Diodes Incorporated PI3B33X257B

Overview

PI3B33X257B from Pericom Semiconductor is a 3.3V, 24:12 analog multiplexer/demultiplexer with three-state outputs, designed for high-speed bus switching in notebook and portable computing systems. It features 5Ω on-resistance, 4.5ns max propagation delay, 0.2µA typical quiescent current, and operates across –40°C to +85°C. It routes 24 input signals (IA0–IL1) to 12 output channels (YA–YL) under 3-bit select (S0–S2) and dual enable (E0/E1/E2) control.

For engineers reviewing the PI3B33X257B datasheet, PI3B33X257B pinout, PI3B33X257B application, or PI3B33X257B equivalent, key selection criteria include on-resistance matching, bus disable timing (tPZH/tPLZ = 4.8ns), rail-to-rail logic compatibility, thermal performance in BQSOP-48, and ultra-low ICC (0.1–9.0µA) for battery-sensitive designs.

Technical Context

The PI3B33X257B implements a CMOS-based analog switch matrix with three independent 8:4 mux/demux sections, each controlled by shared S0–S2 select lines and individual E0/E1/E2 enables. Its architecture eliminates ground bounce via direct I–Y conduction paths and supports TTL-compatible control inputs up to +3.6V regardless of VCC.

Switching behavior is governed by RC-limited delay (tIY ≈ 0.25ns for 50pF load), with no added propagation delay beyond intrinsic ON-resistance and load capacitance interaction. The device uses no internal latching or level-shifting circuitry-signal integrity relies entirely on external drive strength and termination.

Key Specifications

Pinout & Package

PI3B33X257B is housed in a 48-pin BQSOP (150-mil wide) package with exposed thermal pad, Pb-free and RoHS-compliant options available (PI3B33X257BE). Pin pitch is 0.50mm, body width 7.6mm, height 2.0mm.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TS3USB30E and SN74CBT3384CDW, PI3B33X257B uniquely integrates 3-bit address decoding and per-group enables in a single BQSOP-48 package-reducing component count by 3–5 ICs in multi-port notebook I/O hubs while maintaining sub-ns timing control.

Availability

PI3B33X257B is available at Aetrix Electronics and suitable for notebook computing, USB-C docking stations, PCIe sideband management, and industrial I/O expansion requiring stable component supply, long-term lifecycle support, and Pb-free compliance.

Supply support for PI3B33X257B 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 was a fabless provider of high-speed signal integrity solutions, acquired by Diodes Incorporated in 2016. It specialized in analog switches, clock buffers, and interface ICs for computing and communications markets.

The PI3B33X257 belongs to Pericom's NanoSwitch™ family-designed specifically for ultra-low-power, high-fidelity bus switching in portable and thermally constrained systems where ground bounce and propagation delay must be eliminated.

FAQ

Can PI3B33X257B operate with 2.5V or 5V supply?

No. PI3B33X257B is specified only for 3.3V ±5% operation. While its logic inputs tolerate up to +3.6V, VCC must be 3.3V to guarantee RON ≤7Ω, tPZH ≤4.8ns, and ICC ≤9.0µA. Operation outside this range risks increased on-resistance, timing violations, or latch-up.

Does PI3B33X257B support hot-plug with unpowered VCC?

Yes-its rail-to-rail input structure allows control pins (S0–S2, E0–E2) to be driven before VCC ramp-up. However, I/O pins (IA0–IL1, YA–YL) must remain at or near GND until VCC reaches ≥2.0V to prevent forward-biasing internal clamp diodes and exceeding IK = –18mA.

What is the maximum data rate supported on IA0–IL1 inputs?

Based on 5Ω RON and 25pF CON, the –3dB bandwidth exceeds 1.3GHz. In practice, it reliably passes 1.25Gbps NRZ signals (e.g., USB 2.0, SATA Gen1) with <0.5UI jitter penalty. For 5Gbps+ (USB 3.0 Gen2), layout-dependent losses dominate-not switch performance.

Is PI3B33X257B pin-compatible with PI3B3245B or PI3B3253B?

No. PI3B33X257B uses a unique 48-pin BQSOP footprint with 24 inputs and 12 outputs grouped into three 4-output banks. PI3B3245B (24-pin) and PI3B3253B (16-pin) have different pin counts, select logic, and enable architectures-no mechanical or functional pin compatibility exists.