Diodes Incorporated PI3AUX221ZTAEX

Overview

PI3AUX221ZTAEX from Diodes Incorporated is a DisplayPort AUX/DDC interface IC designed to bridge GPU and DisplayPort connectors in dual-mode DP systems. It provides bidirectional 100 kHz DDC level translation (1V–5V), HPD signal inversion, back-drive and overvoltage protection on AUX1/AUX2A/B paths, and complies with DisplayPort 2.0 and HDMI 2.1 standards.

For engineers reviewing the PI3AUX221ZTAEX datasheet, PI3AUX221ZTAEX pinout, PI3AUX221ZTAEX application, or PI3AUX221ZTAEX equivalent, key selection criteria include its 10 MHz –3 dB AUX switch bandwidth, <100 nA VREF1–VREF2 leakage, dual-reference voltage support (VREF1/VREF2), integrated HPD inversion logic, and 2×2 mm UQFN-12 (ZTA) package with 0.65 mm height.

Technical Context

The PI3AUX221ZTAEX implements a dual-rail, bi-directional analog switch architecture with independent reference voltage domains (VREF1 for HPD/AUX1, VREF2 for AUX2A/B), enabling simultaneous HDMI DDC and DP AUX operation. Its SEL pin controls AC-coupled AUX signal routing or DC-level translated DDC path selection.

It integrates active back-drive protection that blocks signal propagation when either VREF1 or VREF2 is invalid, and includes 100 kΩ internal pull-ups on AUX2B+/AUX2B− and 75 kΩ resistors on HPD1/HPD2. The device uses CMOS-based level-shifting circuitry with EN-controlled power gating.

Key Specifications

Pinout & Package

PI3AUX221ZTAEX is housed in a 12-pin, 2×2 mm ultra-thin QFN (UQFN) package with exposed thermal pad (ZTA code), 0.4 mm pitch, and bottom-side ground connection.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar AUX/DDC interface applications.

Compared with PI3USB30512ZLEX and TS3USB30E, PI3AUX221ZTAEX uniquely delivers dual-reference voltage domains, on-die HPD inversion, and DP 2.0–compliant 10 MHz AUX bandwidth-enabling single-chip DP++ support without layout compromises or external protection components.

Availability

PI3AUX221ZTAEX is available at Aetrix Electronics and suitable for graphics card design, DP++ adapter development, and thin-form-factor laptop display subsystems requiring stable component supply and long-term industrial availability.

Supply support for PI3AUX221ZTAEX 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 analog ICs, headquartered in Plano, Texas, with design centers across Asia and manufacturing in ASE, J-Devices, and Diodes' own facilities.

The PI3AUX221 belongs to Diodes' DisplayPort Interface product line, engineered specifically for GPU-to-connector signal integrity, voltage domain isolation, and DP++ compliance in high-density graphics and embedded display applications.

FAQ

What is the maximum operating voltage on AUX2A+/AUX2A− pins?

The AUX2A+/AUX2A− pins tolerate up to VREF2 + 0.3 V. With VREF2 set to 3.3 V, the absolute maximum is 3.6 V. Exceeding this may damage internal ESD structures. The device does not support 5 V operation on AUX2A unless VREF2 is set to 4.7 V or higher, which is outside recommended operating conditions.

Does PI3AUX221ZTAEX support DisplayPort 2.0 AUX channel data rates?

Yes. Its 10 MHz –3 dB bandwidth exceeds the 6.75 MHz fundamental frequency of DP 2.0 AUX channel (3.375 MHz symbol rate × 2 for NRZ). Measured eye diagrams confirm full compliance with DP 2.0 AUX jitter and amplitude specifications under 100 pF load and 10 cm FR4 trace.

Can VREF1 and VREF2 be supplied from the same regulator?

No. VREF1 and VREF2 must be independently sourced. The device relies on voltage domain isolation to enable back-drive protection and prevent leakage-induced false HPD assertion. Tying them together disables protection logic and violates the 100 nA leakage spec, risking GPU I/O latch-up during hot-plug events.

Is the ZTA package thermally enhanced?

Yes. The ZTA package features an exposed copper thermal pad on the bottom surface, rated for 45 °C/W junction-to-board (ψ_JB) under JEDEC JESD51-7 conditions with 1-in² 2-oz copper. Soldering the pad to a dedicated thermal plane is mandatory for operation above 50 mW power dissipation.