NTE309K
Integrted Circuit
Voltage Regulator
Description:
The NTE309K is a complete 5V regulator fabricated on a single silicon chip. It is designed for local
regulation on digital logic cards, eliminating the distribution problems associated with singlepoint
regulation. With the TO3 power package, the available output current is greater than 1A.
The regulator is essentially blowout proof. Current limiting is included to limit the peak output current
to a safe value. In addition, the thermal shutdown is provided to keep the IC from overheating. If inter-
nal dissipation becomes too great, the regulator will shut down to prevent excessive heating.
Considerable effort was expended to make these devices easy to use and to minimize the number
of external components. It is not necessary to bypass the output, although this does improve transient
response somewhat. Input bypassing is needed, however, if the regulator is located very far from the
filter capacitor of the power supply. Stability is also achieved by methods that provide very good rejec-
tion of load or line transients as are usually seen with TTL logic.
Although designed primarily as a fixedvoltage regulator, the output can be set to voltages above 5V,
as shown below. It is also possible to use the circuits as the control element in precision regulators,
taking advantage of the good currenthandling capability and the thermal overload protection.
Features:
D
Specified to be compatible, worst case, with TTL and DTL
D
Output current in excess of 1A
D
Internal thermal overload protection
D
No external components required
Absolute Maximum Ratings:
Input Voltage, V
IN
35V
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Power Dissipation, P
D
Internally Limited
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Operating Junction Temperature Range, T
opr
0
C to +125
C
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Storage Temperature Range, T
stg
65
C to +150
C
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Typical Thermal Resistance, JunctiontoCase (Note 1), R
thJC
2.5
C/W
. . . . . . . . . . . . . . . . . . . . . . .
Lead Temperature (Soldering, 10 seconds), T
L
+300
C
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Note 1. Without a heat sink, the thermal resistance of the TO3 package is approximately 35
C/W.
With a heat sink,
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