What is 2SD822?
This is high-voltage NPN silicon power transistor.
Function: 600V, 7A, Silicon NPN Transistor
Package: TO-126 Type
Manufacturer: Toshiba
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Description
The 2SD822 is a high-voltage NPN silicon power transistor specifically designed for horizontal output applications in CRT color televisions. It is optimized for high-voltage switching, fast transition times, and robust operation under inductive load conditions. With a collector-base voltage rating up to 1500V and strong switching performance, it is well-suited for flyback transformer drive circuits and similar high-energy pulse applications.
Features
- High collector-base voltage capability (VCBO = 1500V)
- High-speed switching (tf ≈ 1.0µs max)
- Low collector-emitter saturation voltage
- Glass-passivated collector-base junction for improved reliability
- Designed for high-voltage pulse and inductive load operation
- Good ruggedness under flyback conditions
Pinout
Typical Application Context
- CRT horizontal deflection output stage
- Flyback transformer driver circuits
- High-voltage pulse generators
- Switching power stages with inductive loads
Absolute Maximum Ratings (Ta = 25 °C)
| Parameter | Symbol | Value | Unit |
| Collector-Base Voltage | VCBO | 1500 | V |
| Collector-Emitter Voltage | VCEO | 600 | V |
| Emitter-Base Voltage | VEBO | 5 | V |
| Collector Current | IC | 7 | A |
| Emitter Current | IE | -7 | A |
| Power Dissipation (Tc = 25°C) | PC | 50 | W |
| Junction Temperature | Tj | 150 | °C |
| Storage Temperature | Tstg | -55 to 150 | °C |
Design Notes
- Optimized for flyback operation — capable of handling high voltage spikes generated by transformer collapse
- Fast fall time (tf) is critical for minimizing switching loss in horizontal deflection circuits
- Requires proper snubber or damper network to control voltage overshoot
- Base drive must be sufficiently strong (e.g., IB ≈ IC/5) to ensure deep saturation during switching
- Thermal design is essential due to high pulse energy and switching stress
Typical Circuit Usage
- CRT horizontal output transistor (HOT stage)
- Flyback transformer switching
- High-voltage pulse switching circuits
- Inductive load switching with high dv/dt stress
How to Choose This Part
- Select for high-voltage (>600V) switching environments
- Ideal for legacy CRT or flyback-based designs
- Ensure proper base drive and protection network design
- Evaluate switching speed vs modern MOSFET/IGBT alternatives
- Confirm thermal and SOA margins under pulsed conditions
Applications
- Color TV horizontal output stages
- High-voltage switching circuits
- Flyback power supplies
- Pulse power systems
- Industrial high-voltage drivers
Alternative / Equivalent Products
- BU508A (common HOT transistor alternative)
- 2SD1555 (similar high-voltage transistor)
- 2SC5388 (modern replacement option)
- BU2520AF (integrated damper diode type)
- IGBT or MOSFET replacements (depending on topology redesign)
2SD822 Datasheet PDF Download
