(2) [DC Analysis, 20 points] The following shows the DC characteristic curve of an
inverter INV ($V_1$ is a constant). Draw a DC characteristic curve of a buffer
consisting of two INVs.
(3) [Noise Analysis, 40 points]
$V_1 = [a, b]$
$V_2 = [c, d]$
The schematic shown above shows a circuit consisting of two inverters (INV1 and
INV2). $V_1$ and $V_2$ are independent noise sources. The ranges of $V_1$ and $V_2$ are [a, b] and
[c, d], respectively ($a, c < 0$, $b, d > 0$). $V_{out}$ should be 0V for input voltage 0V and 1V for
input voltage 1V. Find the maximum value of (25b - 15c) and the minimum value of
(25a - 15d) when Char1 is for INV1 and Char2 is for INV2.
