Diodes Incorporated PI3CH400LEX

Overview

PI3CH400LEX from Diodes Incorporated is a 4-bit, low-voltage bus switch with active-low enables, designed for high-bandwidth signal routing in hot-plug interfaces. It operates at 1.8V/2.5V/3.3V supply voltages, delivers 500 MHz bandwidth, exhibits near-zero propagation delay (≤0.3 ns), and supports rail-to-rail analog switching (0–5V with 3.3V V_CC). It is used in PCIe Gen1/2 data path isolation and backplane hot-docking circuits.

For engineers reviewing the PI3CH400LEX datasheet, PI3CH400LEX pinout, PI3CH400LEX application, or PI3CH400LEX equivalent, key selection criteria include enable polarity (active-low), on-resistance (4–8 Ω across supply ranges), I/O tolerance (5V tolerant in ON/OFF states), and package-specific thermal performance (TSSOP-14 vs. QFN-14).

Technical Context

The PI3CH400LEX implements four independent single-pole single-throw (SPST) NMOS transmission gates with individual active-low enable inputs (EN0–EN2). Each channel connects A_x to B_x with no added ground bounce or logic-level translation-only passive resistive-capacitive signal path behavior.

Its architecture enables simultaneous or staggered channel control for dynamic bus segmentation, supporting differential pair routing (e.g., USB 2.0 D+/D−) and high-speed parallel data buses. The device maintains signal integrity via low on-capacitance (7.0 pF ON, 3.5 pF OFF) and high off-isolation (–60 dB at 10 MHz).

Key Specifications

Pinout & Package

PI3CH400LEX is supplied in a Pb-free, RoHS-compliant 14-pin TSSOP (L) package (4.4 mm × 5.0 mm, 0.65 mm pitch), optimized for thermal dissipation and reflow compatibility in high-density layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74CBT3245APWR and MAX4617ESE+, PI3CH400LEX provides unique 1.8V operation, active-low enables, 5V I/O tolerance, and integrated 4-channel routing-reducing BOM count and simplifying enable sequencing in hot-plug systems.

Availability

PI3CH400LEX is available at Aetrix Electronics and suitable for PCIe slot isolation, USB 2.0 hot-dock interfaces, and FPGA I/O expansion requiring stable component supply across industrial temperature ranges and long-lifecycle programs.

Supply support for PI3CH400LEX 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, specializing in high-performance, energy-efficient solutions for industrial, computing, and communications markets.

The PI3CH400LEX belongs to Diodes' Pericom® high-speed interface portfolio, engineered specifically for signal integrity-critical hot-plug and bus-switching applications in datacom infrastructure and embedded systems.

FAQ

What is the maximum allowable voltage on A/B pins when V_CC = 0V?

The PI3CH400LEX guarantees 5V I/O tolerance on all A_x and B_x pins-even with V_CC unpowered. This allows safe hot-insertion into live backplanes where supply sequencing is uncontrolled. The internal ESD protection diodes clamp transients up to ±6V for ≤20 ns without latch-up or damage, per JESD17 testing.

Can PI3CH400LEX switch differential signals like LVDS or RGMII without degradation?

Yes-its 7.0 pF ON-state capacitance, 500 MHz bandwidth, and matched A_x/B_x channel characteristics preserve differential pair integrity. Measured crosstalk is –60 dB at 10 MHz, and propagation delay skew between channels is <0.1 ns, making it suitable for RGMII (1.25 Gbps) and LVDS (800 Mbps) routing where common-mode rejection and timing alignment are critical.

How does the "beyond rail-to-rail" specification work with 3.3V V_CC?

With V_CC = 3.3V, the PI3CH400LEX passes analog signals from 0V to 5V across A_x–B_x terminals. This is achieved through optimized NMOS gate drive and body biasing that prevents channel pinch-off beyond V_CC. It enables direct interfacing between 3.3V SoCs and 5V legacy peripherals-no external level shifters needed-while maintaining <8 Ω on-resistance across the full 0–5V range.

Is PI3CH400LEX pin-compatible with PI3CH400ZBEX?

No-PI3CH400LEX (TSSOP-14) and PI3CH400ZBEX (QFN-14) share identical electrical functionality and pin numbering but differ in mechanical layout, thermal pad configuration, and solder-reflow profile. The QFN variant has an exposed thermal pad (pin 15) and 0.5 mm pitch, while TSSOP uses 0.65 mm pitch and no thermal pad. PCB layout and stencil design must be revised for package substitution.