Diodes Incorporated PI4ULS5V212UEX

Overview

PI4ULS5V212UEX from Diodes Incorporated is a 2-channel, bidirectional I²C-bus/SMBus repeater IC with voltage-level translation between 0.6V–5.5V (Port A) and 2.2V–5.5V (Port B), supporting Fast-mode Plus (1 MHz) operation, 540 pF bus capacitance per side at full speed, and open-drain I/Os with 5V-tolerant EN, SDA, and SCL pins. It enables mixed-voltage I²C systems such as 0.95V sensor nodes interfacing to 3.3V microcontrollers in industrial IoT edge devices.

For engineers reviewing the PI4ULS5V212UEX datasheet, PI4ULS5V212UEX pinout, PI4ULS5V212UEX application, or PI4ULS5V212UEX equivalent, key selection criteria include bidirectional level-shifting capability across asymmetric supply rails, propagation delay asymmetry (76–210 ns), static offset handling on Port B, latching-free arbitration support, and MSOP-8 footprint compatibility with legacy PI4ULS5V212 designs.

Technical Context

The PI4ULS5V212UEX implements dual independent bidirectional open-drain buffers with separate reference thresholds: Port A uses dynamic 0.33×VCC(A) low-input threshold for sub-1V logic compatibility, while Port B employs fixed static offset (≈0.55V VOL) to prevent lockup during bus contention. Its internal power-up sequencing ensures drivers remain disabled until VCC(B) ≥ 2.2V and internal references settle (~400 μs), enabling robust hot-swap and unpowered high-impedance I/O behavior.

It supports full I²C protocol integrity-including arbitration, clock stretching, multi-master operation-and accommodates Standard-mode (100 kHz), Fast-mode (400 kHz), and Fast-mode Plus (1 MHz) devices, SMBus (standard/high-power), and PMBus. The EN pin-referenced to VCC(B) with 0.7×VCC(B) VIH-is designed for system-controlled isolation during power-up or fault recovery, but must only toggle during bus idle states to avoid hang conditions.

Key Specifications

Pinout & Package

Package: 8-pin MSOP-8 (U), 3.0 mm × 3.0 mm × 1.1 mm body, 0.65 mm pitch, RoHS-compliant, halogen- and antimony-free "Green" construction.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TCA9517PWR and PCA9515DP, the PI4ULS5V212UEX uniquely supports 0.6V logic on Port A with adaptive input thresholds, enables star-topology connections via Port A, and provides automatic channel disable during unsafe supply sequencing-making it the only option for mixed-voltage IoT sensor hubs and wearable subsystems.

Availability

PI4ULS5V212UEX is available at Aetrix Electronics and suitable for industrial sensor hubs, automotive body control modules, medical wearable data aggregators, and server baseboard management controllers requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant "Green" packaging.

Supply support for PI4ULS5V212UEX 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 solutions for power management, signal integrity, and protection applications.

The PI4ULS5V212UEX belongs to Diodes' Pericom® I²C/SMBus repeater product line, engineered specifically for voltage-domain bridging in mixed-supply embedded systems-prioritizing sub-1V compatibility, protocol transparency, and robust ESD performance.

FAQ

Can PI4ULS5V212UEX operate with VCC(A) = 0.6V and VCC(B) = 2.2V simultaneously?

Yes. The device is fully specified for this condition: VCC(A) ≥ 0.6V and VCC(B) ≥ 2.2V meet absolute minimum ratings, and the 0.4×VCC(A) + 0.8V ≤ VCC(B) constraint evaluates to 1.04V ≤ 2.2V-ensuring functional enablement. At these voltages, Port A VIL = 0.2V (0.33×0.6V), providing adequate noise margin for 0.6V logic.

What happens to SDA/SCL pins when VCC(B) = 0V but VCC(A) = 3.3V?

All SDA and SCL pins enter high-impedance state regardless of VCC(A) voltage, because internal logic and drivers are powered solely by VCC(B). With VCC(B) = 0V, the device is fully unpowered, and I/Os present >10 MΩ impedance-safe for hot-plug or partial-power-down scenarios without signal contention.

Why does Port B have a ~0.55V VOL while Port A achieves near-0V VOL?

Port B's static offset (~0.55V) prevents latch-up during bus contention by ensuring its internal LOW is not recognized as a valid LOW by other Port B drivers-avoiding deadlock in cascaded configurations. Port A uses near-0V VOL to match ultra-low-voltage logic thresholds (e.g., 0.2V at 0.6V supply), enabling clean signal restoration on the low-voltage side.

Is PI4ULS5V212UEX compatible with SMBus Alert Response Address (ARA) protocol?

Yes. As a transparent, latching-free repeater that preserves all I²C/SMBus signaling-including START, STOP, repeated START, ACK/NACK, and clock stretching-the PI4ULS5V212UEX fully supports SMBus ARA. The EN pin must remain HIGH during ARA transactions, and bus timing budgets must account for added propagation delays (≤210 ns).