SN74AC244 Equivalent or Compatible Octal Buffer / Driver Chips

If you are planning to build your first buffer project, then one excellent chip currently available is the SN74AHC541N IC. It is extremely simple to build this on a prototyping board and provides hours of fun for the electronics hobbyist.

This IC is an advanced high-speed CMOS chip consisting of eight non-inverting buffers that are all pointing in the same direction. When all the buffers are pointing in the same direction, it can eliminate much confusion, and make board construction easier. The Output Enable (OE) control is a two-input AND gate with active-low function.

Output Enable

The electronics industry supplies a wide range of octal buffer chips and some of them use a different pinout and buffer arrangement. Not all use the same logic for the OE control signal.

As shown in the diagram above, pins 1 and pin 19 of the SN74AC244 chip are active low; however, there are many other octal buffer chips where the pins are complementary, which is when pin 1 will be active low whilst pin 19 will be active high. Once you know this little difference, it is not a problem because you simply build a circuit where pin 1 ties to ground and pin 19 ties to Vcc.

Operating Voltage

Many ICs based on CMOS technology will operate on 3.3 V. The 74 Family Series Meaning of Lettering article provides information about suitable ICs. Here is a short list of the ones currently found today.

• AC: Advanced CMOS
• AHC: Advanced High speed CMOS
• AHCT: Advanced High speed CMOS TTL Compatible
• HC: High speed CMOS
• HCT: High speed CMOS TTL Compatible.

Inverting / Non-Inverting

Some octal buffer chips have inverting buffers whilst others have non-inverting buffers. For compatibility with the SN74AC244, you need non-inverting buffers.

Compatible IC

Ideally you need a chip that can operate at 3.3 V and provide CMOS level I/O, has non-inverting buffers, both control pins should be active low, and be using the same pin arrangement. Below are listed some chips that are compatible and currently available online on Google.

• 74AC244PC
• RS: 1014026

• MC74HC244ANG
• Farnell: 9665897

• CD74AC244E
• Farnell: 1105998

• SN74HC244
• Farnell: 9591281

• SN74AHC541N
• Farnell: 4586086

• SN74HC244
• eBay

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