
TL/H/9059
L
August 1992
LM196/LM396 10 Amp Adjustable Voltage Regulator
General Description
The LM196 is a 10 amp regulator, adjustable from 1.25V to
15V, which uses a revolutionary new IC fabrication structure
to combine high power discrete transistor technology with
modern monolithic linear IC processing. This combination
yields a high-performance single-chip regulator capable of
supplying in excess of 10 amps and operating at power lev-
els up to 70 watts. The regulators feature on-chip trimming
of reference voltage to
g
0.8% and simultaneous trimming
of reference temperature drift to 30 ppm/
§
C typical. Thermal
interaction between control circuitry and the pass transistor
which affects the output voltage has been reduced to ex-
tremely low levels by strict attention to isothermal layout.
This interaction, called thermal regulation, is 100% tested.
These new regulators have all the protection features of
popular lower power adjustable regulators such as LM117
and LM138, including current limiting and thermal limiting.
The combination of these features makes the LM196 im-
mune to blowout from output overloads or shorts, even if
the adjustment pin is accidentally disconnected. All devices
are ‘‘burned-in’’ in thermal shutdown to guarantee proper
operation of these protective features under actual overload
conditions.
Output voltage is continuously adjustable from 1.25V to
15V. Higher output voltages are possible if the maximum
input-output voltage differential specification is not exceed-
ed. Full load current of 10A is available at all output volt-
ages, subject only to the maximum power limit of 70W and
of course, maximum junction temperature.
The LM196 is exceptionally easy to use. Only two external
resistors are used to to set output voltage. On-chip adjust-
ment of the reference voltage allows a much tighter specifi-
cation of output voltage, eliminating any need for trimming in
most cases. The regulator will tolerate an extremely wide
range of reactive loads, and does not depend on external
capacitors for frequency stabilization. Heat sink require-
ments are much less stringent, because overload situations
do not have to be accounted forDonly worst-case full load
conditions.
The LM196 is in a TO-3 package with oversized (0.060
×
)
leads to provide best possible load regulation. Operating
junction temperature range is
b
55
§
C to
a
150
§
C. The
LM396 is specified for a 0
§
C to
a
125
§
C junction tempera-
ture range.
Features
Y
Output pre-trimmed to
g
0.8%
Y
10A guaranteed output current
Y
P
a
Product Enhancement tested
Y
70W maximum power dissipation
Y
Adjustable outputD1.25V to 15V
Y
Internal current and power limiting
Y
Guaranteed thermal resistance
Y
Output voltage guaranteed under worst-case conditions
R1
**
R2 should be same type as R1, with TC track-
ing of 30 ppm/
§
C or better.
Y
Output is short circuit protected
Typical Applications
V
OUT
e
(1.25V)
R1
a
R2
a
I
ADJ
(R2)
TL/H/9059–1
*
For best TC of V
OUT
, R1 should be wirewound
or metal film, 1% or better.
2
C1 is necessary only if main filter capacitor is
more than 6
×
away, assuming
Y
18 or larger
leads.
22
C2 is not absolutely necessary, but is suggest-
ed to lower high frequency output impedance.
Output capacitors in the range of 1
m
F to
1000
m
F of aluminum or tantalum electrolytic
are commonly used to provide improved out-
put impedance and rejection of transients.
ê
C3 improves ripple rejection, output imped-
ance, and noise. C2 should be 1
m
F or larger
close to the regulator if C3 is used.
FIGURE 1. Basic 1.25V to 15V Regulator
C
1995 National Semiconductor Corporation
RRD-B30M115/Printed in U. S. A.