7400 Series Guide: 74LS37 (2-input NAND gates)

The 74×37 (ex 74LS37) is a chip with four basic NAND gates with buffered output. Buffered outputs means it can provide more current than a standard NAND gate in the 7400 series.

In this guide, you’ll learn the things you need to know about this chip in order to use NAND gates in your own projects.

What does the 74LS37 do?

The 74×37 gives you four basic NAND gates with buffered output that you can use individually. A NAND gate is a logic gate that outputs 0 (LOW) only if all of its inputs are 1 (HIGH). In the truth table below, you can see what the output will be for any given input:

How To Use This Chip

The 74LS37 comes in a 14-pin package, and you need to connect it to power before you can use it. Like most 7400 ICs, it supports a VCC voltage of 5V.

The maximum current you can pull out of one output pin of the 74×37 is 15 mA (SN7437) or 8 mA (SN74LS37) when the pin is low (sinking), but only 0.8/0.4 mA when the pin is high (sourcing). 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 four basic NAND gates with buffered output inside.

74LS37 Pinout

The 74×37 has 14 pins and contains four basic NAND gates with buffered output laid out as shown in the pinout diagram below:

Pin #	Type	Description
1	Input	Input to the first NAND gate.
2	Input	Input to the first NAND gate.
3	Output	Output from the first NAND gate.
4	Input	Input to the second NAND gate.
5	Input	Input to the second NAND gate.
6	Output	Output from the second NAND gate.
7	Power	Connect to ground (GND).
8	Output	Output from the third NAND gate.
9	Input	Input to the third NAND gate.
10	Input	Input to the third NAND gate.
11	Output	Output from the fourth NAND gate.
12	Input	Input to the fourth NAND gate.
13	Input	Input to the fourth NAND gate.
14	Power	Positive power supply (VCC). Connect to +5V power.

Alternatives and Equivalents for 74LS37

There are many versions of the 74×37 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:

• 74HC37 (High-speed CMOS)
• 74HCT37 (High-speed CMOS, TTL compatible)
• 74LS37 (High-speed TTL)
• 74LVC37 (Low Voltage TTL)
• 74AC37 (Advanced CMOS)
• 74ALS37 (Advanced Low-Power Schottky TTL)
• 74F37 (Very High Speed)
• 74C37 (CMOS, similar to the 4000-series)
• 7437 and 74S37

Some manufacturers also add a prefix, such as the and SN74LS37 by Texas Instruments.

Can’t find the 74×37 anywhere? Then try one of the following IC alternatives:

• 74×00 – Quad 2-input NAND gates.
• 74×01 – Quad 2-input NAND gates (with open-collector outputs).
• 74×03 – Quad 2-input NAND gates (with open-collector outputs).
• 74×24 – Quad 2-input NAND gates (with Schmitt-trigger inputs).
• 74×26 – Quad 2-input NAND gates (with open-collector outputs that support 15V).
• 74×38 – Quad 2-input NAND gates with buffered outputs.
• 74×132 – Quad 2-input NAND gates (with Schmitt-trigger inputs).
• CD4011 – Quad 2-input NAND gates.
• CD4093 – Quad 2-input NAND gates (with Schmitt-trigger inputs).

If you can’t find the 74×37 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 74LS37 chip

Download the PDF datasheet for your version of the 74×37 here:

• SN74LS37 (Texas Instruments)
• 74LS37 (Futurlec)