onsemi MM74HC4049N

Overview

MM74HC4049N from Fairchild Semiconductor is a hex inverting logic level down converter IC designed to translate high-voltage CMOS logic (up to 15V) to lower-voltage logic domains (2–6V supply), with 6 independent inverting buffer channels, ±25 mA output drive per pin, and 8 ns typical propagation delay at 4.5V. It enables interface between legacy 12V/15V logic and modern 5V or 3.3V microcontrollers in industrial control backplanes.

For engineers reviewing the MM74HC4049N datasheet, pinout, applications, or equivalent options, key selection criteria include input voltage tolerance up to 15V, VCC-independent input clamping, guaranteed 3.98V VOH at 4.5V/4mA, −40°C to +85°C operating range, and PDIP-16 package compatibility with through-hole prototyping and legacy PCBs.

Technical Context

The MM74HC4049N implements six independent CMOS inverting buffers with modified input protection-no V_CC-tied diode-enabling safe operation with inputs up to 15V while powered from as low as 2V. Its input stage uses a zener-clamped structure for bidirectional ESD protection and rail-to-rail input voltage support beyond V_CC.

Each channel delivers rail-aligned output swing (VOH ≥ V_CC−0.2V, VOL ≤ 0.4V at full load), supports fanout of 10 LS-TTL loads, and maintains timing integrity with t_PLH/t_PHL ≤ 17 ns at 4.5V/50 pF. Propagation delay scales predictably across 2–6V V_CC, enabling stable operation in mixed-supply systems.

Key Specifications

Pinout & Package

MM74HC4049N is housed in a 16-lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300" wide, with 0.100" lead pitch and through-hole mounting. The package provides mechanical robustness and thermal dissipation suitable for manual assembly and reflow-compatible wave soldering.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar logic level down conversion applications.

Compared with CD4049BE and SN74LVX4049N, the MM74HC4049N uniquely balances 15V input tolerance, 17 ns timing at 4.5V, and PDIP-16 compatibility-making it the only option for retrofitting high-voltage industrial logic into modern 5V control systems without layout changes.

Availability

MM74HC4049N is available at Aetrix Electronics and suitable for industrial PLC backplanes, legacy sensor interface modules, and motor control logic isolation requiring stable component supply, long-term obsolescence management, and through-hole manufacturing compatibility.

Supply support for MM74HC4049N 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

Fairchild Semiconductor was a leading designer of high-performance analog and mixed-signal ICs, acquired by ON Semiconductor in 2016; its legacy logic portfolio remains widely deployed in industrial and automotive systems.

The MM74HC4049N belongs to Fairchild's 74HC logic family, engineered specifically for robust level translation in mixed-voltage systems where legacy high-voltage logic must interoperate with modern low-voltage controllers.

FAQ

What is the maximum input voltage the MM74HC4049N can safely accept?

The MM74HC4049N supports DC input voltages from −1.5V to +18V, with guaranteed operation up to +15V even when powered from as low as 2V. This is enabled by its zener-clamped input structure and absence of V_CC-tied protection diodes. The MM74HC4049N thus tolerates 12V and 15V logic signals directly-critical for interfacing with legacy industrial sensors and controllers without external attenuation.

Can the MM74HC4049N operate from a 3.3V supply while translating 12V inputs?

Yes, the MM74HC4049N operates reliably from 2V to 6V V_CC, including 3.3V. When V_CC = 3.3V, it accepts 12V inputs safely and produces 3.3V-compatible outputs with VOL ≤ 0.33V and VOH ≥ 3.1V at 4mA load. The MM74HC4049N maintains this behavior across −40°C to +85°C, making it suitable for mixed-supply embedded gateways.

Is the MM74HC4049N pin-compatible with the CD4049BC?

Yes, the MM74HC4049N is pin and functionally compatible with the CD4049BC, sharing identical PDIP-16 pinout and inverting buffer functionality. However, the MM74HC4049N offers significantly faster propagation (17 ns vs. 50+ ns), lower quiescent current (20 µA vs. ~100 µA), and superior 15V input tolerance at low V_CC. The MM74HC4049N serves as a drop-in upgrade where speed and power matter.

Does the MM74HC4049N require external pull-up or pull-down resistors?

No, the MM74HC4049N does not require external pull-up or pull-down resistors on its inputs or outputs under normal operation. Its CMOS inputs have negligible leakage (±0.1 µA at 6V), and outputs actively drive both logic states. External resistors are only needed if specific bus-termination or fail-safe biasing is required-functions not inherent to the MM74HC4049N's core level translation role.

What is the thermal derating behavior of the MM74HC4049N in the PDIP package?

The MM74HC4049N in the N16E (PDIP) package has a power dissipation derating factor of −12 mW/°C above 65°C, with a maximum rated PD of 500 mW at ≤65°C ambient. At 85°C ambient, usable power drops to 260 mW. This derating ensures reliability in enclosed industrial enclosures; heatsinking is unnecessary for typical logic-level loads drawing <10 mA per channel.