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SSDI Develops New SDR20MF Diodes to Nullify Over-Voltage Condition
November 08, 2016


(Repetitive High Reverse Energy Rated,
> 500 µJ at Ipk max = 200 mA)

SSDI Responds Quickly to Resolve Customer's Issue
When a customer was experiencing failures in a high voltage military power supply, SSDI engineers worked alongside the customer's team for several months over multiple conference calls, site visits, and a battery of tests to determine that stray high voltage transients in the system were causing an over-voltage condition. These high voltage transients were difficult to detect and model, and were not realized by the customer until SSDI became involved. Since re-designing the power supply was not an option, SSDI offered to develop a more rugged diode to withstand the high voltage transients. With nearly 50 years of experience manufacturing high voltage assemblies, SSDI engineers quickly responded by developing the SDR20MF series of diodes and incorporated the new diodes in the re-design of the high voltage assembly. SSDI's technical expertise, long heritage in high voltage assembly design, and its unique flexibility in manufacturing high performance and high reliability solutions were critical in identifying and resolving the customer's issue.

Advantages of the SDR20MF Diodes The original design of the high voltage assembly using 9 amp internal hermetic diodes continues to be used in various military applications and has proven its high reliability over the past 30+ years. The SDR20MF's capability of absorbing > 500 µJ at Ipk max = 200 mA offers four times the level required by the original specification. The increase of output current from switching to the 20 amp SDR20MF internal diodes simplified the design by reducing the number of internal diodes by 66%. Furthermore, the SDR20MF does not require any shunting resistors, which also simplifies operation of the rectifiers within high voltage assemblies and lends itself to more compact designs. In the adjacent comparison with the commonly used 1N5420, the improvements in electrical performance with the SDR20MF are quite staggering considering the similar physical dimensions. The SDR20MF also provides higher reliability because it is produced at SSDI's wafer fabrication facility on its S-level QPL line.

SSDI is the Best Source for High Voltage Assemblies
SSDI began supplying high voltage assemblies for military applications in 1967. The number of suppliers providing these devices continues to dwindle and alternative sources have been plagued with poor quality and delivery issues. In contrast, SSDI continues to set the standard for high reliability assemblies. As featured earlier, SSDI continually pushes the existing standards of high performance and high density to meet our customer's needs. SSDI's engineers have over 700 years of experience in the semiconductor manufacturing field at companies such as Microsemi, International Rectifier, Intel, TRW, Motorola, Semtech, and IBM. As bridge and high voltage assemblies tend to fit a specific form and function within an application, this technical expertise becomes indispensible in developing the best solution for new designs or sustainment projects. Contact SSDI today to see how its resources can benefit your high voltage applications.




  • Fast reverse recovery: 250 nsec typical
  • PIV to 1000 volts
  • Repetitive high reverse energy rated
    (> 500 µJ at IPK max = 200 mA)
  • Hermetically sealed
  • Low reverse leakage current
  • Replaces larger DO-4 rectifiers
  • Low thermal resistance
  • Available in axial and square tab versions TX, TXV, and S-level screening available (Screening based on MIL-PRF-19500. Screening flows available on request.)

Benefits / Applications

  • Unmatched standards of reliability for PRV's up to 1000 V, as well as at lower voltages
  • Protection of other circuit components against overvoltage through rigidly specified max / min avalanche characteristics
  • Simplified series operation of rectifiers in high voltage applications - no shunting resistors necessary for Controlled Avalanche Rectifiers; makes possible compact high voltage assemblies
  • Can operate in the avalanche breakdown region at high voltages

Click here to view the data sheet

Contact SSDI today to request
more information or samples:

(562) 404-4474

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