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LM139A-MIL

SLCS161 – JUNE 2017

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Copyright © 2017, Texas Instruments Incorporated

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. Validate and test

the design implementation to confirm system functionality.

8.1 Application Information

Typically, a comparator compares either a single signal to a reference, or to two differnt signals. Many users take

advantage of the open-drain output to drive the comparison logic output to a logic voltage level to an MCU or

logic device. The wide supply range and high voltage capability makes LM139A-MIL optimal for level shifting to a

higher or lower voltage.

8.2 Typical Application

Figure 7. Single-ended and Differential Comparator Configurations

8.2.1 Design Requirements

For this design example, use the parameters listed in Table 1 as the input parameters.

Table 1. Design Parameters

DESIGN PARAMETER

EXAMPLE VALUE

Input Voltage Range

0 V to Vsup-1.5 V

Supply Voltage

4.5 V to VCC maximum

Logic Supply Voltage

0 V to VCC maximum

Output Current (RPULLUP)

1 µA to 4 mA

Input Overdrive Voltage

100 mV

Reference Voltage

2.5 V

Load Capacitance (CL)

15 pF

8.2.2 Detailed Design Procedure

When using the LM139A-MIL in a general comparator application, determine the following:

•

Input voltage range

•

Minimum overdrive voltage

•

Output and drive current

•

Response time

8.2.2.1 Input Voltage Range

When choosing the input voltage range, the input common-mode voltage range (VICR) must be taken in to

account. If temperature operation is above or below 25°C the VICR can range from 0 V to VCC– 2 V. This limits

the input voltage range to as high as VCC– 2 V and as low as 0 V. Operation outside of this range can yield

incorrect comparisons.