Transistor

B737 Datasheet – 40V, 300mA, PNP Transistor – Rohm

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Part Number: B737, 2SB737

Funtion: -40V, -300mA, Low rbb Low Noise Amp

Package: TO-92 Type

Manufacturer: Rohm

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B737 datasheet

Description

B737 is a low-noise PNP bipolar junction transistor from Rohm, housed in a TO-92 package and rated for up to -40V and -300mA operation. It features ultra-low noise characteristics, low base resistance, and excellent noise response, making it suitable for sensitive analog signal applications. This transistor is commonly used in low-noise amplifiers, audio circuits, and precision signal processing stages.

Features

  • PNP bipolar transistor with -40V voltage rating
  • Low noise performance optimized for audio and signal applications
  • Ultra-low base resistance (rbb’ ≈ 2Ω)
  • Excellent noise response at low source resistance (Rg)
  • Low voltage noise characteristics
  • Complementary pair with 2SD786 (NPN)
  • TO-92 through-hole package

Absolute Maximum Ratings (Tc = 25 °C)

Parameter Symbol Value Unit
Collector-Base Voltage VCBO -50 V
Collector-Emitter Voltage VCEO -40 V
Emitter-Base Voltage VEBO -5 V
Collector Current IC -300 mA
Collector Power Dissipation PC 0.25 W
Junction Temperature Tj 125 °C

Design Notes

  • Ideal for low-noise amplifier stages where base resistance and noise figure are critical
  • Maintain low source impedance to fully benefit from low-noise characteristics
  • Ensure proper biasing to operate in the linear region for analog applications
  • Thermal limits should be considered due to relatively low power dissipation rating
  • Pair with 2SD786 for complementary push-pull amplifier designs

Typical Circuit Usage

  • Low-noise audio preamplifiers
  • Small-signal amplification stages
  • Differential amplifier input stages
  • Sensor signal conditioning circuits

How to Choose This Part

  • Select for applications requiring low noise and stable gain characteristics
  • Suitable for low-current analog signal amplification
  • Choose when complementary pairing with NPN transistor is needed
  • Verify voltage and current ratings match application requirements

Applications

  • Audio amplification systems
  • Precision analog circuits
  • Measurement and instrumentation equipment
  • Low-noise signal processing systems

Alternative / Equivalent Products

  • 2SA1015
  • BC560
  • 2SA970
  • 2SD786 (complementary NPN)

B737 Datasheet

2SD822 Transistor – 600V, 7A, NPN Transistor

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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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2SD822 datasheet pdf

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

2SD822 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

2SD822 pdf