Diodes Incorporated PI3C3126Q

Overview

PI3C3126Q from Diodes Incorporated is a 4-bit, 2-port bus switch IC with individual active-HIGH enables, designed for high-bandwidth signal routing in 2.5V/3.3V systems. It features 5-Ω ON-resistance, <0.25 ns propagation delay, 400+ MHz bandwidth, 5V I/O tolerance, and rail-to-rail switching-enabling hot insertion in PCIe, USB, and memory interface applications.

For engineers reviewing the PI3C3126Q datasheet, PI3C3126Q pinout, PI3C3126Q application, or PI3C3126Q equivalent, key selection criteria include per-channel enable control, sub-nanosecond enable/disable timing (tPZH/tPHZ ≤ 6.5 ns), 5V-tolerant I/O under 3.3V supply, and dual-package availability (14-pin TSSOP L14 / 16-pin QSOP Q16).

Technical Context

The PI3C3126Q implements four independent analog bus switches, each with dedicated BE_n control enabling/disabling A_n–B_n conduction without logic inversion. Its MOSFET-based switch architecture delivers rail-to-rail analog pass-through with no DC offset or level-shifting.

Switching behavior is defined by three-state operation: when BE_n = LOW, A_n/B_n present high-impedance isolation (R_OFF > 1 GΩ); when BE_n = HIGH, A_n and B_n are bidirectionally connected via a low-R_ON (5 Ω typ.) path, supporting AC-coupled and DC-coupled signals up to 400 MHz.

Key Specifications

Pinout & Package

PI3C3126Q is supplied in a 16-pin QSOP (Q16) package, 150-mil wide, Pb-free and RoHS-compliant. Pin count and layout match industry-standard 74xx126 logic but implement analog switch functionality instead of buffer logic.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74CBT3126PW and PI3CH4816Q, PI3C3126Q uniquely balances 5V I/O tolerance, per-channel enables, and 5 Ω R_ON in a compact 16-pin QSOP-making it optimal for mixed-voltage hot-plug systems where channel independence and signal fidelity are prioritized over channel count or absolute lowest R_ON.

Availability

PI3C3126Q is available at Aetrix Electronics and suitable for PCIe Gen1/2 switching, USB 2.0 hub multiplexing, and DDR memory bus isolation requiring stable component supply across industrial and computing platforms.

Supply support for PI3C3126Q 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 analog, logic, and power management solutions for computing, industrial, and consumer markets.

The PI3C3126Q belongs to Diodes' Pericom product line, engineered specifically for high-fidelity, low-latency signal routing in mixed-voltage, hot-pluggable digital interfaces such as PCIe, USB, and memory subsystems.

FAQ

What is the maximum operating frequency supported by PI3C3126Q?

The PI3C3126Q supports signal bandwidth exceeding 400 MHz, validated by its 5 Ω R_ON and 10 pF C_ON resulting in an RC time constant of ~0.05 ns-well below the rise time of 2 Gbps NRZ signals. This enables reliable use in PCIe Gen1 (2.5 GT/s) and USB 2.0 (480 Mbps) applications without equalization.

Can PI3C3126Q operate with 2.5V and 3.3V supplies simultaneously?

No-PI3C3126Q uses a single VCC pin and must be powered from either 2.5V or 3.3V (±10%). However, its 5V-tolerant I/O allows interfacing with higher-voltage peripherals regardless of VCC setting, eliminating need for external level shifters in mixed-voltage systems.

Is PI3C3126Q pin-compatible with standard 74-series logic devices?

Yes-its 16-pin QSOP (Q16) pinout matches the industry-standard 74xx126 buffer layout, enabling drop-in replacement in existing PCB footprints. However, function differs: PI3C3126Q provides analog bidirectional switching, not logic buffering, so signal integrity and termination must be re-verified.

Does PI3C3126Q require external pull-up or pull-down resistors on enable pins?

No-BE_n inputs have CMOS-compatible thresholds (VIH ≥ 2.0 V, VIL ≤ 0.8 V) and leakage < ±1 µA, allowing direct connection to FPGA GPIO or microcontroller outputs. External resistors are unnecessary unless system-level noise immunity or default-safe state (e.g., disabled at power-up) is required.