Diodes Incorporated PI3B3257QEX

Overview

PI3B3257QEX 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, deployed in high-speed data routing for notebook and embedded logic systems.

For engineers reviewing the PI3B3257QEX datasheet, PI3B3257QEX pinout, PI3B3257QEX application, or PI3B3257QEX 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, and compatibility with legacy 74-series logic footprints in QSOP packaging.

Technical Context

The PI3B3257QEX implements four independent bidirectional analog/digital bus switches, each controlled by a shared select (S) and global enable (E) signal. Each switch exhibits near-zero propagation delay (<0.25 ns intrinsic RC delay) and operates without ground bounce due to its low-impedance CMOS transmission gate architecture.

It supports hot-plug operation with rail-to-rail logic inputs (0–3.6 V), independent of V_CC = 3.3 V ±10%, and maintains high-impedance outputs when disabled. The device draws only 0.1 µA quiescent current, making it suitable for battery-sensitive portable applications.

Key Specifications

Pinout & Package

PI3B3257QEX is housed in a 16-pin QSOP (150-mil width) package with exposed pad not present; all pins are surface-mount gull-wing leads. Pin 1 is marked by a notch or dot, and the package complies with RoHS 3 and Diodes Incorporated's Green standard.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74CBT3257PWR and PI74FCT257TQX, the PI3B3257QEX delivers superior low-power operation and broader input voltage tolerance while maintaining identical footprint and functional behavior-making it optimal for next-generation portable and energy-conscious industrial logic interfaces.

Availability

PI3B3257QEX is available at Aetrix Electronics and suitable for notebook computing, industrial PLC I/O expansion, and automated test equipment requiring stable component supply and long-term lifecycle assurance.

Supply support for PI3B3257QEX 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 ICs, specializing in high-performance, energy-efficient solutions for consumer, industrial, and communications markets.

The PI3B3257 belongs to Diodes' NanoSwitch™ bus switch product line, engineered for low-latency, low-power signal routing in space-constrained portable and embedded systems where legacy logic compatibility and thermal efficiency are critical.

FAQ

Can PI3B3257QEX operate with 2.5 V or 5 V supply?

No. The PI3B3257QEX is specified only for 3.3 V ±10% operation (2.97–3.63 V). Its internal circuitry, including switch threshold and drive strength, is optimized for this range. Operation outside this window may cause undefined logic states, increased R_ON, or reliability degradation. It does support rail-to-rail inputs up to +3.6 V, but V_CC itself must remain within spec.

Is the QSOP package lead-free and RoHS-compliant?

Yes. The "E" suffix in PI3B3257QEX denotes Diodes Incorporated's Pb-free and Green-compliant construction, meeting EU Directive 2015/863/EU (RoHS 3). The package uses matte tin plating and halogen-free molding compound, verified per Diodes' quality documentation PD-2209 and packaging compliance reports.

What is the maximum capacitive load the PI3B3257QEX can drive reliably?

The device is characterized for CL = 50 pF in switching tests, with t_IY = 0.25 ns typ. At higher loads (e.g., >100 pF), propagation delay increases linearly with RC time constant (R_ON × C_L). For reliable operation beyond 50 pF, ensure driving source has adequate slew rate and verify setup/hold timing margins in the target application.

Does PI3B3257QEX support hot-swap insertion while powered?

Yes-when used per Diodes' recommended sequencing: apply V_CC and GND before any signal or control inputs. Its rail-to-rail input tolerance (–0.5 V to +4.6 V) and absence of input clamping current above V_CC allow safe hot-plug operation in backplane or modular systems, provided E and S are held inactive (E = HIGH) during insertion.