SMBJ33CA

Suin · ‎2026-01-20

Hi, I have SMBJ33CA-TR diodes. I am measuring the breakdown voltage, Ubr. According to the technical documentation on your website, the acceptable values range from 36.7 V to 38.6 V. However, I am measuring values above these limits, with Ubr = 40.163 V, Ubr = 39.260 V. Please clarify if the documentation has changed, and if so, whether the Ubr limits are higher than those specified in the DS1283 - Rev 13 - October 2024 datasheet.

Peter BENSCH · ‎2026-01-21

Welcome @Suin, to the community!

The values specified in the data sheet apply to the environmental conditions specified therein. In addition, the SMBJ33CA-TR is not a zener diode with static data, but a TVS designed to protect against voltage pulses (see e.g. data sheet, fig. 1 and 2). The breakdown voltage is also determined by the dynamic resistance, which increases with increasing pulse duration (see data sheet, fig. 6).

This is therefore not a data sheet error, but has to do with your measurement method.

Regards
/Peter

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FGUIT · ‎2026-01-21

Hi,

SMBJ33CA datasheet specifies minimum and typical V_BR values. Maximum value is not specified. V_{BR Min}= 36.7 V, V_{BR Typ} = 38.6 V.

Equivalent part is available on SM6T family, SM6T39CA. Maximum V_BR value is specified.
V_{BR Max} = 41 V. Value you measured is lower than this maximum value.

Hoping it answers your question.

Best regards.

Fabrice.