Diodes Incorporated PI3B16224B

Overview

PI3B16224B from Pericom Semiconductor is a 3.3V, 12-bit to 24-bit bidirectional analog bus switch (NanoSwitch™) with 5Ω typical R_ON, 4.5ns max propagation delay, and 500Ω pulldown resistors on unconnected B ports-designed for high-speed memory bus switching in DDR SDRAM DIMM modules.

For engineers reviewing the PI3B16224B datasheet, PI3B16224B pinout, PI3B16224B application, or PI3B16224B equivalent, key selection criteria include on-resistance matching across channels, rail-to-rail logic compatibility (0–3.6V input), industrial temperature support (–40°C to +85°C), and BQSOP-40 package thermal performance in dense memory subsystems.

Technical Context

The PI3B16224B implements a dual 12×24 demux/mux architecture with independent A/B port pairs and a single enable control (S1). Each channel operates as a low-impedance pass gate without internal level shifting or buffering.

All 24 B-side terminals feature integrated 500Ω pulldown resistors to prevent floating states when disconnected; the device uses no internal latches or clocking-functionality is purely combinational and voltage-controlled.

Key Specifications

Pinout & Package

Package: 40-pin BQSOP (Body: 10.16mm × 7.49mm, Pitch: 0.635mm), Pb-free & RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with PI3B3244B and SN74CBT16212DGGR, the PI3B16224B uniquely delivers 24-channel 3.3V switching with integrated B-port termination-making it the sole fit for DDR DIMM bus expansion without external biasing.

Availability

PI3B16224B is available at Aetrix Electronics and suitable for DDR SDRAM DIMM switching, memory interleaving hubs, hot-pluggable memory modules, and industrial PLC memory expansion requiring stable component supply and long-term lifecycle assurance.

Supply support for PI3B16224B 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 (acquired by Diodes Incorporated in 2016) specialized in high-speed interface and signal-integrity solutions for computing and communications infrastructure.

The PI3B16224B belongs to Pericom's NanoSwitch™ bus switch product line, engineered specifically for low-skew, low-R_ON memory and data-path routing in DDR1/DDR2 systems.

FAQ

Is PI3B16224B compatible with DDR2 memory timing requirements?

Yes. With ≤4.5ns propagation delay and 5Ω R_ON, the PI3B16224B meets DDR2-400 (200MHz) setup/hold timing budgets when used with ≤50pF load capacitance and proper PCB layout. Its RC-limited delay adds <0.3ns to signal path-well within DDR2 margin.

Can PI3B16224B operate with V_CC = 3.0V while driving 3.6V logic inputs?

Yes. The device accepts input voltages from –0.5V to +4.6V independent of V_CC. At V_CC = 3.0V, it correctly interprets 3.6V logic HIGH on S1 or A/B ports, enabling interoperability with higher-voltage controllers without level shifters.

What is the function of the 500Ω pulldown resistors on B ports?

These resistors ensure B1–B24 terminals default to logic LOW when disconnected from a DIMM or other load. This prevents floating inputs from causing metastability or false triggering in downstream receivers during hot-plug, partial population, or initialization sequences.

Does PI3B16224B support hot-swap power sequencing?

It supports controlled sequencing: V_CC and GND must be applied before signals. The device lacks internal charge pumps or power-on reset, so external sequencing (e.g., using a supervisor IC) is required to assert S1 only after V_CC stabilizes-ensuring reliable turn-on without latch-up.