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IC Pinouts / LM339

LM339 Pinout

LM339 Quad Comparator · Quad voltage comparator with open-collector outputs, single-supply capable.

DIP-14 Comparator 14 pins No backend · 100% client-side
OUT2 1
OUT1 2
VCC(V+) 3
IN1− 4
IN1+ 5
IN2− 6
IN2+ 7
LM339 DIP-14
14 OUT3
13 OUT4
12 GND(V−)
11 IN4+
10 IN4−
9 IN3+
8 IN3−
PowerGNDInputOutputI/OControl
PinNameTypeFunction
1 OUT2 Output Comparator 2 output (open-collector)
2 OUT1 Output Comparator 1 output (open-collector)
3 VCC · V+ Power Positive supply (2–36V)
4 IN1− Input Comparator 1 inverting input
5 IN1+ Input Comparator 1 non-inverting input
6 IN2− Input Comparator 2 inverting input
7 IN2+ Input Comparator 2 non-inverting input
8 IN3− Input Comparator 3 inverting input
9 IN3+ Input Comparator 3 non-inverting input
10 IN4− Input Comparator 4 inverting input
11 IN4+ Input Comparator 4 non-inverting input
12 GND · V− GND Negative supply / ground
13 OUT4 Output Comparator 4 output (open-collector)
14 OUT3 Output Comparator 3 output (open-collector)
How to · reading it

How to read the LM339 pinout

  1. 01

    Find pin 1

    One end of the chip has a half-circle notch or a dot; with the notch facing up, the top-left pin is pin 1.

  2. 02

    Count counter-clockwise

    Count counter-clockwise from pin 1: go down the left side first, then up the right side from the bottom.

  3. 03

    Check the table below

    Look up each pin's function by number in the table below; power/ground are color-coded, and alternate-function signals are in parentheses.

FAQ

Frequently asked questions

Why is my LM339 output stuck low / not toggling?

The outputs are open-collector — they can only pull low. You must add a pull-up resistor (typically 1–10kΩ) from each used output to your logic supply, otherwise the high state floats.

Can I swap an LM339 for an LM324?

No — different pinout (V+ on pin 3 / GND on pin 12 for the 339, vs pin 4 / pin 11 for the 324) and the 339 has open-collector outputs, not push-pull. They are not interchangeable.

How do I add hysteresis?

Add positive feedback from the output (through the pull-up) back to the non-inverting input. This creates a Schmitt-trigger threshold band that prevents chatter on slow or noisy inputs.

Data source

Pinout data comes from TI LM339 datasheet (standard DIP-14 numbering). Refer to the actual device datasheet as authoritative for the pinout.

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