Power Transistors. LM195 Datasheet

LM195 Datasheet PDF

Part Number



Ultra Reliable Power Transistors


National Semiconductor

Total Page 13 Pages
Download LM195 Datasheet

June 1999
Ultra Reliable Power Transistors
General Description
The LM195/LM395 are fast, monolithic power transistors
with complete overload protection. These devices, which act
as high gain power transistors, have included on the chip,
current limiting, power limiting, and thermal overload protec-
tion making them virtually impossible to destroy from any
type of overload. In the standard TO-3 transistor power pack-
age, the LM195 will deliver load currents in excess of 1.0A
and can switch 40V in 500 ns.
The inclusion of thermal limiting, a feature not easily avail-
able in discrete designs, provides virtually absolute protec-
tion against overload. Excessive power dissipation or inad-
equate heat sinking causes the thermal limiting circuitry to
turn off the device preventing excessive heating.
The LM195 offers a significant increase in reliability as well
as simplifying power circuitry. In some applications, where
protection is unusually difficult, such as switching regulators,
lamp or solenoid drivers where normal power dissipation is
low, the LM195 is especially advantageous.
The LM195 is easy to use and only a few precautions need
be observed. Excessive collector to emitter voltage can de-
stroy the LM195 as with any power transistor. When the de-
vice is used as an emitter follower with low source imped-
ance, it is necessary to insert a 5.0k resistor in series with
the base lead to prevent possible emitter follower oscilla-
tions. Although the device is usually stable as an emitter fol-
lower, the resistor eliminates the possibility of trouble without
degrading performance. Finally, since it has good high fre-
quency response, supply bypassing is recommended.
For low-power applications (under 100 mA), refer to the
LP395 Ultra Reliable Power Transistor.
The LM195/LM395 are available in standard TO-3 power
packages and solid Kovar TO-5. The LM195 is rated for op-
eration from −55˚C to +150˚C and the LM395 from 0˚C to
n Internal thermal limiting
n Greater than 1.0A output current
n 3.0 µA typical base current
n 500 ns switching time
n 2.0V saturation
n Base can be driven up to 40V without damage
n Directly interfaces with CMOS or TTL
n 100% electrical burn-in
Simplified Circuit
© 1999 National Semiconductor Corporation DS006009

Connection Diagrams
TO-3 Metal Can Package
TO-220 Plastic Package
Bottom View
Order Number LM195K/883
See NS Package Number K02A
Case is Emitter
Top View
Order Number LM395T
See NS Package Number T03B
TO-5 Metal Can Package
Bottom View
Order Number LM195H/883
See NS Package Number H03B

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