onsemi SN74LS368AML1

Overview

SN74LS368AML1 from ON Semiconductor is a hex 3-state inverting buffer with separate 2-bit and 4-bit sections, designed for TTL-level bus interface and data routing. It operates at 4.75–5.25 V, delivers 24 mA sink current per output, supports −2.6 mA source current, and features 7.0 ns typical propagation delay (tPHL) and 28 ns typical output disable time (tPLZ). It is used in legacy industrial control backplanes requiring level-shifting and bus contention management.

For engineers reviewing the SN74LS368AML1 datasheet, pinout, applications, or equivalent options, key selection criteria include verified 3-state inverting logic behavior, guaranteed 0.25 V VOL at 12 mA, dual-section enable architecture, and SOIC-16 compatibility with legacy LS-family timing and drive requirements.

Technical Context

The SN74LS368AML1 implements two independent 3-state inverting buffer sections: a 2-bit section (pins 1–2 inputs, 3–4 outputs) and a 4-bit section (pins 5–8 inputs, 9–12 outputs), each controlled by its own active-low enable (E1 on pin 15, E2 on pin 13). Its TTL-compatible input thresholds (VIH = 2.0 V min, VIL = 0.8 V max) and output drive capability (IOL = 24 mA, IOH = −2.6 mA) ensure interoperability with standard LS and ALS logic families.

Propagation delays are asymmetric: tPLH = 12 ns (min), tPHL = 7.0 ns (typ) for LS368A; output enable/disable times (tPZH/tPHZ) are specified under CL = 5.0 pF load. The device draws 21 mA ICC (max) at VCC = 5.25 V and TA = 70°C, and maintains high-impedance isolation with IOZL ≤ −20 μA and IOZH ≤ 20 μA.

Key Specifications

Pinout & Package

SN74LS368AML1 is supplied in a 16-pin SOIC package (Case 751B, D suffix), with 1.27 mm pitch, 10.0 mm × 4.0 mm body, and gull-wing leads. Pin 1 is marked by a beveled corner or notch.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LS368AN and SN74LS368ADR2, the SN74LS368AML1 shares identical logic function, timing, and drive characteristics but differs solely in packaging and shipping format - making it suitable for mid-volume SMT builds requiring rail delivery and traceable lot control without full reel commitment.

Availability

SN74LS368AML1 is available at Aetrix Electronics and suitable for legacy industrial control systems, military avionics upgrades, and test equipment refurbishment requiring stable component supply and long-term obsolescence mitigation.

Supply support for SN74LS368AML1 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 part of onsemi) is a global semiconductor manufacturer specializing in energy-efficient power management, analog, logic, and sensor solutions for automotive, industrial, and cloud infrastructure markets.

The SN74LS368AML1 belongs to the classic 74LS logic family, designed specifically for backward-compatible replacement of obsolete TTL bus interface components in long-lifecycle industrial and defense systems.

FAQ

What is the logic function of the SN74LS368AML1?

The SN74LS368AML1 is a hex 3-state inverting buffer with two independent sections: a 2-bit section (pins 1–2 inputs → 3–4 outputs) and a 4-bit section (pins 5–8 inputs → 9–12 outputs). Each section inverts input signals and presents them at outputs only when its respective active-low enable (E1 on pin 15 or E2 on pin 13) is asserted. When disabled, outputs enter high-impedance state. This behavior is confirmed in the truth table and functional description of the SN74LS368A datasheet.

Does the SN74LS368AML1 support mixed-voltage interfacing?

No, the SN74LS368AML1 is strictly a 5 V TTL device with VCC range 4.75–5.25 V and input thresholds fixed at VIH = 2.0 V min and VIL = 0.8 V max. It does not support 3.3 V or 2.5 V logic levels, and connecting it directly to lower-voltage CMOS or LVTTL sources may cause unreliable switching or excessive input current. For mixed-voltage systems, level-shifting circuitry or a compatible 3.3 V–5 V translator must be used alongside the SN74LS368AML1.

What is the maximum capacitive load the SN74LS368AML1 can drive reliably?

The SN74LS368AML1 is characterized for CL = 45 pF in AC testing (propagation delay) and CL = 5.0 pF for enable/disable timing. While it can drive higher capacitance, sustained loading above 50 pF risks exceeding tPLH/tPHL specifications and increasing ground bounce. For loads >45 pF, design validation is required - including measurement of actual rise/fall times and overshoot under target operating conditions. The SN74LS368AML1 datasheet does not guarantee performance beyond these test conditions.

Can the two enable inputs (E1 and E2) of the SN74LS368AML1 be tied together?

Yes, E1 (pin 15) and E2 (pin 13) may be connected to a common enable signal, effectively converting the SN74LS368AML1 into a unified 6-bit inverting 3-state buffer. This configuration is electrically valid and appears in reference schematics for simplified bus control. However, doing so forfeits the independent section control that enables advanced arbitration schemes - a key differentiator of the SN74LS368AML1 versus single-enable alternatives like SN74LS367A.

Is the SN74LS368AML1 RoHS compliant?

SN74LS368AML1 is a legacy SOIC device manufactured prior to full RoHS enforcement and is not lead-free. Its package contains leaded solder terminations and meets JEDEC J-STD-020 moisture sensitivity level 1 (unlimited floor life), but does not comply with EU RoHS Directive 2011/65/EU or China RoHS II. Customers requiring RoHS-compliant alternatives should evaluate modern replacements such as the 74LVC series, though those require voltage and timing redesign due to different logic families.