so input signals outside this band may clamp or distort.

Is PI3B3257WE suitable for USB 3.0 or PCIe Gen2 applications?

No. With a maximum bandwidth limited by its 5 Ω R_ON and ~17 pF Y_N capacitance, PI3B3257WE supports signal integrity up to ~100 MHz - sufficient for USB 2.0 (480 Mbps) and PCIe Gen1 (2.5 Gbps), but not USB 3.0 (5 Gbps) or PCIe Gen2 (5 Gbps), which require sub-1 Ω R_ON and <5 pF capacitance.

What is the thermal pad requirement for the ZHD (UQFN) package?

The ZHD package requires soldering the exposed center thermal pad to a dedicated PCB copper area with ≥4 thermal vias (0.3 mm diameter, spaced ≤1 mm apart) connecting to internal ground planes. Failure to connect the pad to GND compromises thermal dissipation, electrical stability, and ESD performance - the device will not meet its 0.5 W power rating or 85°C ambient specification.

Does PI3B3257WE support hot-swap insertion while powered?

Yes, when proper sequencing is followed: V_CC and GND must be applied before any signal or control voltage. The rail-to-rail input tolerance and high-impedance disable state allow safe insertion into live backplanes or docking connectors, provided E is held high until power stabilizes and control signals settle - preventing glitch-induced latch-up or transient current surges.