3 ms·

Beautiful pics. I wonder why, in a few places, there are pairs of bonding wires connecting the same pads.

• FPGAhacker 5y ago
  I’m speculating but when I’ve seen it in the past it was for handling higher current. In this case I’m wondering if it’s used to maintain better control of the voltage gradient on a pad.
  • ejiblabahaba 5y ago
    Sometimes it's to handle higher currents, other times it's to reduce the bond wire inductance and improve the high-frequency response. For power pins it can be both. Especially for a multi-chip module with some digital circuitry, there's potential for high-frequency digital transients that need nearby decoupling capacitors through low-inductance loops, or the transistor switching noise can pollute other copackaged circuit supplies; amplifiers also benefit from lower inductance on the supply lines since it stabilizes the frequency response at higher offsets beyond the loop bandwidth of any integrated supply regulation, current sources, bandgap references etc. So you're essentially correct, it's about voltage gradients, but probably at higher frequency.
• magicalhippo 5y ago
  > Beautiful pics. He uses[1] Helicon Focus[2] for focus stacking. A lot of these die shots are pieces of art, and also quite interesting. I especially like the LTZ1000 voltage reference[3] or the Thyracont Inclinos[4] which is an accelerometer without moving parts. A lot of the MEMS dies are also very interesting, because of their moving parts, like this[5] ADXL213. [1]: https://www.eevblog.com/forum/projects/transistors-die-pictures/msg3546374/#msg3546374 https://www.eevblog.com/forum/projects/transistors-die-pictu... [2]: https://www.heliconsoft.com/heliconsoft-products/helicon-focus/ https://www.heliconsoft.com/heliconsoft-products/helicon-foc... [3]: https://www.richis-lab.de/REF03.htm https://www.richis-lab.de/REF03.htm [4]: https://www.richis-lab.de/MEMS_04.htm https://www.richis-lab.de/MEMS_04.htm [5]: https://www.richis-lab.de/ADXL213.htm https://www.richis-lab.de/ADXL213.htm