Texas Instruments CD74HC4049NSR

Overview

CD74HC4049NSR from Texas Instruments is a hex inverting buffer IC designed for high-to-low voltage level translation, supporting up to 15 V input while operating from a 2–6 V supply. It delivers 6 ns typical propagation delay at 5 V/15 pF, operates across –55°C to 125°C, and provides 10 LSTTL fanout with CMOS-compatible inputs and outputs. It is used in industrial interface circuits where legacy 12 V or 15 V logic must drive 3.3 V or 5 V microcontrollers.

For engineers reviewing the CD74HC4049NSR datasheet, CD74HC4049NSR pinout, CD74HC4049NSR application, or CD74HC4049NSR equivalent, key selection criteria include its 15 V tolerant inputs, inverting logic function, SOP-16 package thermal performance (θ_JA = 64°C/W), wide temperature range, and compatibility with HC-series timing and noise immunity specs.

Technical Context

The CD74HC4049NSR implements six independent inverting buffers using high-speed silicon-gate CMOS technology with modified input protection that enables safe operation with input voltages up to 15 V - exceeding V_CC - while output levels remain rail-to-rail within the V_CC range (0 V to V_CC). This architecture supports true bidirectional level shifting without external components.

It features balanced t_PLH/t_PHL and t_TLH/t_THL transition times, ensuring minimal duty-cycle distortion in clock or data paths. Its 30% noise immunity (NIL/NIL = 30% of V_CC) and low quiescent current (≤40 µA over full temperature range) make it suitable for noise-prone industrial control and mixed-voltage sensor interfacing.

Key Specifications

Pinout & Package

SOP-16 (Small Outline Package, 16-pin) with standard JEDEC MO-153 footprint; 1.27 mm pitch; body size 10.3 mm × 5.3 mm; moisture sensitivity level (MSL) 1, peak reflow 260°C.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVX4049PW and CD74HC4050NSR, the CD74HC4049NSR uniquely combines 15 V input tolerance with inverting logic in SOP-16, making it irreplaceable for legacy-to-modern voltage translation where signal inversion is acceptable or required.

Availability

CD74HC4049NSR is available at Aetrix Electronics and suitable for industrial PLC I/O modules, automotive body control units, and military data acquisition systems requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for CD74HC4049NSR 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

Texas Instruments is a global semiconductor company headquartered in Dallas, Texas, delivering analog and embedded processing solutions for industrial, automotive, and communications markets.

The CD74HC4049NSR belongs to TI's High-Speed CMOS Logic family, engineered for robust voltage translation and noise-immune digital interfacing in harsh, mixed-supply environments.

FAQ

What is the maximum input voltage rating for CD74HC4049NSR?

The CD74HC4049NSR supports an absolute maximum input voltage of 15 V, as specified in its DC input voltage range (–0.5 V to 15 V). This allows direct connection to 12 V logic or industrial sensors without external clamping diodes or resistive dividers. Operation above 15 V risks permanent damage, and the device must be powered within its 2–6 V V_CC range during such input conditions. The CD74HC4049NSR input protection structure is specifically designed for this overvoltage tolerance.

Can CD74HC4049NSR operate with a 3.3 V supply while accepting 12 V inputs?

Yes, the CD74HC4049NSR can operate with a 3.3 V V_CC supply while reliably accepting 12 V inputs on its A pins. Its modified input protection enables this high-to-low level translation function without damage or latch-up. Output levels will swing between 0 V and 3.3 V, maintaining full CMOS logic compatibility with downstream 3.3 V devices. The CD74HC4049NSR datasheet explicitly confirms this capability under "Description" and "Absolute Maximum Ratings".

Is CD74HC4049NSR pin-compatible with CD74HC4050NSR?

Yes, CD74HC4049NSR and CD74HC4050NSR share identical SOP-16 pinouts, package dimensions, and thermal characteristics. The only functional difference is logic polarity: CD74HC4049NSR provides inverting buffers, while CD74HC4050NSR provides non-inverting buffers. Both support the same 15 V input tolerance and 2–6 V supply range. This makes CD74HC4049NSR and CD74HC4050NSR drop-in replacements where signal inversion is either required or acceptable.

What is the thermal resistance (θ_JA) of CD74HC4049NSR in SOP package?

The junction-to-ambient thermal resistance (θ_JA) for CD74HC4049NSR in the SOP (NS) package is 64°C/W, as documented in the "Thermal Information" section of the datasheet. This value applies under standard JEDEC test conditions (single-layer board, no copper pour). Designers should use this parameter to estimate junction temperature rise under expected power dissipation, especially in high-density or thermally constrained industrial layouts where the CD74HC4049NSR may operate continuously at elevated ambient temperatures.

Does CD74HC4049NSR require external pull-up or pull-down resistors on unused inputs?

No, CD74HC4049NSR does not require external pull-up or pull-down resistors on unused inputs. Its CMOS inputs have high impedance and negligible leakage (±1 µA max), but floating inputs can cause increased supply current and unpredictable output states due to noise coupling. TI recommends connecting unused inputs to V_CC or GND - not leaving them open - to ensure stable operation and minimize power consumption. This guidance applies equally to all configurations of the CD74HC4049NSR in real-world PCB designs.