lm613i-mdc National Semiconductor Corporation, lm613i-mdc Datasheet - Page 21

• Manufacturer Part Number: lm613i-mdc
• Description: Dual Operational Amplifiers, Dual Comparators, And Adjustable Reference
• Manufacturer: National Semiconductor Corporation

Application Information
Comparator Output Stage
The comparators, like the LM139 series, have open-collector
output stages. A pull-up resistor must be added from each
output pin to a positive voltage for the output transistor to
switch properly. When the output transistor is OFF, the out-
put voltage will be this external positive voltage.
For the output voltage to be under the TTL-low voltage
threshold when the output transistor is ON, the output cur-
rent must be less than 8 mA (over temperature). This im-
pacts the minimum value of pull-up resistor.
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The offset voltage may increase when the output voltage is
low and the output current is less than 30 µA. Thus, for best
accuracy, the pull-up resistor value should be low enough to
allow the output transistor to sink more than 30 µA.
Op Amp and Comparator Input Stage
The lateral PNP input transistors, unlike those of most op
amps, have BV
voltage. Also, they have no diode clamps to the positive
supply nor across the inputs. These features make the in-
puts look like high impedances to input sources producing
large differential and common-mode voltages.
EBO
equal to the absolute maximum supply
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