Diodes Incorporated PI4MSD5V9543AWEX

Overview

PI4MSD5V9543AWEX from Diodes Incorporated is a 2-channel bidirectional I²C bus switch with integrated interrupt logic and active-low reset, designed for voltage-level translation between mixed-voltage I²C subsystems (1.2 V to 5 V). It features programmable channel selection via I²C control register, 5 V-tolerant I/O pins, 400 kHz Fast Mode support, and low Ron (≤9 Ω at 5 V) pass-gate switches - enabling reliable interconnection of sensors, PMICs, and EEPROMs across heterogeneous voltage domains in industrial control modules.

For engineers reviewing the PI4MSD5V9543AWEX datasheet, PI4MSD5V9543AWEX pinout, PI4MSD5V9543AWEX application, or PI4MSD5V9543AWEX equivalent, key selection criteria include its dual-interrupt input architecture (INT0/INT1), AND-combined open-drain INT output, power-up default deselection behavior, and VCC-dependent voltage clamping capability for safe level translation without external protection circuitry.

Technical Context

This device implements a dual-channel, I²C-addressable analog multiplexer using NMOS pass-gate topology with body-bias control to enable bidirectional signal flow and voltage translation. Its internal state machine decodes I²C commands to set B0/B1 bits in an 8-bit control register, directly enabling SC0/SD0 or SC1/SD1 channels - with no glitch on power-up and automatic deselection after RESET or POR.

The interrupt handling logic monitors INT0 and INT1 asynchronously, latching their states into bits 4 and 5 of the control register; the open-drain INT output reflects logical AND of both inputs. The RESET pin forces full register initialization and channel deselection, while VCC sets the maximum pass-through voltage (Vpass) - e.g., 3.3 V supply limits translated outputs to ≤2.8 V, protecting 2.5 V downstream devices.

Key Specifications

Pinout & Package

PI4MSD5V9543AWEX is housed in a 14-pin SOIC-14W (150 mil wide) package with standard JEDEC outline, surface-mount compatible, and RoHS-compliant (Pb-free/Green).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar I²C bus switching applications.

Compared with TCA9548A and PCA9546A, PI4MSD5V9543AWEX uniquely integrates dual-interrupt monitoring, VCC-configurable voltage clamping, and sub-2 V operation - making it the only option among the three that supports autonomous fault detection and safe 1.2 V ↔ 5 V translation in compact 2-channel systems.

Availability

PI4MSD5V9543AWEX is available at Aetrix Electronics and suitable for industrial sensor hubs, multi-rail PMIC monitoring, and hot-swappable I/O cards requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant packaging.

Supply support for PI4MSD5V9543AWEX 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 manufacturer of discrete semiconductors and integrated circuits, specializing in high-performance, energy-efficient components for automotive, industrial, computing, and consumer markets.

PI4MSD5V9543AWEX belongs to Diodes' I²C interface and bus management product line, engineered specifically to simplify mixed-voltage system integration while reducing component count and improving bus reliability in space-constrained embedded designs.

FAQ

What is the minimum VCC required for reliable operation with 1.2 V downstream I²C devices?

The PI4MSD5V9543AWEX operates down to 1.65 V VCC, but for safe 1.2 V bus translation, VCC must be set such that Vpass ≤1.2 V. Per the datasheet's Vpass vs. VCC curve, this requires VCC ≤1.8 V. At 1.65 V VCC, Vpass is ~0.54 V (min) to 1.3 V (max), ensuring clamping below 1.2 V under worst-case conditions - enabling direct interfacing with 1.2 V slaves without risk of overvoltage damage.

How does the interrupt logic resolve which downstream channel generated an interrupt?

The PI4MSD5V9543AWEX latches the instantaneous states of INT0 and INT1 into bits 4 and 5 of its readable control register. When the I²C master reads the register, bit 4 = 1 indicates INT0 asserted, bit 5 = 1 indicates INT1 asserted. The master then writes to B0/B1 bits to enable the corresponding SCx/SDx channel, allowing direct interrogation of the suspect downstream device - eliminating blind polling across both buses.

Can both channels be enabled simultaneously, and what design constraint applies?

Yes, the control register allows simultaneous enabling of SC0/SD0 and SC1/SD1 via B0=1 and B1=1. However, the datasheet explicitly warns that total bus capacitance must remain ≤400 pF - enabling both channels doubles capacitive loading on the upstream SDA/SCL lines. Designers must verify combined trace + device + pull-up capacitance stays within limit, especially at 400 kHz Fast Mode, to avoid timing violations or signal integrity loss.

Is external pull-up resistance required on INT0 and INT1 when used as general-purpose inputs?

Yes - if INT0 or INT1 are repurposed as general-purpose digital inputs (not interrupt sources), they must be externally pulled HIGH to VCC via a resistor (typically 10 kΩ). Leaving them floating violates the absolute maximum rating for input voltage and risks metastability or excessive current draw due to undefined CMOS input thresholds. The datasheet mandates this for all unused interrupt inputs.