onsemi SN74LS38MR1

Overview

SN74LS38MR1 from ON Semiconductor is a quad 2-input NAND buffer with open-collector outputs, designed for wired-AND logic and level translation in TTL-compatible systems. It operates at 4.75–5.25 V, delivers 24 mA sink current per output, and features 18–32 ns propagation delay at 25°C. It is used in address decoding, bus arbitration, and interface buffering in industrial control panels.

For engineers reviewing the SN74LS38MR1 datasheet, pinout, applications, or equivalent options, key selection criteria include open-collector drive capability, guaranteed 0.4 V VOL at 24 mA, −0.65 V input clamp voltage, and SOEIAJ-14 package compatibility with JEDEC MS-012 footprints.

Technical Context

The SN74LS38MR1 implements four independent TTL-compatible NAND gates with open-collector outputs, requiring external pull-up resistors to define HIGH-level logic states. Its Schottky-clamped bipolar architecture ensures low propagation delay and reduced saturation delay compared to standard TTL.

Each gate accepts standard LS-TTL input thresholds (VIH ≥ 2.0 V, VIL ≤ 0.8 V) and provides robust input clamping (VIK = −0.65 V) and controlled output sinking (IOL = 24 mA, VOL = 0.4 V max at IOL = 24 mA), enabling reliable interfacing with mixed-voltage subsystems.

Key Specifications

Pinout & Package

SN74LS38MR1 is housed in a 14-pin SOEIAJ (Small Outline EIAJ) package, case 965, with gull-wing leads and 1.27 mm pitch. The package meets JEDEC MS-012 mechanical standards and is compatible with standard surface-mount reflow profiles.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar NAND buffer applications.

Compared with SN74LS03DR and SN74LS10N, the SN74LS38MR1 uniquely combines SOEIAJ-14 packaging, 24 mA open-collector sink capability, and −0.65 V input clamping-making it irreplaceable in legacy industrial designs requiring robust wired-AND bus interfaces with high immunity to negative transients.

Availability

SN74LS38MR1 is available at Aetrix Electronics and suitable for industrial control panels, legacy test equipment, and automotive diagnostic tools requiring stable component supply and long-term obsolescence management.

Supply support for SN74LS38MR1 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

ON Semiconductor (now onsemi) is a global semiconductor manufacturer specializing in power management, analog, sensor, and logic solutions for automotive, industrial, and cloud power applications.

The SN74LS38MR1 belongs to the legacy LS-TTL logic family, engineered specifically for reliability in industrial environments where wired-AND logic, level translation, and robust input protection are critical design requirements.

FAQ

What is the maximum output sink current specification for SN74LS38MR1?

The SN74LS38MR1 is guaranteed to sink up to 24 mA per output while maintaining VOL ≤ 0.4 V at VCC = 4.75 V and TA = 70°C. This rating enables direct driving of LEDs, small relays, and multiple LS-TTL inputs without external buffering. The SN74LS38MR1's open-collector architecture requires external pull-up resistors to define HIGH-level logic states.

Does SN74LS38MR1 support wired-AND logic connections?

Yes, SN74LS38MR1 supports wired-AND logic through its four open-collector outputs. When multiple outputs are tied together with a single pull-up resistor, the combined node goes LOW if any output is active, enabling bus arbitration and priority encoding. This functionality is intrinsic to the SN74LS38MR1's output structure and does not require additional components.

What package type is used for SN74LS38MR1?

SN74LS38MR1 uses the SOEIAJ-14 package (case 965), a gull-wing surface-mount outline with 1.27 mm lead pitch and JEDEC MS-012 compliance. It differs from standard SOIC-14 in lead form and body dimensions, requiring specific stencil and placement settings. The SN74LS38MR1's SOEIAJ footprint is documented in ON Semiconductor's case 965−01 mechanical drawing.

What is the input clamp voltage (VIK) specification for SN74LS38MR1?

The SN74LS38MR1 features an input clamp diode with VIK = −0.65 V (min) at VCC = 4.75 V and IIN = −18 mA. This protects inputs from negative transients such as relay coil flyback or ESD events. The SN74LS38MR1's clamping performance remains effective down to −1.5 V, ensuring robustness in electrically noisy industrial environments.

Can SN74LS38MR1 operate outside the standard 0°C to 70°C ambient range?

No, SN74LS38MR1 is specified only for 0°C to 70°C operating ambient temperature. Its DC and AC parameters-including VOL, IOL, and propagation delay-are guaranteed only within this range. Using SN74LS38MR1 outside this range may result in undefined behavior or parametric failure, and no extended temperature variants (e.g., −40°C to +85°C) exist for this part number.