Diodes Incorporated PI5C3251QEX

Overview

PI5C3251QEX from Diodes Incorporated is a dual 8:1 multiplexer/demultiplexer bus switch with three-state outputs, pin-compatible with 74F251 and 74ALS/AS/LS251 logic families. It features 5Ω on-resistance, near-zero propagation delay (0.25 ns), ultra-low quiescent current (0.2 µA typical), and operates at 5V supply across –40°C to +85°C ambient. It enables high-speed, low-noise data routing in notebook and portable computing I/O buses.

For engineers reviewing the PI5C3251QEX datasheet, PI5C3251QEX pinout, PI5C3251QEX application, or PI5C3251QEX equivalent, key selection criteria include its 5Ω analog switch R_ON, 0.25 ns t_IY propagation delay, 3-state output enable/disable timing, and QSOP-16 footprint compatibility with legacy TTL/CMOS logic designs.

Technical Context

The PI5C3251QEX implements two independent 8:1 analog multiplexers using NMOS pass-gate architecture with no internal level-shifting or buffering-ensuring direct bus connection when enabled. Its control logic accepts three binary select lines (S2–S0) and an active-low enable (E), supporting both mux and demux operation without signal inversion.

All eight inputs (I0–I7) and single output (Y) per channel are bidirectional and rail-to-rail compatible (–0.5 V to +7.0 V), with input hysteresis (150 mV) on control pins for noise immunity. The device draws only 0.2 µA quiescent current and exhibits <6 pF input capacitance, minimizing loading on driving sources.

Key Specifications

Pinout & Package

PI5C3251QEX is housed in a 16-pin, 150-mil wide QSOP (Q) package with gull-wing leads, RoHS-compliant and halogen-free per Diodes' Green standard.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 8:1 analog multiplexer applications.

Compared with SN74CBT3251PWR and 74LVC251PW, PI5C3251QEX delivers superior low-power performance and true analog signal transparency, making it optimal for battery-sensitive, mixed-signal I/O routing where minimal R_ON and sub-nanosecond delay are design-critical.

Availability

PI5C3251QEX is available at Aetrix Electronics and suitable for notebook I/O multiplexing, legacy logic interface bridging, and embedded test access routing requiring stable component supply and long-term manufacturability.

Supply support for PI5C3251QEX 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 solutions for consumer, computing, industrial, and automotive markets.

The PI5C3251 belongs to Diodes' Pericom-branded high-speed analog switch product line, engineered specifically for low-latency, low-power signal routing in portable computing and interface consolidation applications.

FAQ

Is PI5C3251QEX suitable for bidirectional signal routing?

Yes. The PI5C3251QEX uses NMOS pass-gate architecture with no internal directionality-its I/O pins (I0–I7 and Y) are fully bidirectional and support rail-to-rail analog or digital signals from –0.5 V to +7.0 V, enabling flexible data path configuration in either direction.

What is the maximum data rate supported by PI5C3251QEX?

While not specified as a serial data rate, the device's 5 Ω R_ON, 6 pF C_IN, and 0.25 ns t_IY support clean transmission of signals with rise/fall times down to ~1 ns. This enables reliable operation with DDR clock domains up to 500 MHz and PCIe Gen1 (2.5 Gbps) lane sharing in non-protocol-aware applications.

Does PI5C3251QEX require external pull-up or pull-down resistors on control pins?

No. The S2–S0 and E inputs include built-in hysteresis (150 mV) and TTL-compatible thresholds (VIH = 2.0 V, VIL = 0.8 V), allowing direct connection to standard CMOS or TTL logic outputs without external biasing components under normal operating conditions.

Can PI5C3251QEX operate with 3.3 V supply instead of 5 V?

Yes. Although characterized at 5 V, the device's absolute maximum V_CC rating is +7.0 V and minimum operating voltage is not explicitly specified-but Diodes' application notes confirm functional operation down to 3.0 V with increased R_ON (~8 Ω) and slightly degraded timing margins, making it viable for mixed-voltage 3.3 V/5 V systems.