The 74×17 (ex 74HC17) is a chip that comes with six open-collector buffers. An open collector output makes it easy to interface with chips of different logic levels, although swapping it with a standard buffer chip isn’t straightforward.
Learn how it works and how to use it with this beginner-friendly guide and start using open-collector buffers in your projects.
What does the 74HC17 / 74LS17 do?
The 74×17 gives you six open-collector buffers that you can use individually. A buffer is a gate that outputs the same as the input. It’s often used to get more current (and/or) voltage from an output.
How To Use This Chip
The 7417 comes in a 14-pin package, and you need to connect its power pins before you can use it. It supports a VCC voltage of 5V.
This chip uses open-collector outputs which means you can only sink current, not source it.
The output of each gate in the 7417 can sink around 30-50 milliamps when it’s powered with 5 volts.
74×17 Pinout
The 74×17 has 14 pins and contains six open-collector buffers laid out as shown in the pinout diagram below:
| Pin Name | Pin # | Type | Description |
|---|---|---|---|
| 1A | 1 | Input | Input to the first buffer. |
| 1Y | 2 | Output | Open-collector output from the first buffer. |
| 2A | 3 | Input | Input to the second buffer. |
| 2Y | 4 | Output | Open-collector output from the second buffer. |
| 3A | 5 | Input | Input to the third buffer. |
| 3Y | 6 | Output | Open-collector output from the third buffer. |
| GND | 7 | Power | Connect to ground (GND). |
| 4Y | 8 | Output | Open-collector output from the fourth buffer. |
| 4A | 9 | Input | Input to the fourth buffer. |
| 5Y | 10 | Output | Open-collector output from the fifth buffer. |
| 5A | 11 | Input | Input to the fifth buffer. |
| 6Y | 12 | Output | Open-collector output from the sixth buffer. |
| 6A | 13 | Input | Input to the sixth buffer. |
| VCC | 14 | Power | Positive power supply (VCC). Connect to +5V power. |
Alternatives and Equivalents for 7417
There are only a few versions of the 7417 chip.
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The three versions I’ve been able to locate are DM7417 by Fairchild Semiconductor (now Onsemi), the SN7417 by Texas Instruments, and the 7417PC by National Semiconductor. They’re pretty much the same.
It is an obsolete chip, but can still be found.
Datasheet for the 7417 chip
Download the PDF datasheet for your version of the 74×17 here:
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