Diodes Incorporated PI6ULS5V9509UEX

Overview

PI6ULS5V9509UEX from Diodes Incorporated is a bidirectional I²C/SMBus level-translating repeater in an 8-pin MSOP package. It isolates bus capacitance between two voltage domains (1.1V–(V_CC(B)−1.0V) on Port A and 2.5V–5.5V on Port B), supports 400 kHz operation, enables arbitration and clock stretching across ports, and prevents bus lock-up via current-sensing LOW detection on Port A - used in mixed-voltage server management and embedded sensor subsystems.

For engineers reviewing the PI6ULS5V9509UEX datasheet, PI6ULS5V9509UEX pinout, PI6ULS5V9509UEX application, or PI6ULS5V9509UEX equivalent, key selection considerations include dual-supply level translation range, port-specific input thresholds (V_ILC = +0.15 V on Port A), propagation delay asymmetry (t_PLH A→B: −69 ns typ), and EN pin timing constraints (100 ns setup/hold relative to START/STOP).

Technical Context

The PI6ULS5V9509UEX implements asymmetric buffering: Port A uses a 1 mA current-source pull-up and 200 Ω pull-down with a 0.2 V output LOW and 0.15 V input threshold (V_ILC) to avoid contention-induced lock-up; Port B employs open-drain drivers compliant with SMBus I/O levels (V_IL = 0.3×V_CC(B), V_OL = 0.1–0.2 V at 6 mA).

Enable logic requires both V_CC(A) > 0.8 V and V_CC(B) > 2.5 V for activation, and the EN pin must only transition during bus idle states. Propagation delays are directionally asymmetric: A→B t_PLH can be negative (−69 ns typ), while B→A t_PLH is positive (65–75 ns typ), reflecting internal signal-sampling timing alignment.

Key Specifications

Pinout & Package

Package: 8-pin MSOP (U), surface-mount, RoHS-compliant, moisture sensitivity level 1.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar I²C level-translating repeater applications.

Compared with TCA9617A and PCA9306, the PI6ULS5V9509UEX uniquely supports continuous low-voltage supply tracking (1.1 V to V_CC(B)−1 V), eliminates external pull-ups on Port A, and guarantees lock-up-free operation - making it the only choice for dynamically scaled, high-node-count, or safety-critical I²C extensions.

Availability

PI6ULS5V9509UEX is available at Aetrix Electronics and suitable for server baseboard management, automotive body control modules, and industrial PLC I/O expansion requiring stable component supply, long-term lifecycle support, and guaranteed RoHS/Green compliance.

Supply support for PI6ULS5V9509UEX 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 ICs, specializing in high-performance, high-reliability components for industrial, computing, and automotive markets.

The PI6ULS5V9509UEX belongs to Diodes' Pericom® interface solutions portfolio, designed specifically for robust, protocol-transparent I²C/SMBus extension in mixed-voltage embedded systems with stringent reliability and timing requirements.

FAQ

Can PI6ULS5V9509UEX operate with V_CC(A) = 1.1 V and V_CC(B) = 2.5 V simultaneously?

Yes. The device is fully specified for this condition: Port A supports 1.1 V minimum, and Port B supports 2.5 V minimum. At these rails, V_ILC remains +0.15 V (ensuring lock-up immunity), and t_PHL A→B is 20–183 ns - within I²C Fast-mode timing budgets. Current consumption is 1.25–5 mA on Port A and 0.5–1.1 mA on Port B.

What happens if the EN pin is toggled during an I²C transaction?

Toggling EN mid-transaction risks bus corruption: the repeater disables asynchronously, potentially freezing SDA/SCL in LOW state or causing incomplete ACK/NACK cycles. Diodes specifies strict 100 ns setup/hold timing relative to START/STOP edges. System firmware must assert EN only after STOP and before next START - verified via oscilloscope capture in Application Note AN-5012.

Does PI6ULS5V9509UEX support I²C Fast-mode Plus (1 MHz)?

No. The datasheet specifies 0 Hz to 400 kHz maximum clock frequency. Although some propagation delays (e.g., t_THL B = 1–40 ns) suggest higher potential, the device's internal current-sensing comparator bandwidth and guaranteed timing margins are validated only up to 400 kHz. Attempting 1 MHz may cause missed edges or arbitration failure.

Is there a recommended layout practice for minimizing noise coupling between Port A and Port B?

Yes: maintain separate ground pour regions for each port beneath the MSOP footprint, joined only at a single point near Pin 4 (GND); route A1/A2 and B1/B2 differentially with matched lengths and ≥3× trace spacing; place 100 nF ceramic decoupling caps ≤2 mm from V_CC(A) and V_CC(B) pins. These practices reduce crosstalk-induced false triggering observed in DS41884 Figure 7 waveforms.