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LM393N

Dual comparator, open-collector, 2-36V, GND-sensing, 1.3µs, PDIP-8

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Manufacturer Part：

LM393N

Package：

PDIP-8 (9.81 x 6.35 x 4.57mm, 2.54mm pitch, through-hole)

Brand：

Product Categories：

Integrated Circuits ICs, Microcontrollers (MCU)

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Description

Product Overview

The LM393N from Texas Instruments is a dual differential comparator with open-collector outputs, single-supply operation (2V to 36V), ground-sensing inputs, and low supply current (500µA for both) in a PDIP-8 package.

Key Specifications

Number of Channels	2 (dual)
Supply Voltage Range	2V to 36V (single) or ±1V to ±18V (dual)
Input Offset Voltage	2mV typical, 5mV max @ 25°C
Input Bias Current	25nA typical, 250nA max
Input Offset Current	5nA typical, 50nA max
Common-Mode Input Range	0V to VCC-1.5V (includes ground)
Differential Input Voltage	±36V max
Output Type	Open-collector (NPN, requires pull-up resistor)
Output Sink Current	6mA typical @ VOL=1.5V
Output Saturation Voltage	250mV max @ Isink=4mA
Response Time	1.3µs typical (TTL-level step)
Supply Current (both)	0.4mA typical, 1mA max @ 5V
Operating Temperature	0°C to +70°C
Package	PDIP-8 (9.81 x 6.35mm)

Features

Dual independent differential comparators
Wide supply range: 2V to 36V single supply
Input common-mode range includes ground
Open-collector outputs for wired-OR
Low supply current: 0.4mA for both comparators
Low input offset voltage: 2mV typical
Wide differential input voltage: ±36V
Output compatible with TTL, MOS, and CMOS

Applications

Voltage comparison and threshold detection
Battery monitoring and low-battery detection
Window comparator circuits
Zero-crossing detection
Oscillator and timing circuits

Product Introduction:LM393N Product Introduction

The LM393N from Texas Instruments is a dual differential comparator—the comparator counterpart of the LM358 op-amp. Unlike an op-amp, the LM393 has an open-collector output that can only sink current (pull LOW) and requires an external pull-up resistor to produce a HIGH output. This open-collector architecture enables wired-OR connections: multiple LM393 outputs can share a single pull-up resistor, and any comparator pulling LOW dominates. The input common-mode range includes ground (0V), allowing single-supply operation for comparing signals near ground. The 1.3µs response time is suitable for most DC and low-frequency comparison tasks. The ±36V differential input voltage range allows the two inputs to differ by up to 36V without damage, useful when comparing signals from different voltage domains. The N suffix denotes the PDIP-8 through-hole package.

Working Principle:LM393N Working Principle

The LM393N consists of two independent voltage comparators. Each comparator has an inverting input (-), a non-inverting input (+), and an open-collector output. The comparator continuously compares the voltage at the + input with the voltage at the – input. When V+ > V-, the output transistor is OFF, and the external pull-up resistor pulls the output HIGH. When V+ < V-, the output transistor turns ON, sinking current through the pull-up resistor and pulling the output LOW. There is no negative feedback; the comparator operates open-loop with very high gain, so even a tiny difference between inputs drives the output to one rail or the other. The 2mV typical offset voltage means the switching point may be shifted by up to 5mV from the ideal threshold. The 1.3µs response time includes the internal propagation delay plus the time for the output transistor to switch. In a battery monitor application, the + input connects to a voltage divider from the battery, and the – input connects to a reference voltage (e.g., from a zener or TL431). When the battery voltage drops below the threshold, V+ < V-, and the output goes LOW, triggering an interrupt or LED indicator.

Pin Description:LM393N Pin Definition and Functions

Pin	Name	Type	Description
1	OUT A	Output	Comparator A output (open-collector, requires pull-up)
2	IN- A	Input	Comparator A inverting input
3	IN+ A	Input	Comparator A non-inverting input
4	GND / V-	Power	Ground or negative supply
5	IN+ B	Input	Comparator B non-inverting input
6	IN- B	Input	Comparator B inverting input
7	OUT B	Output	Comparator B output (open-collector, requires pull-up)
8	V+	Power	Positive supply (2V to 36V)

LM393N uses the PDIP-8 package with standard dual comparator pinout: Pin 1 = Output A (open-collector), Pin 2 = Inverting Input A (-), Pin 3 = Non-inverting Input A (+), Pin 4 = GND, Pin 5 = Non-inverting Input B (+), Pin 6 = Inverting Input B (-), Pin 7 = Output B (open-collector), Pin 8 = VCC. The open-collector outputs require external pull-up resistors to VCC or a separate logic supply. This allows output level shifting — the pull-up voltage can differ from VCC. Maximum output sink current is 16mA. Input common-mode range includes ground. Pinout is identical to LM2903, LM393A, and LM2903V comparators.

Application Scenarios:In which products and applications isLM393N used

Battery Monitor: IN+ from battery divider, IN- from TL431 (2.5V ref); output LOW when battery < threshold; LED indicator
Window Comparator: Two comparators with different thresholds; wired-OR outputs; LOW when signal is outside window
Zero Crossing: AC signal through resistor to IN+, IN- at GND; output transitions at each zero crossing
Overcurrent Detect: Current sense amp output to IN+, threshold on IN-; output goes LOW on overcurrent
RC Oscillator: Positive feedback via resistor divider; timing via RC on IN-; free-running square wave output

Alternative Models:What chips are recommended as replacements for LM393N

Model	Manufacturer	Key Difference	Package	Specs
LM393AN	TI	Improved version with lower 2mV max offset voltage for precision threshold detection circuits	DIP-8	1.3µs/2-36V
LM2903N	TI	Automotive-grade -40 to +125C version for under-hood and industrial comparator applications	DIP-8	1.3µs/-40-125C
LM339N	TI	Quad comparator version (4 channels) in DIP-14 for multi-channel threshold detection	DIP-14	1.3µs/4-ch
TLV3202AIDR	TI	High-speed 40ns dual comparator with push-pull output for fast signal detection	SOIC-8	40ns/2.7-5.5V
LTC6702IS8	ADI	Micro-power 18-bit configurable comparator with 200nA supply for battery monitoring	SOIC-8	18-bit/200nA

LM393 is the industry-standard dual voltage comparator with open-drain output and 2-36V supply range. The 1.3µs response time suits general-purpose threshold detection. LM393AN offers lower offset voltage. LM339 provides 4 comparators in DIP-14. For high-speed applications, TLV3202 offers 40ns response with push-pull output at 2.7-5.5V supply.