Exploding Rectifier Diodes ranks high among the questions found in forms related to restoring test equipment. Vishay’s diode family, made up of the ES1A, ES1B, ES1C and ES1D, provide a nice workaround for the problem.

To understand, let us recapitulate. When a diode is switched “off”, the current initially flows the other way while separating the pn junction. Once this separation has taken place, the diode is “locked” – sadly, quite a bit of power can be dissipated during the switch-off process. Engineers seeking a recapitulation are advised to look at MicroSemi’s application note found by clicking here – it also sourced the figure included here.

A faster reverse recovery time means less current “burn”

The theoretic recovery time in the range of 15ns would lead to an allowed maximum frequency of 66.7 MHz – while this, of course, is much too high, parts working with a 400KhZ or a 1MhZ switching frequency do not need to worry when a Vishay ES1B-E3/61T is in place. The forward current of up to 1A should also be enough for most smaller systems – as things get bigger, different diode families need to be used.

From a technical point of view, the four diode families mainly differ in the amount of reverse voltage they can stand. Our table compares the four candidates – if ES1A vs ES1D is your question, look no further.

Maximum Ratings (Tᴬ = 25 °C unless otherwise noted)

Parameter Symbol ES1A ES1B ES1C ES1D Unit
Device marking code   EA EB EC ED  
Maximum repetitive peak reverse voltage VRRM 50 100 150 200 V
Maximum RMS voltage VRMS 35 70 105 140 V
Maximum DC blocking voltage VDC 50 100 150 200 V
Maximum average forward rectified current (fig. 1) IF(AV) 1.0 1.0 1.0 1.0 A
Peak forward surge current 8.3 ms single half sine-wave superimposed on rated load IFSM 30 30 30 30 A
Operating junction and storage temperature range TJ, TSTG -55 to +150 -55 to +150 -55 to +150 -55 to +150 °C

Deploying the ES1C in a PCB is made easy by its SMA (DO-214AC) case, which can be handled by pick-and-place machines effortlessly. It can, however, also be soldered by hand reasonably well.

Author: Tam Hanna
Published: March 12, 2021