onsemi MC74HC32AF

Overview

MC74HC32AF from ON Semiconductor is a quad 2-input OR gate in SOEIAJ-14 (JEDEC MS-012) package, operating from 2.0 V to 6.0 V, delivering 10 LSTTL load drive capability with propagation delay as low as 13 ns at 6.0 V, used in digital logic interfacing and level translation within industrial control and instrumentation systems.

For engineers reviewing the MC74HC32AF datasheet, pinout, applications, or equivalent options, this device serves as a high-noise-immunity CMOS logic gate compatible with both CMOS and LSTTL outputs (with pullups), supporting wide-voltage operation and Pb-free compliance per JEDEC Std. 7A.

Technical Context

The MC74HC32AF implements four independent OR gates using high-performance silicon-gate CMOS technology, with identical pinout to LS32 and guaranteed operation across –55°C to +125°C. Input thresholds scale with VCC (VIH = 0.7×VCC min, VIL = 0.3×VCC max), enabling robust voltage-level interoperability.

Each gate exhibits matched AC characteristics: tPLH/tPHL ≤19 ns at 4.5 V and ≤13 ns at 6.0 V (CL = 50 pF); output transition times (tTLH/tTHL) match propagation delays closely, ensuring predictable timing margins in synchronous logic paths.

Key Specifications

Pinout & Package

MC74HC32AF is housed in a 14-lead SOEIAJ (JEDEC MS-012) surface-mount package, 8.2 mm × 5.45 mm footprint, 1.27 mm lead pitch, Pb-free (G suffix), rated for reflow soldering per J-STD-020.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar quad 2-input OR gate applications.

Compared with MC74HC32AF, SN74HC32DR offers identical logic behavior but different packaging and RoHS status, while 74VHC32M trades extended voltage/temperature range for speed and lower static current - making MC74HC32AF optimal for ruggedized, wide-supply industrial designs.

Availability

MC74HC32AF is available at Aetrix Electronics and suitable for industrial PLC I/O expansion, automotive body control modules, and medical instrument power sequencing requiring stable component supply, long-term lifecycle support, and RoHS-compliant sourcing.

Supply support for MC74HC32AF 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 supplier specializing in energy-efficient electronics, with leadership in automotive, industrial, cloud power, and sensing technologies.

The MC74HC32AF belongs to the 74HC high-speed CMOS logic family, designed for robust, low-power digital interfacing in harsh environments where reliability, wide voltage operation, and temperature resilience are critical.

FAQ

What is the maximum supply voltage rating for MC74HC32AF?

The MC74HC32AF has an absolute maximum DC supply voltage (VCC) rating of +7.0 V, but its recommended operating range is 2.0 V to 6.0 V. Operating continuously at 7.0 V exceeds specification limits and risks permanent damage; sustained use at 6.0 V is fully characterized and supported across the full temperature range.

Does MC74HC32AF support direct interface with LSTTL outputs without pull-up resistors?

No - MC74HC32AF inputs are compatible with standard CMOS outputs natively, but require external pull-up resistors to interface reliably with LSTTL outputs. This is because LSTTL high-level output voltage (typically 2.4 V min) falls below the MC74HC32AF's VIH threshold at VCC = 5 V (3.15 V min), necessitating pull-ups to ensure valid logic-high recognition.

What is the input capacitance of MC74HC32AF and how does it affect high-frequency operation?

The MC74HC32AF has a maximum input capacitance (Cin) of 10 pF per pin. At 10 MHz, this contributes ~1.6 mA of capacitive current per toggling input (I = 2πfCV), which remains well within the ±20 µA input leakage limit and does not degrade timing - however, above 50 MHz, trace impedance matching and layout parasitics dominate timing behavior more than Cin alone.

Is MC74HC32AF pin-compatible with the obsolete 74LS32?

Yes - the MC74HC32AF is explicitly designed with identical pinout to the 74LS32, including VCC on pin 14 and GND on pin 7. This allows direct PCB replacement in legacy TTL designs, provided supply voltage is adjusted to 2.0–6.0 V and input drive requirements (e.g., LSTTL pull-ups) are verified per the datasheet.

How does the MC74HC32AF handle unused inputs and outputs?

Unused inputs on the MC74HC32AF must be tied to a valid logic level - either VCC or GND - to prevent floating states that cause excessive ICC and potential oscillation. Unused outputs must be left open; connecting them to VCC or GND violates absolute maximum ratings and may damage the output stage due to contention current exceeding ±25 mA.