Diodes Incorporated PI5C3251Q

Overview

PI5C3251Q 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 over –40°C to +85°C ambient range for notebook and low-power embedded bus routing.

For engineers reviewing the PI5C3251Q datasheet, PI5C3251Q pinout, PI5C3251Q application, or PI5C3251Q equivalent, key selection criteria include its 5Ω analog switch performance, 16-pin QSOP package, E/S2–S0 select control interface, and compatibility with 5V TTL logic levels in high-speed data path isolation.

Technical Context

The PI5C3251Q implements two independent 8:1 analog multiplexers using low-R_ON NMOS pass-gate switches, enabling direct signal coupling without level-shifting or buffering. Each channel supports bidirectional operation and exhibits <6 pF input capacitance and 48 pF output capacitance when off.

Control logic uses active-low enable (E) and 3-bit binary select (S2–S0) to route one of eight inputs (I0–I7) to the shared output (Y). The device maintains high-impedance state when disabled, with ±1 µA leakage and –0.5 V to +7.0 V absolute maximum input/output voltage tolerance.

Key Specifications

Pinout & Package

PI5C3251Q is housed in a 16-pin, 150-mil wide QSOP (Quad Small Outline Package) with matte tin-plated leads, RoHS-compliant, halogen-free, and rated for reflow up to 260°C for 30 seconds.

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, PI5C3251Q uniquely delivers sub-nanosecond delay, 5Ω analog transparency, and 0.2 µA sleep current in a pin-compatible 5V legacy footprint-making it optimal for power-sensitive, high-fidelity bus switching where signal integrity is non-negotiable.

Availability

PI5C3251Q is available at Aetrix Electronics and suitable for notebook design, industrial PLC I/O consolidation, and legacy ISA bus upgrades requiring stable component supply and long-term obsolescence management.

Supply support for PI5C3251Q 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 semiconductor manufacturer specializing in discrete, analog, and mixed-signal ICs, with operations certified to IATF 16949 and ISO 9001 standards.

The PI5C3251Q belongs to Diodes' Pericom bus-switch product line, engineered specifically for low-distortion, low-power signal routing in portable computing and industrial control systems where pin compatibility with legacy logic is critical.

FAQ

Is PI5C3251Q compatible with 3.3V logic systems?

No - PI5C3251Q is specified for 5V ±5% operation only. Its input thresholds (VIH = 2.0 V, VIL = 0.8 V) and switch characteristics are optimized for 5V TTL/CMOS logic families. Using it with 3.3V signals risks undefined switching behavior and increased R_ON, as the internal NMOS gate drive relies on VCC = 5V for full enhancement.

Can PI5C3251Q be used for analog signal multiplexing?

Yes - it functions as a true analog switch with 5Ω R_ON, <6 pF C_IN, and rail-to-rail signal handling (–0.5 V to +7.0 V). It preserves signal integrity for DC-coupled analog signals up to ~100 MHz bandwidth, provided source impedance remains low (<100 Ω) to limit RC filtering effects.

What is the maximum continuous current rating per channel?

The absolute maximum DC output current is 120 mA, but sustained operation above 50 mA is discouraged due to thermal derating in the QSOP package. At 50 mA and 5Ω R_ON, power dissipation per switch is 12.5 mW - well within the 0.5 W total package limit, assuming ambient ≤+85°C and no adjacent high-power components.

Does PI5C3251Q support hot-swap or live-insertion?

It supports controlled hot-swap when enabled/disabled via E and S2–S0 with proper power sequencing: VCC must be stable before applying input signals, and E should be held LOW during insertion. The device lacks built-in current limiting or ESD protection beyond standard HBM (2 kV), so external series resistors and TVS diodes are recommended for field-replaceable interfaces.