| ??? 12/13/10 15:30 Read: times |
#180131 - Really small capacitances Responding to: ???'s previous message |
Erik Malund said:
Per is not mentioning one particular issue related to his title beyond this:
So reducing the voltage means less amount of energy to charge/discharge all capacitors with. So manufacturers really do want to drop the voltages. as an aillustration: if you have a 2.7-5.5V Vcc chip and run it at 5v you will save power by inserting a linear LDO regulator dropping the chip supply to 3V3 everything else being equal. Now, if you then replace the chip with an equivalent rated at 3V3 you will, due to the smaller geometry in the chip, save even more. re newly introduced 5V chips I believe that is the result of requests from USB device manufacturers wanting to save the regulator. Erik Yes, it follows from: Per said:
And lower voltages also means that the distance between features on the chip can be made smaller since the isolation required is lower. that smaller feature sizes means smaller capacitances. So the chip saves power both from smaller capacitances and from charging the capacitors to a lower voltage level. Smaller features not only gives less power consumption. It also gives basically "free" extra transistors to make smarter devices - todays processors have a large number of internal on/off switches allowing power to be cut to all features of the chip that isn't used. If you don't need the second UART, then it's no need to power up that UART or corresponding baudrate generator. And smaller features means that the bond areas and the size of input/output transistors will consume a significant percentage of the total size of the chip - adding an extra peripherial doesn't really much change the number of chips you can fit on a wafer. So we get super-integrated chips without huge prices. The Cortex-M3 core in 130nm technology is 0.74mm2 when optimized for speed and 0.38mm2 when optimized for size. So the transistors are cheap and the capacitances are small. |
| Topic | Author | Date |
| 5V ARMs | 01/01/70 00:00 | |
| 5V has its merits... | 01/01/70 00:00 | |
| The cost of protection? | 01/01/70 00:00 | |
| 5VDC | 01/01/70 00:00 | |
| You mean, "was" | 01/01/70 00:00 | |
| Voltage => power consumption | 01/01/70 00:00 | |
| re Voltage => power consumption | 01/01/70 00:00 | |
| RE: USB | 01/01/70 00:00 | |
| Really small capacitances | 01/01/70 00:00 | |
| unbound enthusiasm; USB & 5V? | 01/01/70 00:00 | |
| Trickle down of technologies | 01/01/70 00:00 | |
| yes..upps in the past | 01/01/70 00:00 | |
| toshiba cortex-m3 vcc=4.5..5V | 01/01/70 00:00 | |
| Special hardware protection of I/O? | 01/01/70 00:00 | |
5 volt Power supply | 01/01/70 00:00 |