Electrical Characteristics (Continued)
Symbol
Parameter
Conditions
LM338
Typ
1
Units
Min
Max
10
∆VR/T
LOAD(Min)
ICL
Temperature Stability
Minimum Load Current
Current Limit
TMIN ≤ TJ ≤ TMAX
%
=
I
VIN − VOUT 35V
3.5
mA
VIN − VOUT ≤ 10V
DC
5
7
8
A
A
0.5 ms Peak
12
=
VIN − VOUT 30V
1
A
VN
RMS Output Noise, % of VOUT
Ripple Rejection Ratio
10 Hz ≤ f ≤ 10 kHz
0.003
60
%
dB
=
=
=
VOUT 10V, f 120 Hz, CADJ 0 µF
=
=
=
VOUT 10V, f 120 Hz, CADJ 10 µF
60
75
dB
=
Long-Term Stability
TJ 125˚C, 1000 hrs
0.3
1
1
4
%
θJC
Thermal Resistance
K Package
T Package
K Package
T Package
˚C/W
˚C/W
˚C/W
˚C/W
Junction to Case
θJA
Thermal Resistance, Junction to
Ambient (No Heat Sink)
35
50
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
Current Limit
Current Limit
DS009060-32
DS009060-33
DS009060-34
Load Regulation
Dropout Voltage
Adjustment
Current
DS009060-35
DS009060-36
DS009060-37
3
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