
AC Electrical Characteristics (Continued)
Note 7: A diode exists between AV
CC
and DV
CC
as shown below.
TL/H/10554–4
To guarantee accuracy, it is required that the AV
CC
and DV
CC
be connected together to a power supply with separate bypass filters at each V
CC
pin.
Note 8: Accuracy is guaranteed at f
CLK
e
2.0 MHz. At higher and lower clock frequencies accuracy may degrade. See curves in the Typical Performance
Characteristics Section.
Note 9: Typicals are at T
J
e
25
§
C and represent most likely parametric norm.
Note 10: Limits are guaranteed to National’s AOQL (Average Outgoing Quality Level).
Note 11: Positive linearity error is defined as the deviation of the analog value, expressed in LSBs, from the straight line that passes through positive full scale and
zero. For negative linearity error the straight line passes through negative full scale and zero. (See
Figures 1b
and
1c
).
Note 12: The ADC1241’s self-calibration technique ensures linearity, full scale, and offset errors as specified, but noise inherent in the self-calibration process will
result in a repeatability uncertainty of
g
0.20 LSB.
Note 13: If T
A
changes then an Auto-Zero or Auto-Cal cycle will have to be re-started, see the typical performance characteristic curves.
Note 14: After an Auto-Zero or Auto-Cal cycle at the specified power supply extremes.
Note 15: If the clock is asynchronous to the falling edge of WR
an uncertainty of one clock period will exist in the interval of t
A
, therefore making the minimum t
A
e
6 clock periods and the maximum t
A
e
7 clock periods. If the falling edge of the clock is synchronous to the rising edge of WR then t
A
will be exactly 6.5 clock
periods.
Note 16: The CAL
line must be high before any other conversion is started.
Note 17: The specifications for these parameters are valid after an Auto-Cal cycle has been completed.
Note 18: A military RETS electrical test specification is available on request. At time of printing, the ADC1241CMJ/883 RETS specification complies fully with the
boldface limits in this column.
TL/H/10554–5
FIGURE 1a. Transfer Characteristic
5
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