LM193J/883 National Semiconductor, LM193J/883 Datasheet - Page 3

• Manufacturer Part Number: LM193J/883
• Description: IC,VOLT COMPARATOR,DUAL,BIPOLAR,DIP,8PIN,CERAMIC
• Manufacturer: National Semiconductor

Performance
A detail of one of the base sections is shown in Figure 4. An
interdigitated structure is used with alternating base contacts
Collector to Emitter Voltage
Base to Emitter Voltage (max.)
Peak Collector Current (internally limited)
Reverse Base Emitter Voltage
Base to Emitter Voltage (I
Base Current
Saturation Voltage
Switching Time (turn on or turn off)
Power Dissipation (internally limited)
Thermal Limit Temperature
Maximum Operating Temperature
Thermal Resistance (Junction to Case)
TABLE 1. Typical Performance
FIGURE 3. LM195 Chip
(Continued)
c
= 1.0 amp)
00741803
1.8 amps
35 watts
2.3˚C/W
500 ns
165˚C
150˚C
3 µA
0.9V
42V
42V
20V
2V
3
and emitter stripes. Integrated into each emitter is an indi-
vidual emitter ballasting resistor to insure equal current shar-
ing between emitters in each section. Aluminum metalization
runs the length of the emitter stripe to prevent lateral voltage
drop from debiasing a section of the stripe at high operating
currents. All current in the stripe flows out through the small
ballasting resistor where it is summed with the currents from
the other stripes in the section. The partitioning in conjunc-
tion with the emitter resistor gives a power transistor with
large safe-area and good power handling capability.
Applications
With the full protection and high gain offered by this mono-
lithic power transistor, circuit design is considerably simpli-
fied. The inclusion of thermal limiting, not normally available
in discrete design allows the use of smaller heat sinks than
with conventional protection circuitry. Further, circuits where
protection
impossible — now cause no problems.
For example, with only current limiting, the power transistor
heat sink must be designed to dissipate worst case overload
power dissipation at maximum ambient temperature. When
the power transistor is thermally limited, only normal power
need be dissipated by the heat sink. During overload, the
device is allowed to heat up and thermally limit, drastically
reducing the size of the heat sink needed.
Switching circuits such as lamp drivers, solenoid drivers or
switching regulators do not dissipate much power during
normal operation and usually no heat sink is necessary.
However, during overload, the full supply voltage times the
maximum output current must be dissipated. Without a large
heat sink standard power transistors are quickly destroyed.
Using this new device is easier than standard power transis-
tors but a few precautions should be observed. About the
only way the device can be destroyed is excessive collector
to emitter voltage or improper power supply polarity. Some-
times when used as an emitter follower, low level high fre-
quency oscillations can occur. These are easily cured insert-
ing a 5k-10k resistor in series with the base lead. The
resistor will eliminate the oscillation without effecting speed
or performance. Good power supply bypassing should also
be used since this is a high frequency device.
of
the
power
device
is
difficult — if
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