LP395 Ultra Reliable Power Transistor General Description The LP395 is a fast monolithic transistor with complete overload protection. This very high gain transistor has included on the chip, current limiting, power limiting, and thermal overload protection, making it difficult to destroy from almost any type of overload. Available in an epoxy TO-92 transistor package this device is guaranteed to deliver 100 mA. Thermal limiting at the chip level, a feature not available in discrete designs, provides comprehensive protection against overload. Excessive power dissipation or inadequate heat sinking causes the thermal limiting circuitry to turn off the device preventing excessive die temperature. The LP395 offers a significant increase in reliability while simplifying protection circuitry. It is especially attractive as a small incandescent lamp or solenoid driver because of its low drive requirements and blowout-proof design. The LP395 is easy to use and only a few precautions need be observed. Excessive collector to emitter voltage can destroy the LP395 as with any transistor. When the device is used as an emitter follower with a low source impedance, it is necessary to insert a 4.7 kΩ resistor in series with the base lead to prevent possible emitter follower oscillations. Also since it has good high frequency response, supply by-passing is recommended. Areas where the LP395 differs from a standard NPN transistor are in saturation voltage, leakage (quiescent) current and Connection Diagram in base current. Since the internal protection circuitry requires voltage and current to function, the minimum voltage across the device in the on condition (saturated) is typically 1.6 Volts, while in the off condition the quiescent (leakage) current is typically 200 µA. Base current in this device flows out of the base lead, rather than into the base as is the case with conventional NPN transistors. Also the base can be driven positive up to 36 Volts without damage, but will draw current if driven negative more than 0.6 Volts. Additionally, if the base lead is left open, the LP395 will turn on. The LP395 is a low-power version of the 1-Amp LM195/ LM295/LM395 Ultra Reliable Power Transistor. The LP395 is rated for operation over a −40˚C to +125˚C range. Features n n n n n n n Internal thermal limiting Internal current and power limiting Guaranteed 100 mA output current 0.5 µA typical base current Directly interfaces with TTL or CMOS +36 Volts on base causes no damage 2 µs switching time Typical Applications Fully Protected Lamp Driver TO-92 Package DS005525-1 Order Number LP395Z See NS Package Z03A DS005525-3 © 1999 National Semiconductor Corporation DS005525 www.national.com LP395 Ultra Reliable Power Transistor April 1998 Absolute Maximum Ratings (Note 1) Collector to Emitter Voltage Collector to Base Voltage Base to Emitter Voltage (Forward) Base to Emitter Voltage (Reverse) Base to Emitter Current (Reverse) Collector Current Limit Power Dissipation Operating Temperature Range Storage Temperature Range Lead Temp. (Soldering, 10 seconds) 36V 36V 36V 10V 20 mA Internally Limited Internally Limited −40˚C to +125˚C −65˚C to +150˚C 260˚C Electrical Characteristics Symbol Parameter Conditions Typical Tested Design Units Limit Limit (Limit) (Note 3) VCE Collector to Emitter 0.5 mA ≤ IC ≤ 100 mA 36 Operating Voltage ICL Collector Current Limit (Note 5) (Note 4) 36 V(Max) (Note 2) VBE = 2V, VCE = 36V VBE = 2V, VCE = 15V VBE = 2V, 2V ≤ VCE ≤ 6V IB Base Current IQ Quiescent Current VCE(SAT) Saturation Voltage 0 ≤ IC ≤ 100 mA VBE = 0V, 0 ≤ VCE ≤ 36V VBE = 2V, IC = 100 mA BVBE Base to Emitter Break- 0 ≤ VCE ≤ 36V, IB = 2 µA 45 25 20 90 60 50 mA(Min) mA(Min) 130 100 100 mA(Min) −0.3 −2.0 −2.5 µA(Max) 0.24 0.50 0.60 mA(Max) 1.82 2.00 2.10 V(Max) 36 36 V(Min) 0.79 0.90 V(Max) 1.40 V (Max) down Voltage (Note 5) VBE Base to Emitter Voltage (Note 6) tS Switching Time IC = 5 mA IC = 100 mA (Note 5) VCE = 20V, RL = 200Ω 0.69 1.02 2 µs VBE = 0V, +2V, 0V θJA Thermal Resistance 0.4" leads soldered to Junction to Ambient printed circuit board 150 180 ˚C/W (Max) 0.125" leads soldered to 130 160 printed circuit board ˚C/W (Max) Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is functional, but do not guarantee specific performance limits. Note 2: Parameters identified with boldface type apply at temp. extremes. All other numbers, unless noted apply at +25˚C. Note 3: Guaranteed and 100% production tested. Note 4: Guaranteed (but not 100% production tested) over the operating temperature and supply voltage ranges. These limits are not used to calculate outgoing quality levels. Note 5: These numbers apply for pulse testing with a low duty cycle. Note 6: Base positive with respect to emitter. Simplified Circuit Applications Information One failure mode incandescent lamps may experience is one in which the filament resistance drops to a very low value before it actually blows out. This is especially rough on most solid-state lamp drivers and in most cases a lamp failure of this type will also cause the lamp driver to fail. Because of its high gain and blowout-proof design, the LP395 is an ideal candidate for reliably driving small incandescent lamps. Additionally, the current limiting characteristics of the LP395 are advantageous as it serves to limit the cold filament inrush current, thus increasing lamp life. DS005525-5 www.national.com 2 Typical Performance Characteristics 5 Volt Transfer Function 36 Volt Transfer Function DS005525-10 Available Collector Current Collector Characteristics DS005525-12 DS005525-11 Quiescent Collector Current DS005525-13 DS005525-14 Saturation Voltage DS005525-15 Collector Current Threshold DS005525-9 3 www.national.com Typical Applications Lamp Flasher (Short Circuit Proof) Optically Isolated Switch DS005525-7 DS005525-6 Two Terminal Current Limiter Composite PNP DS005525-2 DS005525-8 www.national.com 4 LP395 Ultra Reliable Power Transistor Physical Dimensions inches (millimeters) unless otherwise noted Order Number LP395Z NS Package Z03A LIFE SUPPORT POLICY NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL COUNSEL OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein: 1. 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