7 weeks, baby should be sleeping more in the day and awake for feedings at night. 5 hours at a time is considered good but most babies don't sleep that.
At seven weeks old an infant may not have yet developed a pattern of sleeping and waking hours. As the child ages they will defiantly start sleeping in more uniform periods.
Typically a seven week old infant will sleep for up to four hours each time he is layed down and may only stay awake for two. However, infants needs vary since we are not all alike and it is possible that yours will sleep less. Or he may sleep more.
At 7 weeks of age, babies don't really have much of a pattern. They usually will sleep for a while after eating, but it's not common for them to have a schedule until they are a few months old.