onsemi 74VCX86BQX

Overview

74VCX86BQX from ON Semiconductor is a low-voltage quad 2-input exclusive-OR gate IC designed for logic-level translation and signal routing in mixed-supply systems. It operates from 1.2V to 3.6V V_CC, supports 3.6V-tolerant I/O, delivers ≤3.0 ns propagation delay at 3.3V, and provides ±24 mA drive strength at 3.0V - enabling use in battery-powered portable interfaces and FPGA/CPLD I/O bridging.

For engineers reviewing the 74VCX86BQX datasheet, pinout, applications, or equivalent options, key selection criteria include its DQFN-14 package footprint, power-off high-impedance I/O behavior, rail-to-rail input voltage range (–0.5V to 4.6V), and guaranteed skew ≤0.75 ns across outputs under 1.8V–3.3V operation.

Technical Context

The 74VCX86BQX implements four independent XOR gates using advanced CMOS process technology optimized for speed-power trade-off in sub-3.6V domains. Its I/O structure incorporates dual-threshold input buffers and robust ESD protection (HBM ≥2000V), supporting interoperability between 1.2V, 1.8V, 2.5V, and 3.3V logic families without level shifters.

Each gate exhibits matched t_PHL/t_PLH propagation delays and tightly controlled output-to-output skew (≤0.75 ns at 1.8V), critical for clock-domain crossing and parity generation. The device enters true high-impedance state on all pins when V_CC = 0V, preventing back-driving in hot-swap or partial-power-down configurations.

Key Specifications

Pinout & Package

Packaged in a Pb-free, 14-terminal DQFN (MLP014A) measuring 2.5 × 3.0 mm with 0.5 mm pitch, the 74VCX86BQX uses a depopulated quad flat no-leads layout with exposed die attach pad (DAP) for thermal enhancement. Pin 1 is marked by a quadrant cutout on the top-left corner.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC86APWR and 74AUP2G86DC,125, the 74VCX86BQX uniquely combines 1.2V operation, power-off high-Z, and 3.0 ns speed in a compact DQFN - making it optimal for portable, multi-rail, and hot-pluggable designs where interface robustness and timing margin are critical.

Availability

74VCX86BQX is available at Aetrix Electronics and suitable for PCIe add-in card design, FPGA configuration validation, USB 2.0 transceiver control, and industrial sensor hub logic requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for 74VCX86BQX 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 is a global semiconductor manufacturer specializing in energy-efficient power management, analog, logic, and discrete devices for automotive, industrial, cloud computing, and consumer markets.

The 74VCX family was developed to deliver high-speed, low-voltage logic with enhanced I/O tolerance for mixed-supply system interconnect - targeting portable electronics, FPGA/CPLD I/O expansion, and industrial control interfaces.

FAQ

What is the minimum V_CC required for functional operation of the 74VCX86BQX?

The 74VCX86BQX is fully specified down to 1.2V V_CC, with guaranteed logic operation, propagation delay, and drive capability at that voltage. At 1.2V, output drive is reduced to ±100 µA, sufficient for high-impedance sensing or low-capacitance routing. For full ±24 mA performance, V_CC ≥3.0V is required. Always verify timing margins at the target V_CC using the AC Electrical Characteristics table in the 74VCX86BQX datasheet.

Does the 74VCX86BQX support hot insertion when V_CC is unpowered?

Yes - the 74VCX86BQX features power-off high-impedance inputs and outputs, meaning all pins enter a high-Z state when V_CC = 0V. This prevents back-driving of live buses and eliminates contention during hot-swap events. However, input voltage must remain within absolute maximum rating (–0.5V to 4.6V) regardless of V_CC state. The 74VCX86BQX is commonly used in PCIe hot-plug detection circuits for this reason.

Can the 74VCX86BQX safely interface with 5V logic signals?

No - the 74VCX86BQX has an absolute maximum input voltage of 4.6V and is rated for 3.6V-tolerant operation only. Applying 5V signals risks permanent damage due to overstress of internal clamp diodes and oxide layers. For 5V interface, use a dedicated level translator such as the NTB0102 or SN74AVC4T245. The 74VCX86BQX is intended for 1.2V–3.3V domain bridging, not 5V compatibility.

What is the purpose of the DAP (Die Attach Pad) on the bottom of the 74VCX86BQX DQFN package?

The DAP on the 74VCX86BQX is an electrically isolated thermal pad that improves heat dissipation from the silicon die to the PCB. It must be soldered to a solid copper pour connected to GND for optimal thermal performance, but it is not electrically connected to any internal node. Leaving the DAP unconnected degrades thermal resistance by ~30°C/W and may cause junction temperature exceedance under sustained load. The 74VCX86BQX datasheet specifies recommended land pattern dimensions for reliable DAP soldering.

How does the 74VCX86BQX handle unused inputs?

Unused inputs on the 74VCX86BQX must be terminated to a valid logic level - either V_CC or GND - to prevent floating nodes that cause increased ICC, noise susceptibility, and potential oscillation. The datasheet explicitly states "Floating or unused inputs must be held HIGH or LOW." Leaving inputs unconnected violates recommended operating conditions and may result in erratic behavior or elevated power consumption. This requirement applies equally to all four XOR gates in the 74VCX86BQX.