Diodes Incorporated PI3B3257QE

Overview

PI3B3257QE from Diodes Incorporated is a 3.3 V quad 2:1 multiplexer/demultiplexer with three-state outputs, pinout- and function-compatible with PI74FCT257T, 74F257, and 74ALS/AS/LS257 logic families. It features 5 Ω switch on-resistance, 4.8 ns max propagation delay, and ultra-low quiescent current (0.1 µA typical), enabling high-speed signal routing in notebook and portable computing systems.

For engineers reviewing the PI3B3257QE datasheet, PI3B3257QE pinout, PI3B3257QE application, or PI3B3257QE equivalent, key selection criteria include low on-resistance switching, rail-to-rail input tolerance up to +3.6 V, three-state output control via independent enable (E) and select (S), and compatibility with legacy 74-series logic footprints in QSOP packaging.

Technical Context

The PI3B3257QE implements four independent bidirectional analog/digital switches controlled by a shared select (S) and enable (E) signal. Each switch connects one of two inputs (IA0/IA1, IB0/IB1, etc.) to its corresponding output (YA–YD) with near-zero propagation delay and no ground bounce.

It operates as a transparent bus switch: when enabled and selected, signals pass through with only RC delay dominated by 5 Ω R_ON and load capacitance - not internal logic gates. Input logic levels are TTL-compatible and tolerate up to +3.6 V regardless of V_CC = 3.3 V ±10%.

Key Specifications

Pinout & Package

PI3B3257QE is supplied in a 16-pin QSOP (Q) package (150 mil width), with exposed pad not present. Pin 1 is marked by a notch or index area; GND (Pin 12) and V_CC (Pin 11) are adjacent to support low-inductance decoupling.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar quad 2:1 mux/demux applications.

Compared with SN74CBT3257PWR and 74LVC257PW,118, the PI3B3257QE delivers superior signal fidelity via lower on-resistance and faster switching, while its rail-to-rail input capability enables robust interoperability in heterogeneous voltage domains - critical for modern portable system integration.

Availability

PI3B3257QE is available at Aetrix Electronics and suitable for notebook computing, USB docking stations, and embedded test equipment requiring stable component supply, long-lifecycle support, and RoHS-compliant packaging.

Supply support for PI3B3257QE 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 consumer, computing, industrial, and communications markets.

The PI3B3257QE belongs to Diodes' NanoSwitch™ bus switch product line, engineered for ultra-low-power, high-speed signal routing in portable and space-constrained electronics where minimal propagation delay and leakage current are critical.

FAQ

Can PI3B3257QE operate with 5 V logic inputs while powered at 3.3 V?

Yes. The device accepts input voltages from –0.5 V to +4.6 V regardless of V_CC = 3.3 V, enabling direct interface with 5 V microcontrollers or FPGAs without level shifters. This rail-to-rail input tolerance is verified across –40°C to +85°C and specified in the DC Electrical Characteristics table.

What is the maximum continuous current per switch channel?

The absolute maximum DC output current is 120 mA per channel, as defined in the Maximum Ratings table. This rating applies under steady-state conditions with proper PCB thermal design; derating is recommended above +70°C ambient per the Power Dissipation specification (0.5 W max).

Is PI3B3257QE pin-compatible with standard 74-series 257 devices in SOIC packages?

Yes. The PI3B3257QE in QSOP (Q) matches the pinout and logic function of 74F257, 74ALS257, and 74AS257. Its SOIC variant (PI3B3257WEX) provides identical pin mapping and electrical behavior, allowing drop-in replacement on existing 16-pin SOIC footprints.

Does the PI3B3257QE require external pull-up or pull-down resistors on control pins?

No. The E and S inputs have CMOS-compatible thresholds and negligible leakage (±1 µA), so they can be driven directly from FPGA GPIO or microcontroller outputs. External biasing is unnecessary unless floating-state prevention is required in system-level power-down modes.