Diodes Incorporated PI5C3125QE

Overview

PI5C3125QE from Pericom Semiconductor is a 4-bit bus switch IC with four independent 5Ω analog switches, active-low enable inputs, and industry-standard 74XX125 pinout. It provides near-zero propagation delay (0.25 ns), ultra-low quiescent current (0.1 µA typical), and operates from 4.5 V to 5.5 V - used in notebook I/O isolation and high-speed data path gating.

For engineers reviewing the PI5C3125QE datasheet, PI5C3125QE pinout, PI5C3125QE application, or PI5C3125QE equivalent, key selection criteria include individual enable control per channel, 5 Ω on-resistance at 5 V, 50 pF load propagation behavior, and QSOP-16 packaging compatibility with legacy 74-series layouts.

Technical Context

The PI5C3125QE implements four independent bidirectional analog switches controlled by separate active-low BE0–BE3 signals. Each switch connects A_n to B_n with no logic inversion or timing skew when enabled, and presents high-impedance (Hi-Z) isolation when disabled.

It uses CMOS transmission-gate architecture with rail-to-rail analog signal handling (–0.5 V to +7.0 V), supports 120 mA DC output current per channel, and exhibits <6 pF input capacitance and <8 pF on-state A/B capacitance - enabling clean signal integrity in 5 V TTL/CMOS data buses.

Key Specifications

Pinout & Package

PI5C3125QE is housed in a 16-pin, 150-mil wide QSOP (Q) package with Pb-free & Green compliance. Pin 1 is V_CC, pin 16 is GND, and pins 9–12 and 14–15 are dedicated to A/B signal pairs and BE controls.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74CBT3125DBQR and 74LVC1G3157GW, the PI5C3125QE offers native active-low enables and integrated quad-channel layout in QSOP-16 - reducing board area and eliminating enable inversion logic required by the TI part, while avoiding the component count and routing complexity of the NXP SPDT solution.

Availability

PI5C3125QE is available at Aetrix Electronics and suitable for laptop I/O isolation, PCIe lane multiplexing, and industrial backplane switching requiring stable component supply and long-term lifecycle assurance.

Supply support for PI5C3125QE 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

Pericom Semiconductor (now part of Diodes Incorporated) specialized in high-speed interface and signal-integrity solutions for computing, communications, and consumer electronics before its 2016 acquisition.

The PI5C3125QE belongs to Pericom's 5C logic family targeting low-power, low-distortion bus switching - designed specifically for replacing 74-series logic in battery-powered and thermally constrained systems.

FAQ

What is the maximum signal voltage the PI5C3125QE can pass when V_CC = 5 V?

The PI5C3125QE supports analog signal levels from –0.5 V to +7.0 V on A and B pins regardless of V_CC, enabling rail-to-rail operation beyond the supply rail. This allows safe passage of 5 V TTL, 3.3 V LVTTL, and even negative-going transients within absolute maximum ratings.

Does the PI5C3125QE require external pull-up resistors on the BE pins?

Yes - a pull-up resistor is recommended on each BE pin for power-up protection, as the device powers up with all switches disabled (Hi-Z state) only if BE pins are held high. Without pull-ups, undefined enable states may cause unintended conduction or bus contention during reset.

Can the PI5C3125QE be used with 3.3 V logic systems?

Yes - although optimized for 5 V operation, the PI5C3125QE accepts 3.3 V control signals (V_IL ≤ 0.8 V, V_IH ≥ 2.0 V) and passes 3.3 V data bidirectionally. However, R_ON increases to ~10 Ω at V_CC = 3.3 V, and full 5 V supply is required for guaranteed 5 Ω performance and 120 mA drive capability.

Is there a pin-compatible 3.3 V–only version of this device?

No - Pericom did not release a 3.3 V–only variant of the PI5C3125. The PI3CH480 (3.3 V, 8-bit, active-high enable) and SN74CBTD3384 (3.3 V, 10-bit, active-low) offer similar functionality but differ in channel count, enable polarity, and package, making them non-drop-in replacements.