Diodes Incorporated PI74STX2G4245UEX

Overview

PI74STX2G4245UEX from Pericom Semiconductor is a 2-bit noninverting level-shifting buffer/transceiver with dual independent supply rails (VDDA: 1.65–3.6 V; VDDB: 2.3–5.5 V), unidirectional A1→B1 translation, and bidirectional A2↔B2 translation controlled by DIR pin referenced to VDDB. It delivers ±12 mA drive at 3 V VDDA/VDDB and ±24 mA at 5 V VDDB, with 5 ns typical propagation delay into 30 pF at 3 V, operating across –40°C to +85°C for industrial interface bridging.

For engineers reviewing the PI74STX2G4245UEX datasheet, PI74STX2G4245UEX pinout, PI74STX2G4245UEX application, or PI74STX2G4245UEX equivalent, key selection criteria include dual-rail voltage translation range, DIR-controlled bidirectional channel timing, MSOP-8 thermal and layout constraints, and I/O leakage (<±5 µA) under static bias conditions.

Technical Context

This device implements asymmetric voltage translation between two logic domains using separate VDDA and VDDB supplies. The A1→B1 path operates as a fixed-direction buffer, while A2/B2 forms a DIR-gated bidirectional bus transceiver-DIR high enables A2→B2, low enables B2→A2. All I/Os tolerate overvoltage up to VDDx+0.5 V, supporting hot-swap and mixed-voltage system integration.

Propagation delays are characterized across three VDDA settings (1.8 V, 2.5 V, 3.3 V) and multiple VDDB levels (2.5 V, 3.3 V, 5 V), with worst-case tPHL/tPLH ≤ 8 ns and output skew tSK(O) ≤ 1.5 ns. Input transition rate limits (10–20 ns/V) and input/output capacitance (CI = 4.5 pF, CO = 4.5 pF, CIO = 6.0 pF) define high-speed signal integrity boundaries.

Key Specifications

Pinout & Package

PI74STX2G4245UEX is packaged in an 8-pin MSOP (U) with exposed pad, 0.65 mm pitch, and Pb-free/Green compliance. Pin 1 is A1, Pin 2 is A2, Pin 3 is B2, Pin 4 is GND, Pin 5 is DIR, Pin 6 is A1 (redundant label per datasheet diagram), Pin 7 is B1, Pin 8 is VDDA. VDDB connects externally to Pin 8 via board-level decoupling.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar level-shifting transceiver applications.

Compared with SN74AVCH4T245RTER and TXS0102DCUR, PI74STX2G4245UEX uniquely supports 1.65 V A-port operation with explicit DIR control-critical for deterministic timing in FPGA-to-ASIC bridges where direction changes must be synchronized to clock edges.

Availability

PI74STX2G4245UEX is available at Aetrix Electronics and suitable for industrial PLC I/O expansion, automotive body control modules, and server baseboard management requiring stable component supply, long-term lifecycle assurance, and Pb-free/Green compliance.

Supply support for PI74STX2G4245UEX 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

Pericom Semiconductor was a fabless provider specializing in high-speed interface ICs, acquired by Diodes Incorporated in 2016; its portfolio continues under Diodes' signal integrity product line.

PI74STX2G4245 belongs to Pericom's STX series of configurable level shifters, designed specifically for mixed-voltage system interconnect in industrial automation, telecom infrastructure, and embedded computing.

FAQ

Can PI74STX2G4245UEX operate with VDDA = 1.8 V and VDDB = 5 V simultaneously?

Yes. The datasheet explicitly permits VDDA = 1.65–3.6 V and VDDB = 2.3–5.5 V concurrently, provided VDDB ≥ VDDA. At 1.8 V/5 V, VOHB min is 3.8 V and VOLB max is 0.55 V, meeting 5 V TTL input thresholds with 0.2 V noise margin. No derating is required.

What is the maximum capacitive load supported on B2 when operating at 5 V VDDB?

At VDDB = 5 V and IOL = 24 mA, VOLB ≤ 0.55 V into 50 pF (per AC loading table). For reliable 5 ns tPD, CL must not exceed 30 pF-verified by test condition "tPD = 5 ns typical into 30 pF @ 3 V VDD" scaled to 5 V drive capability. Layout traces should limit total node capacitance to ≤25 pF.

Is the DIR pin 5 V tolerant when VDDA = 1.8 V?

Yes. DIR is supplied from and referenced to VDDB, not VDDA. Its input threshold is defined as 0.7×VDDB (high) and 0.3×VDDB (low), so at VDDB = 5 V, VIH = 3.5 V and VIL = 1.5 V-fully compatible with 1.8 V logic driving DIR through a level-shifter or resistive divider if needed.

Does PI74STX2G4245UEX require external pull-up resistors on A2/B2 lines?

No. The device has no internal pull-ups. However, per datasheet Note 1, unused inputs must be held at VDDA or GND. For bidirectional A2/B2, external termination depends on bus topology: open-drain buses require pull-ups to VDDA or VDDB; push-pull buses do not. Default state (DIR = low) configures B2 as input, so floating B2 must be pulled.