Diodes Incorporated PI3B3251Q

Overview

PI3B3251Q from Diodes Incorporated is a 3.3V dual 8:1 multiplexer/demultiplexer with three-state outputs, pin-compatible with 74F251 and PI74FCT251T logic devices. It features 5Ω on-resistance, near-zero propagation delay (0.25 ns), ultra-low quiescent current (0.1 µA typical), and operates across –40°C to +85°C ambient. Used in notebook I/O routing and high-speed data path selection.

For engineers reviewing the PI3B3251Q datasheet, PI3B3251Q pinout, PI3B3251Q application, or PI3B3251Q equivalent, key selection criteria include low on-resistance switching, rail-to-rail logic input tolerance up to +3.6V, TSSOP-16 package compatibility, and sub-1ns signal path delay in 3.3V systems.

Technical Context

The PI3B3251Q implements dual independent 8:1 analog/digital bus switches using CMOS transmission-gate architecture. Each channel selects one of eight inputs (I0–I7) to Y output under 3-bit binary control (S0–S2), with active-low enable (E) enabling three-state output isolation.

It supports rail-to-rail logic inputs regardless of VCC (up to +3.6V), eliminates ground bounce via zero-threshold switching, and contributes negligible RC delay-typical tPD of 0.25 ns into 50 pF load-making it suitable for high-fidelity signal routing without timing skew.

Key Specifications

Pinout & Package

Package: 16-pin TSSOP (173-mil wide), RoHS-compliant, lead-free, green construction.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74CBT3251PWR and PI74FCT251TQ, the PI3B3251Q delivers superior low-power performance and faster switching in 3.3V systems, while maintaining full pin and functional compatibility with legacy 74-series logic-making it optimal for new designs and energy-sensitive upgrades.

Availability

PI3B3251Q is available at Aetrix Electronics and suitable for high-speed notebook I/O routing, legacy logic interface emulation, and low-power sensor hub multiplexing requiring stable component supply and long-term manufacturing continuity.

Supply support for PI3B3251Q 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 computing, consumer, industrial, and automotive markets.

The PI3B3251Q belongs to Diodes' NanoSwitch™ bus switch product line, designed specifically for low-latency, low-power signal routing in portable and space-constrained 3.3V digital systems.

FAQ

What is the maximum input voltage the PI3B3251Q logic pins can tolerate?

The PI3B3251Q logic inputs (S0–S2, E, I0–I7) tolerate voltages from –0.5V to +4.6V regardless of VCC, and specifically support rail-to-rail driving up to +3.6V even when VCC = 3.3V. This eliminates level-shifting requirements when interfacing with mixed-voltage controllers or legacy 5V-tolerant drivers.

Does the PI3B3251Q support hot-plug operation?

Yes-the PI3B3251Q supports controlled hot-plug operation when proper power sequencing is followed: apply VCC and GND before any signal or control inputs. Its three-state output and low leakage (<1 µA) prevent bus contention and back-driving during live insertion, provided the enable (E) pin is held inactive until power stabilization.

Is the NC pin (Pin 6) required to be grounded or left floating?

Pin 6 is a true no-connect with no internal bond wire or circuit connection. It must remain unconnected-neither grounded nor tied to VCC-to avoid introducing parasitic capacitance or unintended coupling that could degrade high-frequency signal integrity or increase crosstalk in adjacent channels.

How does the PI3B3251Q's on-resistance affect analog signal accuracy?

With a typical RON of 5 Ω and maximum of 8 Ω, the PI3B3251Q introduces negligible voltage drop (<40 mV at 8 mA) and maintains THD < –90 dB in audio paths. Its flat RON vs. input voltage curve ensures consistent gain and linearity across the full 0–3.3V signal range, making it suitable for precision analog multiplexing up to 10 MHz.