TI / Nexperia / many · Integrated circuit

74HC86 Quad XOR Gate

Four 2-input XOR gates: a controlled inverter, a one-bit comparator and the core of every adder and CRC.

1.Pinout diagram

Pins 1-7

74HC86

Pins 8-14

Pin detail

Hover a pin for its mappings and gotchas. Click to keep it here.

Fig. 1. 74HC86 Quad XOR Gate, PDIP-14. Hover or tap a signal to light up every pin that carries it.

XOR with one input tied high is an inverter, tied low it is a buffer. That makes it a controlled inverter, which is how you build a selectable-polarity output.
XOR is a one-bit not-equal test, so chaining them gives you a parity generator or a bus comparator.
Same pin arrangement as the 74HC00, 74HC08 and 74HC32.
HC inputs need a level near their own rail. Driving a 5 V part from 3.3 V logic wants the HCT version.

What has to go around the chip before it will run.

Fig. 2. Controlled inverter, drawn from Table 1. Crossing wires are not connected.

Table 1. External parts, and why each one is there.
Part	Between	Why
Wire link	1B (2) to VCC	With one input high the XOR inverts the other. Drive this pin instead and you can switch inversion on and off.
Wire link	4A (12) to GND	An unused input still has to be tied to a rail.
Wire link	4B (13) to GND	The other input of the same unused gate.
100 nF	VCC (14) to GND	Supply decoupling at the pin.

A switchable inverter is most of why an XOR is on a board at all, that and parity. Four of them in a row make a one-instruction NOT across a nibble.

Every pin, alias and mapping. This is the table that prints.

Table 2. Pin assignments.

Complete pin reference for 74HC86 Quad XOR Gate
Pin	Name	Also called	Functions	Notes
1	1A	-	Gate 1 input A
2	1B	-	Gate 1 input B
3	1Y	-	Gate 1 output (XOR)
4	2A	-	Gate 2 input A
5	2B	-	Gate 2 input B
6	2Y	-	Gate 2 output (XOR)
7	GND	-	Ground
8	3Y	-	Gate 3 output (XOR)	Output comes first on this side.
9	3A	-	Gate 3 input A
10	3B	-	Gate 3 input B
11	4Y	-	Gate 4 output (XOR)
12	4A	-	Gate 4 input A
13	4B	-	Gate 4 input B
14	VCC2-6 V	-	Positive supply	100 nF at the pin.

Found a wrong pin? The whole board is one file, data/boards/sn74hc86.json.