This Product Selection Guide contains information to help select products in the Comparators - Linear category on DigiKey.com
Linear comparator products are used to evaluate the relative magnitude of two analog input signals and generate a binary (two-state) output indicating which of the two is larger. Closely related to operational amplifiers in their function, linear comparators are specifically designed to tolerate the open-loop operation and large differential input conditions commonly encountered in analog comparison applications, which can cause standard operational amplifiers to behave in undesirable ways.
SelectionCharacteristics
Type: Indicates the intended function or a defining design feature of a device.
Number of Elements: Indicates the number of instances of a basic function that are incorporated within a device package.
Output Type: Indicates the type of electrical signal the device provides, such as CMOS or TTL.
Voltage - Supply, Single/Dual (±): Indicates the permissible supply voltage range for a device. Devices listed with a range that doesn’t include a +/- term are “single supply” capable, which typically implies a common-mode input range that includes the most-negative supply rail.
Voltage - Input Offset (Max): Characterizes an error term modeled as a DC voltage source in series with one of the comparator inputs.
Current - Input Bias (Max): Maximum current flow through a comparator input. (Ideally zero)
Current - Output (Typ): Typical value for the maximum output current a device can sink and/or source while maintaining output voltage within some specified limit.
Current - Quiescent (Max): Characterizes the amount of supply current required to power a device’s internal functions. Measured with no output load and inputs connected to fixed-voltage signals defined by the manufacturer.
CMRR, PSRR (Typ): Typical common-mode and power supply rejection ratios; higher is generally better.
Propagation Delay (Max): Characterizes the time delay between the assertion of an input and the appearance of a result at a device’s output. Manufacturers’ indicated maximum values shown.
Hysteresis: The typical amount of “extra” signal input voltage that must be applied to change the comparator’s output.
Operating Temperature: Recommended operating temperature, typically given in a range or as a maximum. Exceeding these temperatures may affect performance or damage the device and other system components.
Package / Case: Indicates the type of protective case used on an electronic component to allow easy handling, installation, and protection. This selection was determined to be the closest industry standard applicable to the suppliers device packaging. Typically it is best to check the actual dimensions from the datasheet rather than depend on this terminology when designing your circuit.
Mounting Type: Indicates how the device is attached.
Supplier Device Package: This is what the manufacturer calls the package of this device. They are manufacturer specific. It is typically best to use the actual dimensions from the datasheets rather than use this terminology when designing your circuit.
ProductExamples
| MFR PART # | LM239J |
|---|---|
| DIGIKEY PART # | LM239J-ND |
| MANUFACTURER | Texas Instruments |
| DESCRIPTION | Comparator General Purpose Open-Collector, Rail-to-Rail 14-CDIP |
| DATASHEET | Click Here |
| MFR PART # | LM239QT |
|---|---|
| DIGIKEY PART # | 497-13140-2-ND - Tape & Reel (TR) |
| MANUFACTURER | STMicroelectronics |
| DESCRIPTION | Comparator Differential CMOS, DTL, ECL, MOS, Open-Collector, TTL 16-QFN (3x3) |
| DATASHEET | Click Here |
SchematicSymbol
Schematic symbol courtesy of Scheme-it. Please see their website for more information and symbols.
MediaLinks
Videos
Low Power Single-Dual Comparator Evaluation Boards - NCS22X0A
Operational Amplifiers And Comparators
Comparator
Articles
The Essentials of Analog Voltage Comparators and How to Use Them: Level Detection to Oscillators
Comparator
Product Training Modules
Comparator
Blogs
Comparator
TechForum
Input voltage range and Common mode voltage range for a comparator
Adding Hysteresis on Comparators
Comparator
Maker.IO
Comparator