7400 Series Guide: 74HC75/74LS75 (4-bit bistable latches)

The 74×75 (ex 74LS75) is a chip with four D-latches inside.

Learn how it works and how to use it with this beginner-friendly guide and start using D-latches in your own projects.

What does the 74HC75 / 74LS75 do?

The 74×75 gives you four D-latches that you can use individually. A D-latch is a logic circuit that enables you to store one bit. Among other things, it’s used as the basis for creating flip flops.

How To Use This Chip

The 74HC75 comes in a 16-pin package, and you need to connect it to power before you can use it. Most 7400 ICs support a VCC voltage of 5V. One difference between the HC and LS version of the chip is that the 74HC75 supports 2V to 6V, while the 74LS75 only supports 5V.

The maximum current you can pull out of one output pin of the 74LS75 is 0.4 mA when the pin is high (sourcing) or 8 mA when the pin is low (sinking). This can differ between models, so check the datasheet of your model to verify.

Once you’ve connected it to power, you can use any of the 4-bit bistable latches with complementary outputs inside.

74×75 Pinout

The 74×75 has 16 pins and contains 4-bit bistable latches with complementary outputs laid out as shown in the pinout diagram below:

Pin Name	Pin #	Type	Description
/1Q	1	Output	Output from the first latch (inverted).
1D	2	Input	Input to the first latch.
2D	3	Input	Input to the second latch.
LE34	4	Input	Enable latch 3 and 4.
VCC	5	Power	Positive power supply (VCC). Connect to +5V power.
3D	6	Input	Input to the third latch.
4D	7	Input	Input to the fourth latch.
/4Q	8	Output	Output from the fourth latch(inverted).
4Q	9	Output	Output from the fourth latch.
3Q	10	Output	Output from the third latch.
/3Q	11	Output	Output from the third latch(inverted).
GND	12	Power	Connect to ground (GND).
LE12	13	Input	Enable latch 1 and 2.
/2Q	14	Output	Output from the second latch(inverted).
2Q	15	Output	Output from the second latch.
1Q	16	Output	Output from the first latch.

Alternatives and Equivalents for 74HC75 / 74LS75

There are many versions of the 74×75 chip. They all have the same functionality, but with different specifications such as supported voltages and maximum current output.

Here’s a list of a few equivalents of this chip:

• 74HC75 (High-speed CMOS)
• 74HCT75 (High-speed CMOS, TTL compatible)
• 74LS75 (High-speed TTL)
• 74LVC75 (Low Voltage TTL)
• 74AC75 (Advanced CMOS)
• 74ALS75 (Advanced Low-Power Schottky TTL)
• 74F75 (Very High Speed)
• 74C75 (CMOS, similar to the 4000-series)

Some manufacturers also add a prefix, such as the SN74HC75 and SN74LS75 by Texas Instruments.

Can’t find the 74×75 anywhere? Then try one of the following IC alternatives:

• 74×77 – 4-bit bistable latches.
• 74×100 – Dual 4-bit bistable latches.

If you can’t find the 74×75 IC in your local electronics store, don’t worry, you’ll most likely find it in one of the stores listed on this page of online stores where you’ll find components and tools for all your electronics projects.

Datasheet for the 74LS75 and 74HC75 chips

Download the PDF datasheet for your version of the 74×75 here:

• SN74LS75 (Texas Instruments)
• 74HC75 (Futurlec)
• 74LS75 (Futurlec)