Diodes Incorporated PI74STX1G125CX

Overview

PI74STX1G125CX from Diodes Incorporated is a single non-inverting 3-state buffer with 3.3V supply operation, ±24mA output drive, 3ns typical propagation delay, and rail-to-rail input compatibility down to 1.65V. It functions as a level-translating bus driver in low-voltage digital interface circuits such as PCIe Gen1/2 control signaling and FPGA I/O expansion.

For engineers reviewing the PI74STX1G125CX datasheet, PI74STX1G125CX pinout, PI74STX1G125CX application, or PI74STX1G125CX equivalent, key selection criteria include 3.3V-only supply support, 3ns tPLH/tPHL timing at 50pF load, OE-controlled 3-state output with <10ns disable time, and SC-70-5 package thermal performance for space-constrained logic routing.

Technical Context

This device implements a CMOS-based single-channel buffer with active-low output enable (OE), supporting bidirectional voltage translation between 1.65V–3.3V logic domains without external biasing. Its input threshold is VCC-dependent (VTRI = 0.5×VCC ±0.1V), ensuring noise-immune switching across supply variations.

The output stage uses complementary MOSFETs configured for push-pull operation with symmetrical rise/fall times (tr = tf = 3ns typ at CL = 50pF), and features bus-hold circuitry disabled by default-requiring external pull-up/down for floating-input robustness in high-density PCB layouts.

Key Specifications

Pinout & Package

SC-70-5 (SOT-353) package: 1.25mm × 2.10mm footprint, 0.65mm pitch, 0.95mm max height, JEDEC MO-203AA compliant, thermal resistance θJA = 220°C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC1G125DBVR and 74AUP1G125GW,125, the PI74STX1G125CX delivers optimal balance of 3.3V-specific speed (3ns), compact SC-70-5 size, and industrial temperature range-making it preferred for space- and timing-critical 3.3V-only interfaces.

Availability

PI74STX1G125CX is available at Aetrix Electronics and suitable for PCIe configuration buses, FPGA I/O expansion, industrial sensor hubs, and USB-C power delivery control requiring stable component supply and guaranteed long-term sourcing.

Supply support for PI74STX1G125CX 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, specializing in high-reliability, cost-optimized components for industrial, computing, and consumer markets.

The PI74STX series targets high-speed, low-voltage logic interface applications where timing precision, small footprint, and 3.3V compatibility are prioritized over wide-VCC flexibility.

FAQ

Is PI74STX1G125CX compatible with 1.8V input signals?

Yes. Its input threshold is VTRI = 0.5×VCC ±0.1V, and with VCC = 3.3V, VTRI ranges from 1.55V to 1.75V. A 1.8V logic HIGH exceeds this window reliably across temperature and process corners, satisfying VIH(min) = 2.0V specification with margin.

Can OE be left floating during operation?

No. OE is not internally biased and must be actively driven LOW to enable output or HIGH to disable it. Floating OE may cause undefined output states due to noise coupling; a 10kΩ pull-down resistor is recommended for default-disabled operation.

What is the maximum capacitive load this buffer can drive reliably?

The datasheet specifies timing parameters up to CL = 50pF. While the output can physically drive >100pF, propagation delay increases linearly beyond 50pF (e.g., ~4.5ns at 100pF), and signal integrity degrades above 150pF without series termination. For designs exceeding 50pF, verify timing margins with IBIS simulation.

Does PI74STX1G125CX support hot-swap insertion?

No. It lacks powered-off protection and bus-fault immunity. Inserting or removing the device while VCC is applied risks latch-up or output-stage damage due to uncontrolled voltage sequencing. Always power down the system before handling.