4 ms·

I'm amazed at how fast things moved in the computer industry. Per the article, FETs only just began to work in 1960, but by 1964 Seymour Cray at CDC was complet

by fernly 8y ago

I'm amazed at how fast things moved in the computer industry. Per the article, FETs only just began to work in 1960, but by 1964 Seymour Cray at CDC was completing the 6600[1], a "supercomputer" with massive numbers of them. [1] https://en.wikipedia.org/wiki/CDC_6600 https://en.wikipedia.org/wiki/CDC_6600

dbcurtis 8y ago
I'm pretty sure the 6600 was done in 10K ECL, which was a bipolar technology, not FET. In ECL, the transistors are biased such that they never saturate, which decreases switching time at the expense of power consumption. Also, the inputs are configured as a diff-amp, which helps switching speed also. Some time after the 6600 (1980's) I was a logic designer working in 100K ECL and compatible gate arrays (144 transistors per chip). Each gate array required 5 Watts of cooling. We had one 20,000 BTU Ton water chiller for the CPU, and that was the design-limiting constraint.
- squarefoot 8y ago
  I have next to none experience with ECL chips, but recall in the 80s the 11C90 ECL divider which was the only affordable choice if one needed a prescaler for his frequency counter to measure frequencies of several hundred MHz. That chip ran hot compared to other TTL ones, but a few years on, probably late 80s, I used a 8 pin DIL ECL chip for a PLL (can't remember the name) which I recall running much cooler than the 11C90. They probably improved the technology before it got surpassed by more modern ones.
cnasc 8y ago
If large numbers of FETs are your thing, you might be interested in The Beast with a Thousand JFETs [1], a discrete audio amplifier dissipating about 140 watts per channel and producing output power of 70 watts with a 2 ohm load. Other articles/designs by Nelson Pass are certainly interesting as well. I'm not much of one for audiophile stuff, but he has a knack for interesting designs. [1] http://www.firstwatt.com/pdf/art_beast.pdf http://www.firstwatt.com/pdf/art_beast.pdf

by fernly 8y ago

dbcurtis 8y ago

I'm pretty sure the 6600 was done in 10K ECL, which was a bipolar technology, not FET. In ECL, the transistors are biased such that they never saturate, which decreases switching time at the expense of power consumption. Also, the inputs are configured as a diff-amp, which helps switching speed also. Some time after the 6600 (1980's) I was a logic designer working in 100K ECL and compatible gate arrays (144 transistors per chip). Each gate array required 5 Watts of cooling. We had one 20,000 BTU Ton water chiller for the CPU, and that was the design-limiting constraint.

squarefoot 8y ago
I have next to none experience with ECL chips, but recall in the 80s the 11C90 ECL divider which was the only affordable choice if one needed a prescaler for his frequency counter to measure frequencies of several hundred MHz. That chip ran hot compared to other TTL ones, but a few years on, probably late 80s, I used a 8 pin DIL ECL chip for a PLL (can't remember the name) which I recall running much cooler than the 11C90. They probably improved the technology before it got surpassed by more modern ones.

cnasc 8y ago

If large numbers of FETs are your thing, you might be interested in The Beast with a Thousand JFETs [1], a discrete audio amplifier dissipating about 140 watts per channel and producing output power of 70 watts with a 2 ohm load. Other articles/designs by Nelson Pass are certainly interesting as well. I'm not much of one for audiophile stuff, but he has a knack for interesting designs. [1] http://www.firstwatt.com/pdf/art_beast.pdf http://www.firstwatt.com/pdf/art_beast.pdf