LM139-N, LM239-N, LM2901-N, LM3302-N, LM339-N

SNOSBJ3E – NOVEMBER 1999 – REVISED DECEMBER 2014

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8 Application and Implementation

NOTE

Information in the following applications sections is not part of the TI component

specification, and TI does not warrant its accuracy or completeness. TI’s customers are

responsible for determining suitability of components for their purposes. Customers should

validate and test their design implementation to confirm system functionality.

8.1 Application Information

The LM139-N is specified for operation from 2.0 V to 36 V (±1V to ±18V) over the temperature range of –55°C to

125°C. While it may seem like a comparator has a well-defined and somewhat limited functionality as a '1-bit

ADC', a comparator is a versatile component which can be used for many functions.

Refer to AN-74 LM139/LM239/LM339 A Quad of Independently Functioning Comparators (SNOA654) for

additional application information on use of the LM139-N.

8.2 Typical Applications

8.2.1 Basic Comparator

Figure 11. Basic Comparator Schematic

8.2.1.1 Design Requirements

The basic usage of a comparator is to indicate when a specific analog signal has exceeded some predefined

threshold. In this application, the negative input is tied to a reference voltage, and the positive input is connected

to the input signal. The output is pulled up with a resistor to the logic supply voltage, V+.

For an example application, the supply voltage is 5 V. The input signal varies between 1 V and 3 V, and we want

8.2.1.2 Application Curve

Figure 12. Basic Comparator Response

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