afs600 Actel Corporation, afs600 Datasheet - Page 93

• Manufacturer Part Number: afs600
• Description: Actel Fusion Programmable System Chips Mixed-signal Family With Optional Arm Support
• Manufacturer: Actel Corporation

Terminology
BW is a range of frequencies that a Channel can handle.
A channel is define as an analog input configured as one
of the Prescaler range shown in
page
and the ADC.
Channel Gain is a measured of the deviation of the
actual slope from the ideal slope. The slope is measured
from the 20% and 80% point.
Channel Gain Error is a deviation from the ideal slope of
the transfer function. The Prescaler Gain Error is
Figure 2-68 • Total Channel Error Example
BW – Bandwidth
Channel
Channel Gain
Channel Gain Error
2-115. The channel includes the Prescaler circuit
Gain
=
Gain
----------------------- -
Gain
C hannel Input
O ffset Er r or
actual
ideal
In p u t V o lta g e to P re sca le r
Table 2-54 on
A d v an c ed v1 . 4
T otal C hannel Er r or
C hannel G ain
Actual Output
expressed as the percent difference between the actual
and ideal, as shown in
Channel Offset error is measured as the input voltage
that causes the transition from zero to a count of one.
An Ideal Prescaler will have offset equal to ½ of LSB
voltage. Offset error is a positive or negative when the
first transition point is higher or lower than ideal. Offset
error is expressed in LSB or input voltage.
Total Channel Error is defined as the total error
measured compared to the ideal value. Total Channel
Error is the sum of gain error and offset error combined.
Figure 2-68
Total Channel Error is defined as the difference between
the actual ADC output and ideal ADC output. In the
example shown in
would be a negative number.
Channel Input Offset Error
Total Channel Error
shows how Total Channel Error is measured.
Actel Fusion Programmable System Chips
Error
Figure
Gain
EQ
=
2-1.
(1-Gain) 100%
2-68, the Total Channel Error
×
EQ 2-1
2-79