Rainbow Electronics ADC1241 - Manual (Page 5)

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
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