onsemi DM74LS125AM

Overview

DM74LS125AM from Fairchild Semiconductor is a quad non-inverting 3-STATE buffer IC in 14-lead SOIC (M14A) package, operating at 4.75–5.25 V supply, with 24 mA low-level output drive, 2.4 V minimum VOH at IOL = 24 mA, and 0.35 V maximum VOL - used for bidirectional bus interfacing in TTL-compatible digital systems.

For engineers reviewing the DM74LS125AM datasheet, pinout, applications, or equivalent options, key selection criteria include guaranteed 3-STATE disable timing (tPLZ/tPHZ ≤ 20 ns), bus-driving capability without pull-ups, and compatibility with LS-TTL logic families across 0°C to +70°C industrial temperature range.

Technical Context

The DM74LS125AM implements four independent buffer gates, each with separate active-low enable control (C input) and non-inverting data path (A → Y). Its 3-STATE outputs use complementary transistor cutoff during disable, achieving high-impedance leakage < ±20 µA at VO = 0.4 V or 2.4 V.

Designed for bus-oriented architectures, it features asymmetric enable/disable timing: tPZH/tPZL (25–40 ns) exceeds tPHZ/tPLZ (≤20 ns), minimizing bus contention risk when multiple buffers share a line. All parameters are specified over VCC = 4.75–5.25 V and TA = 0–70°C.

Key Specifications

Pinout & Package

DM74LS125AM is housed in a 14-lead Small Outline Integrated Circuit (SOIC) package per JEDEC MS-120, 0.150-inch narrow body width, surface-mount compatible with standard reflow profiles.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LS125N and MC74LS125NG, the DM74LS125AM offers identical logic and timing but in a space-saving SOIC package - critical for high-density layouts where board area and reflow compatibility are prioritized over through-hole serviceability.

Availability

DM74LS125AM is available at Aetrix Electronics and suitable for microprocessor bus interface, digital test equipment, and industrial PLC I/O expansion requiring stable component supply and long-term obsolescence management.

Supply support for DM74LS125AM 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

Fairchild Semiconductor was a leading designer of analog and mixed-signal ICs, acquired by ON Semiconductor in 2016; its legacy logic portfolio remains widely deployed in industrial and computing infrastructure.

The DM74LS125AM belongs to the 74LS logic family - engineered for high-speed, low-power TTL-compatible digital interfacing in bus-driven systems from the 1980s onward.

FAQ

What is the operating temperature range for the DM74LS125AM?

The DM74LS125AM is rated for operation from 0°C to +70°C ambient temperature. This industrial-grade range is validated across all electrical specifications including VOH, VOL, and propagation delays. The DM74LS125AM does not support extended or military temperature grades; operation outside this range may result in undefined timing or output behavior.

Does the DM74LS125AM require external pull-up resistors on its outputs?

No, the DM74LS125AM does not require external pull-up resistors when driving standard LS-TTL loads. Its 24 mA low-level output current and 2.4 V minimum VOH at full load provide sufficient drive strength for direct bus interfacing. External resistors are unnecessary unless interfacing with non-TTL logic families or long unterminated transmission lines.

How many enable inputs does the DM74LS125AM have, and what is their polarity?

The DM74LS125AM has four independent active-LOW enable inputs (pins 3, 6, 8, and 11), one per buffer channel. When an enable input is LOW, the corresponding output (Y) follows the A input; when HIGH, that output enters high-impedance state. This polarity allows direct connection to open-collector control signals common in bus arbitration schemes.

What is the maximum capacitive load the DM74LS125AM can drive reliably?

The DM74LS125AM is characterized for CL = 50 pF and CL = 150 pF in its switching characteristics table, with propagation delays increasing predictably (e.g., tPLH from 15 ns to 21 ns). It can reliably drive up to 150 pF without timing violation; beyond that, delay increases and edge degradation may occur - verify with actual board trace capacitance and timing budget.

Is the DM74LS125AM pin-compatible with other 74LS125 variants like SN74LS125N?

Yes, the DM74LS125AM shares identical pinout and logic function with SN74LS125N and MC74LS125NG - all follow the standard 14-pin dual-in-line/SOIC layout for quad 3-STATE buffers. Pin assignments for inputs, outputs, VCC, and GND are fully aligned across these variants, enabling drop-in replacement where package mounting permits.