LM195,LM395 LM195/LM395 Ultra Reliable Power Transistors Literature Number: SNOSBO4BLM195/LM395 Ultra Reliable Power Transistors July 2000 LM195/LM395 Ultra Reliable Power Transistors ance, it is necessary to insert a 5.0k resistor in series with General Description the base lead to prevent possible emitter follower oscilla- The LM195/LM395 are fast, monolithic power integrated tions. Although the device is usually stable as an emitter circuits with complete overload protection. These devices, follower, the resistor eliminates the possibility of trouble with- which act as high gain power transistors, have included on out degrading performance. Finally, since it has good high the chip, current limiting, power limiting, and thermal over- frequency response, supply bypassing is recommended. load protection making them virtually impossible to destroy For low-power applications (under 100 mA), refer to the from any type of overload. In the standard TO-3 transistor LP395 Ultra Reliable Power Transistor. power package, the LM195 will deliver load currents in ex- The LM195/LM395 are available in the standard TO-3, Kovar cess of 1.0A and can switch 40V in 500 ns. TO-5, and TO-220 packages. The LM195 is rated for opera- The inclusion of thermal limiting, a feature not easily avail- tion from 55C to +150C and the LM395 from 0C to able in discrete designs, provides virtually absolute protec- +125C. tion against overload. Excessive power dissipation or inad- equate heat sinking causes the thermal limiting circuitry to Features turn off the device preventing excessive heating. n Internal thermal limiting The LM195 offers a significant increase in reliability as well n Greater than 1.0A output current as simplifying power circuitry. In some applications, where protection is unusually difficult, such as switching regulators, n 3.0 A typical base current lamp or solenoid drivers where normal power dissipation is n 500 ns switching time low, the LM195 is especially advantageous. n 2.0V saturation The LM195 is easy to use and only a few precautions need n Base can be driven up to 40V without damage be observed. Excessive collector to emitter voltage can de- n Directly interfaces with CMOS or TTL stroy the LM195 as with any power transistor. When the n 100% electrical burn-in device is used as an emitter follower with low source imped- Simplified Circuit 1.0 Amp Lamp Flasher 00600916 00600901 2004 National Semiconductor Corporation DS006009 www.national.com