onsemi MC74HCT86ADG

Overview

MC74HCT86ADG from onsemi is a quad 2-input XOR gate in SOIC-14 package, operating at 4.5–5.5 V supply, with TTL-compatible inputs, 18 ns typical propagation delay at 5 V, and ±4 mA output drive capability. It performs logic-level exclusive-OR functions in digital control, status monitoring, and error-detection circuits.

For engineers reviewing the MC74HCT86ADG datasheet, pinout, applications, or equivalent options, key selection factors include its 5 V TTL-compatible input thresholds, guaranteed fan-out of 10 LS-TTL loads, industrial temperature range (−40°C to +85°C), and SOIC-14 footprint compatibility with legacy HCT logic families.

Technical Context

The MC74HCT86ADG implements four independent XOR logic gates using silicon-gate CMOS technology, ensuring compatibility with both TTL and CMOS logic levels. Its input structure accepts standard TTL voltage thresholds (V_IL ≤ 0.8 V, V_IH ≥ 2.0 V) while drawing negligible static current (I_CC = 4 µA max).

Each gate delivers rail-to-rail CMOS output swing with symmetrical rise/fall times (t_r/t_f = 15 ns typ at 5 V, C_L = 50 pF), and supports direct interfacing to LS-TTL, HCT, and other 5 V logic families without level-shifting.

Key Specifications

Pinout & Package

MC74HCT86ADG is housed in a 14-pin SOIC (Small Outline Integrated Circuit) package with 1.27 mm pitch, JEDEC MS-012AC compliant, and rated for surface-mount reflow assembly.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar XOR gate applications.

Compared with SN74HCT86DR and 74VHC86M, the MC74HCT86ADG provides guaranteed TTL input compatibility and industrial temperature qualification out-of-the-box, making it optimal for legacy system upgrades and mixed-signal industrial controllers where input threshold margin is non-negotiable.

Availability

MC74HCT86ADG is available at Aetrix Electronics and suitable for industrial control panels, automotive body electronics, and medical diagnostic instrument design requiring stable component supply and long-term manufacturability.

Supply support for MC74HCT86ADG 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

onsemi is a global semiconductor leader delivering energy-efficient, intelligent power and sensing solutions for automotive, industrial, cloud, medical, and IoT applications.

The MC74HCT86ADG belongs to onsemi's High-Speed CMOS (HCT) logic family, designed specifically for seamless interoperability with legacy TTL systems while delivering CMOS power efficiency and noise immunity.

FAQ

What logic family does the MC74HCT86ADG belong to, and how does it differ from standard HCMOS?

The MC74HCT86ADG belongs to the HCT (High-speed CMOS with TTL-compatible inputs) logic family. Unlike standard HCMOS (e.g., 74HC86), it features input thresholds matched to TTL levels (V_IL ≤ 0.8 V, V_IH ≥ 2.0 V), enabling direct interface with older 74LS and 74ALS devices without level shifters. The MC74HCT86ADG retains CMOS advantages: low power consumption, high noise immunity, and rail-to-rail outputs - all while maintaining full backward compatibility with TTL source logic.

Can the MC74HCT86ADG operate reliably at 4.5 V supply, and what is its minimum guaranteed output drive at that voltage?

Yes, the MC74HCT86ADG is fully specified from 4.5 V to 5.5 V. At V_CC = 4.5 V, its guaranteed output drive remains ±4 mA (I_OH/I_OL), supporting the same 10 LS-TTL load fan-out as at 5 V. Propagation delay increases slightly to 22 ns typical, but all AC/DC parameters remain within datasheet limits - making it suitable for designs with marginal 5 V rails or wide-input-voltage DC-DC outputs.

Is the MC74HCT86ADG pin-compatible with the obsolete 74LS86, and what design considerations ensure drop-in replacement?

Yes, the MC74HCT86ADG is pin-compatible with the 74LS86 in SOIC-14 packages and shares identical pinout and logic function. To ensure drop-in replacement, verify that the existing board uses 5 V supply and that output loading does not exceed ±4 mA per gate. No changes to PCB layout or pull-up/pull-down resistors are needed - the MC74HCT86ADG's TTL-compatible inputs accept the same voltage levels as the 74LS86, and its CMOS outputs drive equivalent loads with lower power dissipation.

What is the maximum clock frequency supported by the MC74HCT86ADG in a toggle configuration?

The MC74HCT86ADG is a combinational logic device, not a sequential one, so it has no inherent clock input or maximum toggle frequency rating. However, in a feedback loop (e.g., XOR-based oscillator), its 18 ns typical propagation delay sets an upper practical limit of ~25 MHz for stable oscillation under standard load conditions (C_L = 50 pF). For synchronous edge-triggered use, setup/hold timing depends on upstream driver characteristics - the MC74HCT86ADG itself imposes no clock domain constraints.

Does the MC74HCT86ADG require external pull-up resistors on unused inputs, and why?

No, external pull-up resistors are not required on unused inputs of the MC74HCT86ADG. Its CMOS input structure has extremely high impedance (>10¹² Ω), and floating inputs are electrically unstable - but the recommended practice is to tie each unused input to either V_CC or GND (not left open), to prevent noise-induced oscillation and excess current draw. This is a design best practice, not a requirement for MC74HCT86ADG functionality - the part itself draws negligible current regardless, but system reliability mandates proper termination.