Diodes Incorporated PI4MSD5V9546ALEX

Overview

PI4MSD5V9546ALEX from Diodes Incorporated is a quad-channel bidirectional I²C bus switch with active-low reset, designed to fan out one upstream SCL/SDA pair to four isolated downstream SCx/SDx channels. It supports voltage translation between 1.2 V, 1.8 V, 2.5 V, 3.3 V, and 5 V buses via VCC-limited pass-gate architecture, features 0 Hz–400 kHz I²C operation, and enables channel selection via programmable control register. Used in multi-voltage sensor hubs and modular I/O expansion systems.

For engineers reviewing the PI4MSD5V9546ALEX datasheet, PI4MSD5V9546ALEX pinout, PI4MSD5V9546ALEX application, or PI4MSD5V9546ALEX equivalent, key selection criteria include its 4-channel I²C switching capability, 5 V-tolerant I/Os, 1.65 V–5.5 V supply range, active-low hardware reset, and dual-package availability (TSSOP-16 and TQFN-16).

Technical Context

The device implements four independent bidirectional analog pass-gate switches controlled by an I²C-compatible state machine. Channel enable/disable is determined by the 4-bit control register (B0–B3), where each bit corresponds to one SCx/SDx pair; multiple bits can be set simultaneously for concurrent channel activation.

Its voltage translation relies on VCC-referenced pass-gate threshold control - Vpass output clamps to ≤VCC, enabling safe inter-bus communication across mismatched logic levels. The RESET pin forces full register reset and channel deselection, while internal POR ensures power-up default (all channels off) at VCC ≥1.3 V.

Key Specifications

Pinout & Package

PI4MSD5V9546ALEX is packaged in a 16-pin TSSOP (L) with 0.65 mm pitch, 173 mil width, and exposed pad not connected. Pin functions are identical across TSSOP and TQFN variants; this entry reflects the L-package configuration used in PI4MSD5V9546ALEX.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TCA9548A and PCA9546A, PI4MSD5V9546ALEX uniquely combines 4-channel switching, 1.2 V–5 V translation, 1.65 V minimum supply, and integrated reset - making it optimal for compact, multi-rail embedded systems requiring fault resilience and minimal external components.

Availability

PI4MSD5V9546ALEX is available at Aetrix Electronics and suitable for multi-sensor hubs, modular I/O expansion systems, server management controllers, and automotive body control modules requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for PI4MSD5V9546ALEX 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 semiconductor company specializing in discrete, analog, and mixed-signal ICs, with manufacturing certified to IATF 16949 and product definitions aligned to AEC-Q standards.

The PI4MSD5V9546A belongs to Diodes' Pericom® interface solutions portfolio, engineered specifically for high-integrity I²C bus expansion and voltage-domain bridging in space-constrained, multi-rail embedded systems.

FAQ

What is the function of the RESET pin, and how must it be connected?

The RESET pin is an active-low asynchronous input that forces the control register to zero and deselects all channels. It must be pulled HIGH to VCC via an external resistor (typically 10 kΩ); asserting RESET LOW for ≥4 ns triggers immediate recovery from stuck-bus conditions. Internal POR performs equivalent reset at power-up when VCC crosses 1.3 V.

Can PI4MSD5V9546ALEX translate between 1.2 V and 5 V I²C buses without external components?

Yes - VCC sets the maximum pass-through voltage (Vpass ≤ VCC). To translate 1.2 V ↔ 5 V, configure VCC to 1.2 V or slightly above (e.g., 1.3 V), ensuring Vpass clamps downstream signals to ≤1.2 V. External pull-ups on each bus set final logic-high levels; no level shifters or resistive dividers are needed.

How does channel selection work, and can multiple channels be active simultaneously?

Channel selection is controlled by bits B0–B3 in the I²C-accessible control register: B0 = CH0, B1 = CH1, B2 = CH2, B3 = CH3. Writing 0x0F enables all four channels concurrently. Activation occurs after STOP condition, ensuring clean bus state transitions and preventing false START/STOP generation during switching.

What package options are available for PI4MSD5V9546ALEX, and how do they differ electrically?

PI4MSD5V9546ALEX uses the TSSOP-16 (L) package: 173 mil width, 0.65 mm pitch, no thermal pad. The ZY variant (TQFN-16, 4 mm × 4 mm) shares identical electrical specs and pinout but offers lower thermal resistance and smaller footprint. Both are Pb-free, RoHS 3 compliant, and halogen-free "Green" devices.