BLW98 - N-P-N Silicon Planar Epitaxial Transistor

Overview

The BLW98 is a high-performance N-P-N silicon planar epitaxial transistor designed for demanding applications requiring excellent thermal stability and reliable operation. This component features diffused emitter ballasting resistors which significantly improve current sharing and thermal stability under high-power conditions. The transistor is fabricated using advanced planar epitaxial technology, ensuring consistent performance and high reliability in various operating conditions.

With its robust construction and optimized design, the BLW98 is particularly suited for RF power amplification and other applications where thermal management and consistent performance are critical requirements. The device offers a combination of high power gain, good linearity, and thermal stability that makes it ideal for professional and industrial applications.

Key Features

• N-P-N silicon planar epitaxial construction for consistent performance
• Integrated diffused emitter ballasting resistors for improved thermal stability
• Excellent current sharing characteristics in parallel configurations
• High power gain across a wide frequency range
• Optimized for RF power amplification applications
• Robust construction for reliable operation in demanding environments
• Low thermal resistance package design
• Good linearity characteristics for high-fidelity amplification

Applications

The BLW98 transistor is designed for a variety of professional and industrial applications where high power and thermal stability are required:

RF Power Amplification

• HF and VHF transmitters
• RF power amplifiers for communication systems
• Industrial RF generators
• Amateur radio equipment

General Purpose Applications

• High-power switching circuits
• Linear power amplifiers
• Industrial control systems
• Power supply regulation

Specialized Uses

• RF heating systems
• Plasma generation equipment
• Medical diathermy equipment
• Scientific instrumentation

Electrical Characteristics

The following tables detail the key electrical specifications of the BLW98 transistor under standard test conditions (unless otherwise noted):

Absolute Maximum Ratings

• Collector-Emitter Voltage (V_CEO): 36V
• Collector-Base Voltage (V_CBO): 60V
• Emitter-Base Voltage (V_EBO): 5V
• Collector Current (I_C): 4A continuous
• Total Power Dissipation (P_tot): 40W at 25°C case temperature
• Junction Temperature (T_j): 200°C maximum
• Storage Temperature Range: -65°C to +200°C

Thermal Characteristics

• Thermal Resistance, Junction to Case (R_thJC): 3.125°C/W
• Thermal Resistance, Junction to Ambient (R_thJA): 62.5°C/W (with infinite heatsink)

Small Signal Characteristics

• Current Gain Bandwidth Product (f_T): 60MHz typical
• Output Capacitance (C_ob): 30pF typical at V_CB = 10V
• Input Impedance (Z_in): 5Ω typical at 30MHz

Large Signal Characteristics

• Power Gain (G_p): 13dB typical at 30MHz
• Collector Efficiency (η): 60% typical in class C operation
• Saturation Voltage (V_CE(sat)): 0.5V maximum at I_C = 2A

Package Information

The BLW98 is available in a robust, industry-standard package designed for optimal thermal performance and mechanical reliability:

Package Type

SOT-122A (TO-39 variant) metal can package with isolated mounting flange

Package Dimensions

• Overall Height: 9.65mm maximum
• Body Diameter: 10.67mm nominal
• Lead Diameter: 0.51mm nominal
• Mounting Hole Diameter: 3.96mm
• Flange Thickness: 1.52mm nominal

Package Materials

• Case Material: Nickel-plated steel
• Terminals: Gold-plated Kovar leads
• Isolation: Mica washer included for flange isolation

Mounting Considerations

For optimal thermal performance, the following mounting practices are recommended:

• Use thermal compound between package and heatsink
• Apply proper torque (0.6 Nm) to mounting hardware
• Ensure flatness of mounting surface (within 0.05mm)
• Maintain clean contact surfaces free of oxidation

Reliability and Qualification

The BLW98 transistor undergoes rigorous testing to ensure reliability in demanding applications:

Environmental Testing

• Temperature Cycling: -65°C to +200°C, 100 cycles
• Humidity Resistance: 85°C/85% RH, 1000 hours
• Vibration Resistance: 20G, 20-2000Hz

Electrical Stress Testing

• High Temperature Reverse Bias: 150°C, 1000 hours
• High Temperature Operating Life: 2000 hours at maximum ratings
• ESD Resistance: Passes 2kV Human Body Model

Handling and Storage

To maintain device reliability and prevent damage, observe the following precautions:

ESD Protection

• Always handle in ESD-protected environment
• Use grounded wrist straps when handling
• Store in conductive foam or antistatic containers

Storage Conditions

• Temperature: -40°C to +40°C
• Humidity: < 60% RH
• Avoid corrosive atmospheres

Soldering Recommendations

• Maximum soldering iron temperature: 300°C
• Maximum soldering time: 5 seconds per lead
• Recommended solder: Sn60/Pb40 or equivalent

Ordering Information

The BLW98 is available in several packaging options:

• BLW98/TR: Tape and reel packaging, 500 units per reel
• BLW98/B: Bulk packaging, 100 units per tube
• BLW98-25: 25-piece sample pack

For high-reliability applications, military-grade versions are available with additional screening and documentation. Contact factory for MIL-PRF-19500 qualified versions.