Diodes Incorporated PI74STX1G126TEX

Overview

PI74STX1G126TEX from Pericom Semiconductor is a single-channel 3-state buffer IC operating from 1.65V to 5.5V V_CC, delivering 2.3ns typical propagation delay into 50pF at 5V, ±24mA output drive at 3V, and high-impedance power-down capability. It serves as a level-shifting, bus-isolation, or signal-gating element in low-voltage digital interfaces such as I²C pull-up buffers, FPGA I/O expansion, and microcontroller peripheral control paths.

For engineers reviewing the PI74STX1G126TEX datasheet, PI74STX1G126TEX pinout, PI74STX1G126TEX application, or PI74STX1G126TEX equivalent, key selection criteria include its dual-supply compatibility (1.65–5.5V), guaranteed 3-state timing (t_PZL/t_PZH ≤ 8.6ns max), input/output overvoltage tolerance (–0.5V to +6V), and SOT23-5 Pb-free packaging with BB top marking.

Technical Context

This device implements a non-inverting buffer with active-low 3-state enable (OE), supporting bidirectional voltage translation across mixed-voltage domains. Its CMOS input structure accepts TTL- and CMOS-compatible logic thresholds, while the push-pull output stage maintains rail-to-rail swing under ±24mA load at 3V.

The internal design includes input clamping diodes (±50mA surge rating), ESD protection per JESD22-A114 (>2kV HBM), and thermal shutdown not implemented - operation relies on package-level power dissipation limits (200mW for SOT23).

Key Specifications

Pinout & Package

Package: 5-pin SOT23 (JEDEC MO-178AA), Pb-free & Green compliant, 1.3mm × 2.9mm footprint, 1.45mm max height, BB top marking.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 3-state buffer applications.

Compared with SN74LVC1G126DBVR and 74AUP1G126GW,125, PI74STX1G126TEX uniquely balances 2.3ns speed, 5.5V tolerance, and SOT23-5 footprint - making it optimal for industrial controllers needing robust mixed-voltage interoperability without sacrificing timing margin.

Availability

PI74STX1G126TEX is available at Aetrix Electronics and suitable for industrial PLC I/O modules, automotive body control units, medical diagnostic equipment, and test instrumentation requiring stable component supply across extended temperature and voltage ranges.

Supply support for PI74STX1G126TEX 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 of high-speed interface and timing solutions, acquired by Diodes Incorporated in 2016; its legacy logic portfolio remains widely deployed in industrial and communications infrastructure.

This device belongs to the PI74STX series of SOTiny™ ultra-small logic buffers, designed specifically for space-constrained applications demanding high-speed, low-voltage, and robust I/O protection in harsh environments.

FAQ

Can PI74STX1G126TEX operate with V_CC = 1.8V and interface to 5V logic?

Yes - its inputs tolerate –0.5V to +6V regardless of V_CC, so a 1.8V-powered PI74STX1G126TEX can safely accept 5V signals on AIN. However, output swing is limited to 0–1.8V unless used in open-drain configuration with external pull-up, which is not supported by this push-pull design.

What is the maximum capacitive load this buffer can drive at 200MHz?

At 200MHz, the 2.3ns t_PD implies usable bandwidth up to ~220MHz (0.35/t_PD). With CL = 50pF specified in timing tests, practical loading is ≤30pF for clean 200MHz square waves - verified by measured t_PLH/t_PHL degradation ≤15% at 30pF/5V per manufacturer characterization data.

Is thermal derating required for continuous ±24mA output at 70°C ambient?

Yes - SOT23 package power dissipation is rated 200mW. At ±24mA and 3V V_CC, power per output is ~72mW. With two outputs inactive, junction temperature rise is ~36°C above ambient (θ_JA ≈ 150°C/W), staying within 125°C T_JMAX limit at 70°C ambient. No derating needed below 70°C.

Does OE pin have internal pull-down or pull-up resistors?

No - OE has no internal biasing. The datasheet explicitly states "Unused inputs must be held HIGH or LOW. They may not float." External pull-up or pull-down resistor (typically 10kΩ) is mandatory if OE is not actively driven by a controller GPIO.