Diodes Incorporated PI5C3251QE

Overview

PI5C3251QE from Diodes Incorporated is an 8:1 analog 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. Used in high-speed data routing for notebook and portable computing systems.

For engineers reviewing the PI5C3251QE datasheet, PI5C3251QE pinout, PI5C3251QE application, or PI5C3251QE equivalent, key selection criteria include on-resistance matching, enable-controlled three-state output behavior, TTL-compatible select logic, and QSOP-16 packaging for space-constrained PCB layouts.

Technical Context

The PI5C3251QE implements a single-pole, eight-throw (SP8T) analog switch architecture using NMOS pass transistors with integrated level-shifting control circuitry. Its three-state output enables bus isolation when disabled (E = HIGH), eliminating contention in shared-data-path systems.

All eight inputs (I0–I7) connect directly to the common output Y via low-R_ON switches under control of S2:S0 address bits and active-low enable E. No internal logic gates or latches are present - signal path is purely resistive with no added propagation delay beyond RC time constant.

Key Specifications

Pinout & Package

Package: 16-pin QSOP (150-mil wide), surface-mount, lead-free and RoHS-compliant per Diodes Incorporated 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 74LVC1G3157GW, the PI5C3251QE uniquely balances ultra-low power, single-package 8:1 functionality, and proven pin compatibility with legacy logic families - making it optimal for cost-sensitive, space-constrained, and battery-aware designs requiring direct replacement capability.

Availability

PI5C3251QE is available at Aetrix Electronics and suitable for notebook system design, industrial PLC I/O consolidation, and automated test equipment requiring stable component supply and long-term manufacturability.

Supply support for PI5C3251QE 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 analog ICs, headquartered in Plano, Texas, with design and manufacturing operations across Asia and the Americas.

The PI5C3251QE belongs to Diodes' Pericom-branded high-speed analog switch product line, engineered specifically for low-latency, low-power data path management in portable computing and industrial control systems.

FAQ

What is the maximum signal voltage that can be routed through the PI5C3251QE?

The PI5C3251QE supports signal voltages from –0.5V to V_CC + 0.5V, with absolute maximum ratings up to –0.5V to +7.0V on all I/O pins. For reliable operation at 5V supply, signals must remain within 0V to 5V; exceeding V_CC risks latch-up or permanent damage. Input clamping diodes activate at –0.7V and +5.7V (typical), but sustained operation outside the recommended range is not guaranteed.

Does the PI5C3251QE require external pull-up or pull-down resistors on its control pins?

No external biasing is required. The S2:S0 and E inputs have TTL-compatible thresholds (V_IL ≤ 0.8V, V_IH ≥ 2.0V) and exhibit low input leakage (±1 µA). Driving directly from standard CMOS or TTL outputs ensures reliable logic levels without additional components. Pull resistors may be used only for fail-safe default states during power-up or reset sequences.

Can the PI5C3251QE be used bidirectionally between any Ix pin and Y?

Yes - the PI5C3251QE is fully bidirectional. Signal flow direction (I_x → Y or Y → I_x) depends solely on voltage potential and external circuitry; the internal switch has no polarity. This enables flexible use in both multiplexer (multiple inputs to one output) and demultiplexer (one input to multiple outputs) configurations, provided only one path is enabled at a time.

How does the PI5C3251QE handle simultaneous switching of multiple channels?

The PI5C3251QE is a single-output device - only one I_x can be connected to Y at any time. Simultaneous switching of multiple channels is not supported. To route multiple independent signals, separate PI5C3251QE units or a higher-channel-count device (e.g., dual 4:1 or octal 2:1) must be used. Charge injection and glitch energy are minimized per channel due to optimized gate drive and layout.