RF to IF Mixers by IDT: Low-power Downconversion Mixers with Zero-Distortion

Hello, my name is Chris Stephens. I'm the Director of Marketing for RF products here at IDT. I'm going to take a little of your time to describe zero distortion technology and its benefits for dual mixers.

 

First disclaimer, programming note, performance claims described herein are based on EVkit measurements in our lab or final test measurements in our test bed. Performance claims for our competing products are based on the Typ Ops curves from their publicly available data-sheets. When we talk about operation to 100 degrees C reliable operation, you can read the list of the JEDEC standards that we qualify our devices to there.

 

What is this zero distortion technology? It's a major performance improvement for mixers. It practically eliminates intermodulation products. It also has a benefit that it has a significant reduction in power consumption for the mixers. A side benefit is that with such high intercept point the optimization effort is much simplified, because there's lots of extra margin for type approval. Another way to leverage it is you can raise the average frontend gain, and this approves the SNR for all users on the cell periphery. It's important to note that we've qualified these devices to 100 degrees Celsius continuous operation. Zero distortion technology was developed right here in Westford, Massachusetts.

 

The key benefit is what I'm going to describe here, the spectral graph on the upper left is a representation of the crowded spectrum in the U.S. that would be to say the USPCS spectrum. You've got 2G GSM users and 3G W-CDMA users in the same spectrum. All that gets into the antennae and the mixer is the pressure point for the intermodulation response. Most of the intermodulation response of the radio card receiver comes from the mixer. IDT's mixer reduces the unwanted third order intermodulation energy by 98%, that's 19 decibels versus competing devices.

 

If you zoom in a little closer, what you see here is that the red lines are the intermod products that spill over into the 3G user’s bandwidth. If that user’s far away, there would be very little of that transit power getting back into the base, from the handset getting back into the base station receiver. The

intermodulation energy from the close in 2G users would swamp that 3G users spectrum. That's what it looks like if you zoom in even further with a standard mixer from one of our competitors. If you replace that mixer with our device, you can see the total intermodulation energy at the system level again, this is assuming a generic base station system, is reduced by 83%. This frees up that spectrum, and improves coverage and enhances the quality of service. Again, it's important to note these devices are in volume production now.

 

There are three main versions of the device that cover 700 to 2700 megahertz. What I'm showing here are some of the performance curves for intermodulation performance, as specified by output IP3, which is the typical industry standard metric for talking about intermodulation performance. The top left graph shows our flagship product, the F1152, that's a PCS, DCS, UMTS dual mixer. At about 1.65 watts of power consumption, it has about ten dB better than a competitor's popular offering. To the right I show our TDD, LTE mixer in the 2.3 to 2.7 gigahertz bands. It's got about 39 dBm of output IP3, which is seven or so dB better than another popular offering from one of our competitors, at 800 milliwatts less power consumption. Then, on the lower left graph I show, if we take that same device and configure it for what we call standard mode of operations, instead of low current mode, we can get another improvement of up to 42 or 43 dBm output IP3. We can do that with only an increase in power consumption of 500 milliwatts, still less, by 250 milliwatts, than the competitor's offering. It's important to know from these graphs also that the performance at 100 degrees Celsius is actually even better than at room temperature. You can see the actual performance at 100 degrees Celsius is about 45 dBm output IP3.

 

Another thing that I want to make sure to convey to you is that we test intercept point in production, and the zero distortion technology is very robust. Here, I show the distribution for our flagship F1152 product for intercept point tested in production. You can see that the distribution is very tight and between 42 and 45 dBm. We set our test limit at 40 dBm. No product will go to customers that's worse than 40 dBm. We have a very tight distribution.

 

The products, the zero distortion products is what I'm going to talk about now, are the F1100 series mixers. These products are the market leader in output IP3, power consumption, LO pulling spec and usable IF bandwidth. Just three versions of these will cover 700 to 2700 megahertz. The popular UTRA bands. Again, these are pin compatible with popular offerings from Skyworks and Maxim.

 

The availability of the F1162 was announced very recently. The F1152 was announced in March. The F1150 in September 2011. Shortly we'll be announcing the F1100 and the F1102. Final samples of all devices are available now.

 

There's other aspects to a mixer aside from its intercept point that are important. I'm going to take you through a few of these here. Here I'm showing the noise figure of the F1162, which is our LTE/TDD product for the 2.3 to 2.7 gigahertz bands. You can see it's about nine and a half dB at 2.5 gigahertz, which is very competitive and very good.

 

The spur rejection, the dreaded half IF or two by two spur rejection, you can see here it's better than minus 70 dBc across the bed. 

 

The one-dB compression in standard mode, it's about 12 and a half. Of course in low current mode it's reduced a little bit for the lower current, and that's about 10.3 to 10.40 dBm of one-dB compression.

 

Finally, channel isolation is very important. The F1162 2.3 to 2.7 gigahertz mixer is shown here. Better than 55 decibels of channel A to channel B isolation for the dual mixer.

 

Another unique feature we've included in this device is what we call a robust standby mode. In TDD systems, you can power the mixer down in unused TDD slots. It can recover, it might be hard to see there, but it recovers in 150 nanoseconds and the LO port impedance is essentially unchanged as shown here. The change in return loss is about a tenth of a decibel. That keeps the LO that's hooked to it from being pulled and makes an efficient scheme to save more power in addition to the very low power consumption the device already offers in TDD systems.

 

This is a picture of the EVkit and how it's operated for the F1100 series. The EVkit is designed to be instantly configurable for other low current mode, again, which is at about 1.15 watts or standard mode with 1.65 watts.

 

 IDT's sales team will offer excellent app support for you when you design this product in. Here's a page from our compatibility design that shows the common schematic to use both Skyworks and IDT in the same footprint. Just the schematic, the value changes, necessary to use IDT versus Skyworks. This is just one example of the kind of information included in our compatibility design, and the kind of app support we will give you while you're designing this product in.

 

In summary, IDT's zero distortion mixers are a compelling pin-compatible upgrade for your design. You can contact your IDT sales professional just about anywhere in the world or your local authorized distributor. Or simply email Rfsupport@IDT.com and request samples and collateral today. Thank you.