Symbol

Parameter

Conditions

LM338

Units

Min

Typ

Max

∆V

R/T

Temperature Stability

T

1

%

I

Minimum Load Current

V

3.5

10

mA

I

CL

Current Limit

V

DC

58

A

0.5 ms Peak

712

A

V

1

A

V

N

RMS Output Noise, % of V

OUT

10 Hz

≤ f ≤ 10 kHz

0.003

%

Ripple Rejection Ratio

V

60

dB

V

60

75

dB

Long-Term Stability

T

0.3

1

%

θ

JC

Thermal Resistance

K Package

1

˚C/W

Junction to Case

T Package

4

˚C/W

θ

JA

Thermal Resistance, Junction to

K Package

35

˚C/W

Ambient (No Heat Sink)

T Package

50

˚C/W

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

tended to be functional, but do not guarantee specific performance limits. For guaranteed specifications and test conditions, see the Electrical Characteristics.

Note 2: These specifications are applicable for power dissipations up to 50W for the TO-3 (K) package and 25W for the TO-220 (T) package. Power dissipation is

guaranteed at these values up to 15V input-output differential. Above 15V differential, power dissipation will be limited by internal protection circuitry. All limits (i.e.,

the numbers in the Min. and Max. columns) are guaranteed to National’s AOQL (Average Outgoing Quality Level).

Note 3: Regulation is measured at a constant junction temperature, using pulse testing with a low duty cycle. Changes in output voltage due to heating effects are

covered under the specifications for thermal regulation.

Note 4: Refer to RETS138K drawing for military specifications of LM138K.

Typical Performance Characteristics

Current Limit

DS009060-32

Current Limit

DS009060-33

Current Limit

DS009060-34

Load Regulation

DS009060-35

Dropout Voltage

DS009060-36

Adjustment

Current

DS009060-37

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