M1AFS600-PQ208 Datasheet, PDF (144/334 Pages) Microsemi Corporation – Fusion Family of Mixed Signal FPGAs

Device Architecture
Similarly,
Min. Output Voltage = (Max. Negative input offset) + (Input Voltage x Max. Negative Channel Gain)
= (–88 mV) + (5 V x 0.96) = 4.712 V
Calculating Accuracy for a Calibrated Analog Channel
Formula
For a given prescaler range, EQ 31 gives the output voltage.
Output Voltage = Channel Error in V + Input Voltage
where
Channel Error in V = Total Channel Error in LSBs x Equivalent voltage per LSB
Example
Input Voltage = 5 V
Chosen Prescaler range = 8 V range
Refer to Table 2-52 on page 2-126.
EQ 31
Max. Output Voltage = Max. Positive Channel Error in V + Input Voltage
Max. Positive Channel Error in V = (6 LSB) × (8 mV per LSB in 10-bit mode) = 48 mV
Max. Output Voltage = 48 mV + 5 V = 5.048 V
Similarly,
Min. Output Voltage = Max. Negative Channel Error in V + Input Voltage = (–48 mV) + 5 V = 4.952 V
Calculating LSBs from a Given Error Budget
Formula
For a given prescaler range,
LSB count = ± (Input Voltage × Required % error) / (Equivalent voltage per LSB)
Example
Input Voltage = 3.3 V
Required error margin= 1%
Refer to Table 2-52 on page 2-126.
Equivalent voltage per LSB = 16 mV for a 16V prescaler, with ADC in 10-bit mode
LSB Count = ± (5.0 V × 1%) / (0.016)
LSB Count = ± 3.125
Equivalent voltage per LSB = 8 mV for an 8 V prescaler, with ADC in 10-bit mode
LSB Count = ± (5.0 V × 1%) / (0.008)
LSB Count = ± 6.25
The 8 V prescaler satisfies the calculated LSB count accuracy requirement (see Table 2-52 on
page 2-126).
2-128
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