This is a kind of PNP Transistor.
Part Number: B778, 2SB778
Function: PNP PLANAR TRANSISTOR ( Vceo = -120V )
Package: TO-3P Type
Manufacturer: Wing Shing Computer Components
See the preview image and the PDF file for more information.
Image
Description
The B778 (commonly referenced as 2SB778) is a PNP planar silicon power transistor designed for audio amplification and power conversion applications. It is typically used as the complementary pair to NPN transistors like 2SD998 or similar devices in push-pull amplifier configurations.
This device is optimized for high current handling and power dissipation, making it suitable for medium-to-high power analog and switching circuits.
1. High Current Capability
2. High Power Dissipation
B778 Pinout
Absolute Maximum Ratings
1. Collector-Base Voltage: Vcbo= – 120 V
2. Collector-Emitter Voltage: Vceo = – 120 V
3. Emitter-Base voltage : Vebo = – 6 V
4. Collector Current (DC) : Ic = – 10 A
5.Collector Dissipation : Pc = 80 W
6. Junction Temperature: Tj = 150°C
Design Notes (Critical Points)
- Heat sink is mandatory for high-power operation
- Use emitter resistors (~0.22Ω) for current balancing
- Ensure proper bias network to avoid crossover distortion
- Protect against overcurrent and thermal overload
- Maintain safe operating area (SOA) in linear mode
Typical Applications
- Audio power amplifier output stages
- Hi-Fi stereo systems
- DC-DC converter circuits (linear or low-frequency switching)
- High-current driver stages
- Power regulation circuits
Alternative / Equivalent Products
- 2SB817
- 2SA1941 (higher performance audio pair)
- TIP2955
- MJL1302A (high-end audio PNP)
B778 Datasheet
