Affirma Spectre DC Device Matching Analysis Tutorial - Cadence ...

Affirma Spectre DC Device Matching Analysis Tutorial
ΔIdsi -- is the mismatch current of the i MOSFET,
th
mi -- is incidence column vector that maps the mismatch current of the ith device to
the proper MNA equations.
The output is defined as:
, (EQ 6)
where y is a column vector and superscript “T” represents the transpose.
In terms of (6), the sensitivity becomes:
∂x
The term ---------------- is obtained by differentiating (5) with respect to ΔIds --
∂ΔIds
i
i
and then solving
Vout y T = x
∂
T x
Vout y . (EQ 7)
∂ΔIdsi
∂
= ----------------
∂ΔIdsi
∂ f( x)
∂x
-------------- ---------------- + m , (EQ 8)
∂x
∂ΔIds
i = 0
i
∂x
∂ f( x)
---------------- = – --------------
∂ΔIdsi
∂x
Combining (9) with (7), the expression for sensitivity becomes:
∂
∂ΔIdsi
Vout – y
T f x ( ) ∂
=
--------------
∂x
– 1
mi . (EQ 9)
– 1
mi Since there is only one output and many MOSFETS, it is efficient to define a
(EQ 10)
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