With the acquittal of McAfee’s former general counsel, one might think the stock option backdating wave in the Northern District of California will ebb.

Then again, an investigation surrounding Trident Microsystems Inc. appears to be cresting.

Securities and Exchange Commission lawyers in Washington, D.C. — along with a Northern District federal prosecutor — are taking a hard look at whether to bring cases against former executives of the Silicon Valley chip maker, say several lawyers familiar with the investigation.

The Justice Department’s involvement came as a summer surprise to some of the company’s former executives. After internal investigators from Morrison & Foerster questioned many of the relevant players, a handful of finance and HR executives submitted to SEC interviews last year without asserting their Fifth Amendment rights, lawyers say. This came after the company’s former CEO, Frank Lin, resigned; He was eventually fingered in securities filings for “significant involvement” in backdating.

Yet those interviews with the government have raised a classic tension in the white-collar practice: cooperate early with the SEC to show good faith, balanced against the risk of heightened scrutiny of those statements for any contradictions.

Defense lawyers fear the SEC is moving toward issuing Wells notices to some of those interviewed. The Washington, D.C., investigator on the case, Margaret McGuire, did not return phone calls.

Whether or not to take the Fifth Amendment is ultimately up to the client, said Seth Aronson, an O’Melveny & Myers partner in Los Angeles who is not involved in Trident. But the legal advice is a very tough judgment, he said.

“Every lawyer grapples with that. It really depends on where your client fits into the overall picture,” Aronson said. “There’s no right or wrong answer here.”

When Assistant U.S. Attorney Thomas Stevens began his own investigation this past summer, a few executives who had already talked to the SEC — including some who had been sharing the same lawyer, Howard Rice Nemerovski Canady Falk & Rabkin partner Sarah Good — scrambled to find their own white-collar counsel to do damage control, attorneys said.

Good declined to comment, saying Howard Rice media policy dictated that she can’t discuss clients and ongoing litigation “unless the client has specifically asked us to do so.”

It is unclear whether a criminal case will be brought against anyone from the company; U.S. Attorney spokesman Josh Eaton wouldn’t talk about Trident. Stevens joined the Northern District’s securities fraud unit in February, Eaton said, from the fraud section at main Justice.

Even if any Trident executives gave problematic SEC interviews, several lawyers involved in the case say it was Lin who closely controlled the company — including its stock administration program — with the help of his assistant.

The former CEO immigrated to the United States and launched Santa Clara, Calif.-based Trident in 1987. The company eventually found a niche producing chips for LCD televisions. Its stock traded in the teens as recently as last year, but has since fallen below $2 amid growing commoditization in the business.

The company was one of those highlighted in The Wall Street Journal‘s backdating exposes. According to securities filings, a special board committee eventually determined that a huge swath of Trident’s options — 57 percent between 1992 and 2006 — had been handled improperly.

However, Trident is hardly a Valley titan: It restated $52 million because of backdating, less than other companies with backdating problems scrutinized by the Justice Department. Apple restated $84 million, and KLA-Tencor Corp. restated $370 million; No executives from those companies have faced criminal charges.

And while lawyers familiar with Trident’s options practices describe the compliance regime at the company as nonexistent (the company had no general counsel position until after the scandal broke), some of the conduct under scrutiny resembles what happened at other companies across the Valley. For instance, employees would routinely be added into option pools, after the fact, that carried favorable dates.

Trident has historically been represented by Gray Cary, and still has DLA Piper working on its backdating litigation. DLA partner David Gross declined to comment.

Lin resigned in 2006, along with his assistant Carmen Chang, who lawyers said regularly executed her boss’s options directives. She also resigned from Trident. Both are said by lawyers with knowledge of the investigation to have asserted their Fifth Amendment rights with the SEC, but Lin’s attorney, Shearman & Sterling partner Patrick Robbins, declined to comment, as did Chang’s attorney, Nanci Clarence of Clarence & Dyer.

Government action against other Trident executives may depend on whether any problems with their statements to the SEC are overwhelming or picayune. Speaking in general, white-collar lawyers say the sheer volume of the government’s backdating docket incentivizes executives to go in and talk. If they can convince the SEC that what happened at their company was so-called routine backdating — as opposed to more blatant self-enrichment — often the government will issue a pass.

In addition, taking the Fifth can cause the SEC to look at an individual even more closely.

But talking to the government, without a full view of the evidence, gives many a white-collar lawyer pause. Should a client’s story appear contradictory, it could fuel a government investigation, because such discrepancies are often used to good effect to prove intent before a jury.

One of the finance department executives who departed the company because of backdating, former accountant Peter Jen, talked to the SEC and had been represented by Good until this past summer, lawyers said. According to court filings, his current lawyer is Ukiah, Calif., solo Ann Moorman. She was out of the office this week.

Another ex-client of Good’s, former president J.H. Chang, landed with Edward Swanson of Swanson, McNamara & Haller, who declined to comment.

Once a client does decide to talk without taking the Fifth, preparation must be extensive, Aronson said. No documents or questions should come as a surprise.

“These games are won in the locker room before you get on the field,” he said.