Diodes Incorporated PI3A125BCEX

Overview

PI3A125BCEX from Diodes Incorporated (acquired Pericom Semiconductor) is a single-pole single-throw (SPST), normally closed (NC) CMOS analog switch optimized for low-distortion audio/video signal routing. It delivers 8Ω on-resistance at 3.0V, 500MHz –3dB bandwidth, and –63dB off-isolation at 10MHz, operating from 1.65V to 6.0V supply with rail-to-rail signal handling in portable instrumentation and telecom interfaces.

For engineers reviewing the PI3A125BCEX datasheet, PI3A125BCEX pinout, PI3A125BCEX application, or PI3A125BCEX equivalent, key selection criteria include on-resistance flatness (<6Ω over full signal range at 5V), break-before-make switching behavior, power-off protection on I/O pins, and control input overvoltage tolerance up to 6.0V independent of V+.

Technical Context

The PI3A125BCEX implements a voltage-controlled transmission gate architecture using CMOS process technology, enabling bidirectional analog signal conduction with minimal distortion. Its logic-controlled IN pin directly opens the NC path when driven high, supporting TTL- and CMOS-compatible thresholds across the full 1.65–6.0V V+ range.

Designed for wide-bandwidth signal integrity, it achieves 2ns transition speed at 5.0V and maintains <5pC charge injection-critical for sample-and-hold and precision multiplexing. The device guarantees break-before-make timing to prevent signal shorting during state transitions and includes integrated power-off protection that disables I/O leakage when V+ = 0V.

Key Specifications

Pinout & Package

PI3A125BCEX is packaged in a Pb-free, RoHS-compliant 5-pin SC70 (SOT-353) package, measuring 2.0 × 1.25 × 0.9 mm with gull-wing leads and pin 1 marked by a dot.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar analog switch applications.

Compared with TS5A23157DCUR and ADG849YKSZ-REEL7, PI3A125BCEX uniquely combines NC default, 6.0V overvoltage-tolerant control, and power-off protection - making it optimal for battery-powered systems requiring fail-safe signal isolation without added support circuitry.

Availability

PI3A125BCEX is available at Aetrix Electronics and suitable for audio routing, HD video multiplexing, and portable instrumentation requiring stable component supply and long-term lifecycle support.

Supply support for PI3A125BCEX 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 acquired Pericom Semiconductor in 2017 and integrates its high-performance analog switch portfolio into broader signal integrity solutions for consumer, industrial, and communications markets.

The PI3A125BCEX belongs to Pericom's legacy wide-bandwidth analog switch product line, engineered specifically for low-distortion, rail-to-rail signal routing in space-constrained, battery-operated devices where power-off safety and mixed-voltage interoperability are essential.

FAQ

What is the default state of PI3A125BCEX when power is applied?

The PI3A125BCEX is a normally closed (NC) switch: when IN is LOW or floating (with pull-down), the COM–NC path is conductive. It opens only when IN is actively driven HIGH. This default-closed behavior ensures signal continuity during power-up or control failure, critical for fail-safe audio and sensor interfaces.

Can PI3A125BCEX operate with a 1.65V supply while switching 3.3V analog signals?

Yes - the device supports rail-to-rail analog signal ranges from GND to V+, so with V+ = 1.65V, it passes signals from 0V to 1.65V. To switch 3.3V signals, V+ must be ≥3.3V. The control input remains functional up to 6.0V regardless of V+, enabling independent logic-level interfacing.

Does PI3A125BCEX require external pull-up or pull-down resistors on the IN pin?

Yes - the IN pin must not float. A pull-down resistor (e.g., 100kΩ to GND) ensures default LOW state and NC closure during power-up or microcontroller reset. Pull-up is used only when active-HIGH enable is required. Floating IN may cause undefined switching and increased supply current due to input stage instability.

Is PI3A125BCEX pin-compatible with PI5A3167C?

No - PI3A125BCEX uses SC70-5 (pin 1 = IN, pin 2 = COM, pin 3 = GND, pin 4 = NC, pin 5 = V+), while PI5A3167C is a dual SPDT switch in SOT363 with different pinout, logic polarity, and signal routing. Diodes recommends PI5A3167C as a functional upgrade path, not a drop-in replacement.