Donovan McNabb Sentenced to 18 Days In Jail ... In DUI Conviction

Donovan McNabb was just sentenced to 18 days in jail ... after pleading GUILTY to DUI in his June 28th arrest in Arizona ... TMZ Sports has learned.

Court officials confirm .... the ex-NFL quarterback received the following sentence:

-- 18 days in county jail

-- 72 days in home detention after jail

-- 30 hours of community service

-- Counseling after home detention

-- Unsupervised probation until he completes the sentence

-- ordered to pay a $6,342.23 fine

McNabb's attorney Thomas Connelly tells us the QB was granted a "work release"during his jail sentence ... which means he'll spend his nights behind bars and days out working in the free world. Unclear what his day job will be. He has to report to jail by the end of November.

Connelly says McNabb has already completed 16 hours of alcohol counseling and insists that Donovan "already does hundreds of hours of community service each year so 30 will be no problem."

As we previously reported, McNabb was arrested in Gilbert, AZ after crashing into a car stopped at a red light.

After the crash, cops say his blood alcohol level was .17 -- more than DOUBLE the legal limit.

Cops also found a bottle of tequila in his trunk.

At the time of the arrest, McNabb admitted he had been at a bar earlier in the night but said he wasn't drunk. When asked about the suspicious scent on his breath, McNabb told cops he had been taking cold medicine before the crash and had been sucking on cough drops.

It was the 2nd time McNabb has been convicted of DUI in 2 years ... the first incident happened in 2013 and McNabb served 1 day in jail.

Story developing ...