A federal grand jury here will decide next week whether to bring criminal charges against a former aide to Sen. Herman E. Tamadge (D-Ga.) for obtaining $2,289 in nonexistent Senate expenses.

The grand jury, which sources said has been meeting since last fall on the entire finanical misconduct case surrounding Talmadge, must decide by Wednesday whether to indict Daniel Minchew for the false expense claim.

Minchew, who was Talmadge's chief aide from 1971 to 1974, has acknowledged placing both the $2,289 Senate expense check and another Senate payment for $10,604 into a secret account he set up in the Riggs National Bank. He has insisted, however, that all the money be subsequently got from the account was for legitimate expenses he incurred on Talmadge's behalf.

Federal sources said the five-year statute of limitations on any prosecution for the larger check has already expired. But the sources said the grand jury has until Wednesday to act on the $2,289 check.

In a related action, the Senate Select Committee on Ethics yesterday received a formal report from special counsel Carl Eardley calling for sanctions against the Georgia senator. Last week, in closed session, Eardley urged the committee to press the full Senate for a censure action against Talmadge.

The Ethics Committee will not issue its final report until at least September, a committee staff assistant said yesterday. The assistant said the ethics panel will meet in closed session next Wednesday to review Eardley's report. At least four of the six committee members must approve any recommendation to the Senate of disciplinary action against Talmadge.