Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is func-

tional, but do not guarantee specific performance limits. For guaranteed specifications and test conditions, see the Electrical Characteristics. The guaranteed speci-

fications apply only for the test conditions listed. Some performance characteristics may degrade when the device is not operated under the listed test conditions.

Note 3: The human body model is a 100 pF capacitor discharged through a 1.5 k

Ω resistor into each pin. The machine model is a 200 pF capacitor discharged di-

rectly into each pin.

Note 4: See AN-450 “Surface Mounting Methods and Their Effect on Product Reliability” or the section titled “Surface Mount” found in any post 1986 National Semi-

conductor Linear Data Book for other methods of soldering surface mount devices.

Note 5: The junction to ambient thermal resistance (

FOR fig NS1382*.

Note 7: Limits are guaranteed to National’s AOQL (Average Outgoing Quality Level).

Note 8: Accuracy is defined as the error between the measured and calculated output voltage at the specified conditions of voltage, current, and temperature (ex-

pressed in˚C).

Note 9: Non-Linearity is defined as the deviation of the calculated output-voltage-versus-temperature curve from the best-fit straight line, over the temperature range

specified.

Note 10: Regulation is measured at constant junction temperature, using pulse testing with a low duty cycle. Changes in output due to heating effects can be com-

puted by multiplying the internal dissipation by the thermal resistance.

Note 11: Negative currents are flowing into the LM20. Positive currents are flowing out of the LM20. Using this convention the LM20 can at most sink −1 µA and

source +16 µA.

Note 12: Load regulation or output impedance specifications apply over the supply voltage range of +2.4V to +5.5V.

Note 13: Line regulation is calculated by subtracting the output voltage at the highest supply input voltage from the output voltage at the lowest supply input voltage.

Typical Performance Characteristics

PCB Layouts Used for Thermal

Measurements

Temperature Error vs Temperature

DS100908-25

DS100908-29

a) Layout used for no heat sink measurements.

DS100908-30

b) Layout used for measurements with small heat hink.

FIGURE 1. PCB Lyouts used for thermal measurements.

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