74HCT08D vs 74HCT123D-Q100J

The 74HCT08D is a quad 2-input AND gate, providing four independent logic gates in a single package. The 74HCT123D-Q100J is a dual retriggerable monostable multivibrator with clear and trigger inputs, used for pulse generation and timing applications. They serve fundamentally different logic and timing functions and are not functionally interchangeable.

No. The 74HCT08D is typically supplied in a 14-pin SOIC package with a standard quad-gate pinout, while the 74HCT123D-Q100J is supplied in a 16-pin SOIC package with a different pin configuration to accommodate its dual monostable functions, including timing and trigger pins. They cannot be directly substituted on the same PCB footprint.

Yes. Both the 74HCT08D and the 74HCT123D-Q100J are HCT-family devices designed for a nominal 5 V supply, with a specified operating supply voltage range of 4.5 V to 5.5 V. This makes them compatible with TTL logic levels while retaining CMOS input characteristics.

The 74HCT08D has a typical propagation delay of approximately 10 ns to 15 ns depending on the manufacturer and load conditions. The 74HCT123D-Q100J has a propagation delay from trigger input to output of approximately 20 ns to 30 ns typical, plus the programmed output pulse width determined by the external timing components. The AND gate is significantly faster in signal propagation.

The 74HCT123D-Q100J carries the Q100 suffix, indicating it is qualified to the AEC-Q100 standard for automotive-grade integrated circuits. The 74HCT08D, as a standard logic device without the Q100 designation, is not necessarily AEC-Q100 qualified. Designers requiring automotive qualification should verify the specific ordering part number and manufacturer documentation.

No. The 74HCT08D is a combinational logic AND gate and has no internal timing or retriggerable monostable circuitry. Generating a controlled pulse width requires external RC timing components and additional logic, whereas the 74HCT123D-Q100J integrates the monostable function with programmable pulse width via external resistors and capacitors.

Both devices are HCT-family logic ICs and typically provide symmetrical CMOS output drive. Standard datasheet specifications for both the 74HCT08D and 74HCT123D-Q100J list output current of ±4 mA at 5 V, which is sufficient for driving standard TTL loads and low-power CMOS inputs. Exact drive strength should be confirmed from the specific manufacturer datasheet.

No. Because they differ in logic function, package pin count, pinout, and internal circuitry, the 74HCT08D and 74HCT123D-Q100J are not interchangeable. A design requiring a quad AND gate cannot substitute a dual monostable multivibrator, and vice versa, without significant circuit redesign and validation against manufacturer documentation.