Oh dear, the notorious Dinosauroid. That model darkened pretty much every piece of dinosaur literature in the early-to-mid '90s.
Troodon was an exceptional animal, though. Does indeed have one of the very largest brains-for-body-size known among dinosaurs (though, again, it's closely related to birds), and it was unusual among dinosaurs as it was adapted for a nocturnal lifestyle. Superb nightvision, and in northern regions with long periods of darkness, they grew a bit larger and became the dominant predator.