LM393 Pinout
LM393 Dual Comparator · Dual voltage comparator; open-drain output, requires a pull-up resistor.
| Pin | Name | Type | Function |
|---|---|---|---|
| 1 | OUT1 | Output | Comparator A output (open-drain, needs pull-up) |
| 2 | IN1− | Input | Comparator A inverting input |
| 3 | IN1+ | Input | Comparator A non-inverting input |
| 4 | GND · V− | GND | Negative supply / ground |
| 5 | IN2+ | Input | Comparator B non-inverting input |
| 6 | IN2− | Input | Comparator B inverting input |
| 7 | OUT2 | Output | Comparator B output (open-drain) |
| 8 | VCC · V+ | Power | Positive supply (2–36V) |
How to read the LM393 pinout
- 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.
- 02
Count counter-clockwise
Count counter-clockwise from pin 1: go down the left side first, then up the right side from the bottom.
- 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.
Frequently asked questions
Why does the output need a pull-up resistor?
The LM393 has an open-drain output that can only pull low, not high. You need a pull-up resistor (commonly 10kΩ) between OUT and VCC to get a high level.
Do the LM393 and LM358 have the same pinout?
The pinout is identical (both 8-pin dual channel). But the 393 is a comparator (open-drain, fast) and the 358 is an op-amp (push-pull, linear); they serve different purposes.
Pinout data comes from TI LM393 datasheet (standard DIP-8 numbering). Refer to the actual device datasheet as authoritative for the pinout.