Diodes Incorporated PI3B3126QEX-2017

Overview

PI3B3126QEX from Diodes Incorporated is a 3.3V, 4-bit, 2-port bus switch with individual active-HIGH enables, fabricated in sub-micron CMOS. It features four 5Ω analog switches, near-zero propagation delay (0.25ns), ultra-low quiescent current (0.1µA typical), and operates across –40°C to +85°C. It is used in notebook I/O routing where low power, fast switching, and signal integrity are critical.

For engineers reviewing the PI3B3126QEX datasheet, PI3B3126QEX pinout, PI3B3126QEX application, or PI3B3126QEX equivalent, key selection criteria include active-HIGH enable logic, 5Ω on-resistance, 4ns max switching speed, QSOP-16 package compatibility, and rail-to-rail input tolerance up to 3.6V independent of VCC.

Technical Context

The PI3B3126QEX implements four independent bidirectional analog bus switches, each controlled by a dedicated Bus Enable (BE0–BE3) input. When enabled, the A-side pin connects directly to the B-side pin with no added propagation delay beyond RC time constant (~0.25ns for 50pF load).

It uses advanced sub-micron CMOS process to achieve 5Ω typical R_ON, 1.0–2.5ns bus enable time, and supports hot-plug operation with rail-to-rail logic inputs (0–3.6V) regardless of 3.3V supply. Power-up sequencing requires VCC/GND applied before control or data signals.

Key Specifications

Pinout & Package

PI3B3126QEX is housed in a 16-pin QSOP (150mil wide) package with exposed pad not present; lead-free and halogen-free per RoHS 3 and Diodes' Green definition.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 4-bit bus switch applications.

Compared with PI3B3126LEX and SN74CBT3126PWR, the PI3B3126QEX offers the lowest quiescent current (0.1µA vs. ≥1µA), smallest package footprint among 4-bit switches with NC pins, and fastest enable timing (1.0–2.5ns), making it optimal for space-constrained, battery-sensitive notebook I/O architectures.

Availability

PI3B3126QEX is available at Aetrix Electronics and suitable for notebook I/O routing, LPC bus sharing, eSPI channel isolation, and wake-signal distribution requiring stable component supply across extended product lifecycles.

Supply support for PI3B3126QEX 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 PI3B series targets high-speed, low-power logic interface applications-specifically optimized for portable computing I/O expansion, where nanosecond timing, sub-microwatt standby, and robust mixed-voltage operation are essential.

FAQ

What is the maximum signal frequency supported by PI3B3126QEX?

The PI3B3126QEX does not specify a hard frequency limit but supports signals up to 66MHz (eSPI) and 480Mbps (USB 2.0) due to its 5Ω R_ON, 8pF COFF, and 0.25ns propagation delay. Bandwidth is governed by RC time constant (~0.25ns into 50pF), making it suitable for high-speed digital buses where edge integrity matters more than sinusoidal frequency response.

Can PI3B3126QEX operate with 2.5V or 1.8V logic inputs?

Yes-its logic inputs tolerate –0.5V to +3.6V regardless of VCC, so 1.8V or 2.5V control signals are fully compatible. However, VCC must remain at 3.3V ±10% to guarantee specified R_ON, timing, and leakage performance; lower VCC degrades R_ON and increases t_PZH.

Are the NC pins on PI3B3126QEX required to be left floating?

No-the NC pins (7 and 8) are internally unconnected and may be left floating, tied to GND, or tied to VCC without electrical impact. Diodes recommends leaving them unconnected unless PCB routing constraints require grounding for mechanical stability; no current flows through these pins under any condition.

How does PI3B3126QEX handle power sequencing during hot-plug events?

It supports hot-plug when inputs are driven within –0.5V to +3.6V before VCC is applied, but Diodes specifies proper sequencing: apply VCC and GND first, then logic signals. If inputs arrive early, the device enters high-impedance state until VCC stabilizes-no damage occurs, but undefined switching may result until supply settles within regulation.