80- A

µ

Current Regulator

80 µA

60 µA

10 µA

VCC

10 µA

OUT

GND

IN+

IN−

Epi-FET

Diodes

Resistors

Transistors

COMPONENT COUNT

1

2

2

30

7

LM139A-MIL

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SLCS161 – JUNE 2017

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7 Detailed Description

7.1 Overview

The LM139A-MIL is a quad comparator with the ability to operate up to an absolute maximum of 36 V on the

supply pin. This standard device has proven ubiquity and versatility across a wide range of applications. This is

due to very wide supply voltages range (2 V up to 32 V), low Iq, and fast response of the device.

The open-drain output allows the user to configure the output logic low voltage (VOL) and allows the comparator

to be used in AND functionality.

7.2 Functional Block Diagram

Figure 6. Schematic (Each Comparator)

7.3 Feature Description

The comparator consists of a PNP Darlington pair input, allowing the device to operate with very high gain and

fast response with minimal input bias current. The input Darlington pair creates a limit on the input common-

mode voltage capability, allowing the comparator to accurately function from ground to (VCC – 1.5 V) differential

input. Allow for (VCC – 2 V) at cold temperature.

The output consists of an open-collector NPN (pulldown or low-side) transistor. The output NPN sinks current

when the negative input voltage is higher than the positive input voltage and the offset voltage. The VOL is

resistive and scales with the output current. See the Specifications section for VOL values with respect to the

output current.

7.4 Device Functional Modes

7.4.1 Voltage Comparison

The comparator operates solely as a voltage comparator, comparing the differential voltage between the positive

and negative pins and outputting a logic low or high impedance (logic high with pullup) based on the input

differential polarity.