"'Don't catch a falling knife' ... The idea of buying a former superstar stock at a discount price certainly has its attractions, but you've got to make sure you catch the haft -- not the blade."

So runs the thesis of my recurring Fool column "Get Ready for the Bounce," in which we search among the wreckage of Mr. Market's overturned cutlery drawer, hoping to find future winners in a pile of 52-week losers. But do we really need to sit around for a whole year, waiting for a potential bouncer?

I say nay. Sometimes, stocks fall far in far less time than a year -- and like a superball dropped from the balcony, the harder they fall, the higher they bounce. Today, we're going to look at a few equities that've suffered dramatic drops over the past week. With a little help from the 140,000 members of Motley Fool CAPS, we hope to find an opportunity or two for you:

Stock

How far from 52-week high?

Recent Price

CAPS Rating
(out of 5)

ON Semiconductor  (NASDAQ:ONNN)

(7%)

$8.52

*****

Trina Solar  (NYSE:TSL)

(13%)

$29.07

**

VIVUS Inc (NASDAQ:VVUS)

(10%)

$11.06

**

Fifth Third Bancorp (NASDAQ:FITB)

(53%)

$9.78

**

Vanda Pharmaceuticals

(14%)

$14.26

*

Companies are selected by screening on finviz.com for abrupt 5% or greater price drops over the past week. 52-week high and recent price data provided by finviz.com. CAPS ratings from Motley Fool CAPS.

Five super falls -- one superball
Last week was a rough one for these five stocks, and Friday in particular treated them harshly. But why? Look all you want, but I doubt you'll find anything qualifying as "bad news" for any of these companies. To the contrary, most of them started the week strong -- before finishing weak.

Take Vanda Pharmaceuticals for example. Up 15% Thursday on no news, it shed 6% Friday on ... no news. VIVUS? It leapt 71% Wednesday in response to reports that its obesity drug may outclass competing products from sanofi-aventis (NYSE:SNY) and Arena, but the stock tanked 7% Friday for no particular reason. Likewise with Fifth Third Bancorp, and just as likewise with Trina (whose stock had risen earlier in the week when First Solar gave the whole solar sector a boost.)

Aside from their ill-fated stocks, though, these companies all have one other thing in common: They're loathed by CAPS members -- with one exception. Which of these stocks is not like the others?

ON Semiconductor 
bubbasuth praised ON earlier this summer for its "portfolio of diverse semiconductor products, some of them unique. Many legacy parts are still used and now only available from a few suppliers such as ON, yet they also provide technologies at the forefront of new product development."

Speaking of forefronts, Rico52 especially likes ON's role as "a leader in distribution of chips for China & SE Asia. ... With a P/E of 3.89 this stock has only one direction." (Er, that is... it had only one direction until Friday.)

The real secret to ON's volatility can be found in two words: Jim Cramer. It appears the Baron of Booyah may have played a part in pushing ON up prior to last week's decline. Garyestein fills us in on the details:

This is part of the mobile Internet index that Cramer is touting ... His thesis is that the mobile Internet [will] be as big a game changer as the original Internet was. Being a CTO I do not think it will be that big a movement ... What your looking at is replacing every cell phone and laptop with a device that can connect to the Internet at broadband speeds form just about anywhere in the US. The only problem I [have] with his choice is that he left out [Hewlett-Packard (NYSE:HPQ)] and [DELL (NASDAQ:DELL)] and Lenovo ...

Here at the Fool, we love kidding Cramer. But today I'm going to adopt a more serious tone. Why? Because the truth is that I greatly fear the Goateed Guru is leading investors astray with regard to ON.

Now, I'm not talking about the P/E. ON hasn't earned a single red cent in nine months, and shows a loss for its trailing-12-month results. But the situation isn't really as bad as that. In fact, ON is generating significant free cash flow from its business -- $215 million during the same period that it's shown a GAAP loss. The problem is that even this grand sum is too little to distract me from other fundamental uncertainties.

With a market cap of $3.6 billion, ON currently sells for 16.7 times its free cash flow. That's not an absurd valuation. But relative to analyst expectations of sub-12% five-year growth going forward, it's just not enough to justify the stock's price -- the more so when you factor in the company's debt-heavy balance sheet, which pushes ON's enterprise value even higher.

Foolish takeaway
Is the "mobile Internet" truly "The Future?" I'll defer to Garyestein and the other technophiles in our ranks on that question.

If their answer's "yea," then perhaps ON will grow faster than Wall Street analysts think. My problem with the stock is simply this: Based on ON's stock price, it looks like investors are assuming: (1) that the mobile Internet is where we're heading, and (2) that ON is the way to play the trend. To which I would reply:

Two hypotheticals do not a certainty make. Neither do they make this overpriced stock a bargain.

(Buy hey, feel free to disagree. If you know more than I do about the company, don't keep it to yourself: Tell us why ON Semiconductor's a buy.)

Motley Fool CAPS : It's fun, it's free, and it just might make you famous.

First Solar is a Motley Fool Rule Breakers recommendation. Dell is an Inside Value pick.

Fool contributor Rich Smith does not own shares of any company named above. You can find him on CAPS, publicly pontificating under the handle TMFDitty, where he's currently ranked No. 598 out of more than 140,000 members. The Fool has a disclosure policy.