The Ball Grid Array, BGA, uses the underside of the package, where there is a considerable area for the connections. SMD BGA Ball Grid Array package diagram. The pins are placed in a grid pattern (hence the name Ball Grid Array) on the under-surface of the chip carrier.
* The cerebellum (infratentorial or back of brain) is located at the back of the head. Its function is to coordinate voluntary muscle movements, and to maintain posture, balance and equilibrium. The cerebellum also affects emotions and higher-level cognitive functions.
Alternative Title: brain stem Brainstem, area at the base of the brain that lies between the deep structures of the cerebral hemispheres and the cervical spinal cord. The brainstem is divided into three sections in humans: the midbrain (mesencephalon), the pons (metencephalon), and the medulla oblongata (myelencephalon). The brainstem is a sort of automatic control centre for several important involuntary actions of the body, such as heartbeat, breathing, blood pressure, and many reflexes.