Can I Limit the depth of a Generic Stack?

public static void Trim<T> (this Stack<T> stack, int trimCount)
    {
        if (stack.Count <= trimCount)
            return;

       stack = new
            Stack<T>
            (
                stack
                    .ToArray()
                    .Take(trimCount)
            );
    }

class DropOutStack<T>
{
	private T[] items;
	private int top = 0;
	public DropOutStack(int capacity)
	{
		items = new T[capacity];
	}

	public void Push(T item)
	{
		items[top] = item;
		top = (top + 1) % items.Length;
	}
	public T Pop()
	{
		top = (items.Length + top - 1) % items.Length;
		return items[top];
	}
}