Diodes Incorporated PI3B3125QEX

Overview

PI3B3125QEX from Diodes Incorporated is a 3.3V, 4-bit, 2-port bus switch with individual active-low enables, fabricated in advanced 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 expansion and low-power signal routing where rail-to-rail logic compatibility and minimal ground bounce are critical.

For engineers reviewing the PI3B3125QEX datasheet, PI3B3125QEX pinout, PI3B3125QEX application, or PI3B3125QEX equivalent, key selection criteria include its QSOP-16 package, active-low enable logic, 5Ω on-resistance, 4ns max switching speed, and compatibility with 3.3V LVTTL/LVCMOS systems requiring bidirectional, low-distortion signal pass-through.

Technical Context

The PI3B3125QEX implements four independent bidirectional analog switches, each controlled by a dedicated active-low Bus Enable (BE) input. When enabled, the A-side pin connects directly to the B-side pin with no added logic delay-only RC delay from 5Ω R_ON and load capacitance.

It supports rail-to-rail input operation up to +3.6V regardless of V_CC, enabling mixed-voltage interfacing. Power supply sequencing requires V_CC/GND applied before control or data signals to prevent latch-up or ESD stress.

Key Specifications

Pinout & Package

PI3B3125QEX is housed in a 16-pin QSOP (150mil wide) package with exposed pad not present; lead finish is Pb-free and Green-compliant per RoHS 3.

Key Features

Applications

Equivalent & Alternatives

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

Compared with PI3B3125QEX, PI3B3126QEX offers identical performance with reversed enable polarity-ideal for new designs with programmable GPIOs-while SN74CBT3125PWR trades ultra-low power and lower R_ON for broader distributor availability in TSSOP, but sacrifices efficiency and signal fidelity in portable applications.

Availability

PI3B3125QEX is available at Aetrix Electronics and suitable for notebook I/O expansion, embedded display multiplexing, low-power peripheral sharing, and debug interface isolation requiring stable component supply and long-term lifecycle support.

Supply support for PI3B3125QEX 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 semiconductor company specializing in discrete, analog, and mixed-signal solutions, with design, manufacturing, and distribution operations across Asia, the Americas, and Europe.

The PI3B series targets high-speed, low-power logic switching for portable computing and embedded systems, emphasizing rail-to-rail compatibility, nanosecond timing, and green packaging compliance.

FAQ

What is the maximum operating temperature range for PI3B3125QEX?

The PI3B3125QEX is specified for continuous operation from –40°C to +85°C ambient. Junction temperature must not exceed 125°C under any condition, and thermal derating applies above 70°C ambient depending on PCB copper area and airflow. The device uses standard QSOP thermal characteristics with θ_JA ≈ 120°C/W.

Can PI3B3125QEX be used with 1.8V or 2.5V logic levels?

Yes - its logic inputs tolerate –0.5V to +4.6V regardless of V_CC, and it operates correctly with 1.8V or 2.5V signals on A/B pins when V_CC = 3.3V. However, output swing is clamped to V_CC and GND, so 1.8V signals passed through will retain their amplitude but reference the 3.3V domain.

Is there a recommended power supply sequencing order?

Yes - V_CC and GND must be established before applying any signals to A, B, or BE pins. Violating this sequence risks CMOS latch-up or gate oxide stress. Diodes recommends using power-good monitoring or RC delay circuits to ensure V_CC stabilizes ≥100µs before enabling control signals.

Does PI3B3125QEX support hot-plug operation?

No - it is not designed for hot-plug. The device lacks built-in I/O protection for live insertion, and its absolute maximum ratings do not cover transient overvoltage during plug events. For hot-plug applications, external TVS diodes and current-limiting resistors are required on all A/B lines.