LM613AIN National Semiconductor, LM613AIN Datasheet - Page 16

• Manufacturer Part Number: LM613AIN
• Description: Dual Operational Amplifiers/ Dual Comparators/ and Adjustable Reference
• Manufacturer: National Semiconductor

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Application Information
R1 = Vr/I = 1.24/32µ = 39k
R2 = R1 {(Vro/Vr) − 1} = 39k {(5/1.24) − 1)} = 118k
Understanding that V
sistors, and capacitors may be tied to the FEEDBACK pin, a
range of V
FIGURE 6. Output Voltage has Negative Temperature
FIGURE 5. Resistors R1 and R2 Program Reference
FIGURE 7. Output Voltage has Positive TC
Coefficient (TC) if R2 has Negative TC
r
temperature coefficients may be synthesized.
Output Voltage to be 5V
if R1 has Negative TC
r
is fixed and that voltage sources, re-
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(Continued)
16
Connecting a resistor across Cathode-to-FEEDBACK cre-
ates a 0 TC current source, but a range of TCs may be
synthesized.
I = Vr/R1 = 1.24/R1
FIGURE 8. Diode in Series with R1 Causes Voltage
FIGURE 10. Proportional-to-Absolute-Temperature
Across R1 and R2 to be Proportional to Absolute
FIGURE 9. Current Source is Programmed by R1
FIGURE 11. Negative-TC Current Source
Temperature (PTAT)
Current Source
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