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All right, let's get moving. Good morning. Let me take a quick poll. So, how many of you have completed Lab 4. Completed Lab 4? Wow, that's great. So, how many people have begun Lab 4? OK, well that's good.

I won't ask the last question. OK so, well I hope you're having fun with this lab. Lab 4 was designed to be almost like a mini-project. And, it sort of ties together a lot of the content of the entire course.

And, it's not unlike the kind of systems that people design in industry, in systems that go into a variety of devices like, say, for example, digital CD players and stuff like that. A lot of mixed signal stuff goes in.

OK, so today, I'm going to continue with our discussion of energy and CMOS. CMOS will be a new topic that I will introduce. So, the last lecture, we spent a fair bit of time talking about energy, and how to compute the energy of our inverter.

So, let me start from where I left off, and I've given you a couple of extra pages of notes today just to sort of tie it to the previous lecture. Right now, I'm going to start off on page three. So, what we saw last time was an inverter of this sort, Vs, VIN, and we said, let's study the situation where this inverter was driving a load capacitor, C.

Where did this load capacitor come from? Well, this inverter could be driving one, or two, or three, or four other larger gates, OK? So, this C is lumped value of the gate capacitances of all of those inverters.

This may also include some component due to wiring capacitance and stuff like that. So, for an inverter like this, we showed in the last lecture that the formula for the average power was, so this was a static power independent of frequency, and this was called dynamic power, and it had some bearing, it's related to the frequency at which you clocked your circuit.

So, this was related to standby power, and this to dynamic. So, what I also said is that I gave you a bunch of numbers so you could compute the power consumption of a chip that included 10^8 gates, 100 million gates, and at a frequency of 1 GHz, and a bunch of other numbers.

C was given to be 0.1 femtofarads. Femto is 10^-15. So, F was 10^9. VS was 5V, and for these numbers, if you plonk them down in something like this, for 10^8 gates on a chip, the average power would be 10^8 times these two.

So, this would be five squared, which is 25, divided by twice. RL was given to be 10 kilo-ohms, so, twice, 10^4. And here we had CVS^2. So, C was 10^-16, 0.1 femtofarads. Vs^2 was 25, and F was 10^9.

So, if you commence through the numbers here, what you end up getting is something that looks like this, 10^8 times this guy here. This is 1.25mW plus this guy ends up being 2.5 microwatts. So, this should come as a bit of a shocker.

If I take 1.25mW, and multiply that out by 10^8, this says that each gate suffers a standby power loss of 1.25mW. So times 10^8, I get 125kW, and this guy yields 250W. OK, the 250W is manageable. It's still high, and just so you don't think that this is unreasonable, when the Pentium 4 first came out, it was consuming 170W of power.

OK, you should see the heat sinks on there. There's actually a huge heat sink with a fan built into the top of the heat sink. OK, today it's down to more reasonable numbers like 100W and so on, but when it came out it was in this range.

So it's high but not unreasonable. But this, of course, is totally wacko. OK, imagine carrying a laptop around, and the sucker is blowing 125kW. That'll be fun.

I won't ask the last question. OK so, well I hope you're having fun with this lab. Lab 4 was designed to be almost like a mini-project. And, it sort of ties together a lot of the content of the entire course.

And, it's not unlike the kind of systems that people design in industry, in systems that go into a variety of devices like, say, for example, digital CD players and stuff like that. A lot of mixed signal stuff goes in.

OK, so today, I'm going to continue with our discussion of energy and CMOS. CMOS will be a new topic that I will introduce. So, the last lecture, we spent a fair bit of time talking about energy, and how to compute the energy of our inverter.

So, let me start from where I left off, and I've given you a couple of extra pages of notes today just to sort of tie it to the previous lecture. Right now, I'm going to start off on page three. So, what we saw last time was an inverter of this sort, Vs, VIN, and we said, let's study the situation where this inverter was driving a load capacitor, C.

Where did this load capacitor come from? Well, this inverter could be driving one, or two, or three, or four other larger gates, OK? So, this C is lumped value of the gate capacitances of all of those inverters.

This may also include some component due to wiring capacitance and stuff like that. So, for an inverter like this, we showed in the last lecture that the formula for the average power was, so this was a static power independent of frequency, and this was called dynamic power, and it had some bearing, it's related to the frequency at which you clocked your circuit.

So, this was related to standby power, and this to dynamic. So, what I also said is that I gave you a bunch of numbers so you could compute the power consumption of a chip that included 10^8 gates, 100 million gates, and at a frequency of 1 GHz, and a bunch of other numbers.

C was given to be 0.1 femtofarads. Femto is 10^-15. So, F was 10^9. VS was 5V, and for these numbers, if you plonk them down in something like this, for 10^8 gates on a chip, the average power would be 10^8 times these two.

So, this would be five squared, which is 25, divided by twice. RL was given to be 10 kilo-ohms, so, twice, 10^4. And here we had CVS^2. So, C was 10^-16, 0.1 femtofarads. Vs^2 was 25, and F was 10^9.

So, if you commence through the numbers here, what you end up getting is something that looks like this, 10^8 times this guy here. This is 1.25mW plus this guy ends up being 2.5 microwatts. So, this should come as a bit of a shocker.

If I take 1.25mW, and multiply that out by 10^8, this says that each gate suffers a standby power loss of 1.25mW. So times 10^8, I get 125kW, and this guy yields 250W. OK, the 250W is manageable. It's still high, and just so you don't think that this is unreasonable, when the Pentium 4 first came out, it was consuming 170W of power.

OK, you should see the heat sinks on there. There's actually a huge heat sink with a fan built into the top of the heat sink. OK, today it's down to more reasonable numbers like 100W and so on, but when it came out it was in this range.

So it's high but not unreasonable. But this, of course, is totally wacko. OK, imagine carrying a laptop around, and the sucker is blowing 125kW. That'll be fun.

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