M1AFS250-FGG256I Actel Corporation, M1AFS250-FGG256I Datasheet - Page 142

• Manufacturer Part Number: M1AFS250-FGG256I
• Description: Actel Fusion Family Of Mixed Signal Fpgas
• Manufacturer: Actel Corporation

Device Architecture
Table 2-50 • Analog Channel Accuracy: Monitoring Standard Positive Voltages
2- 12 6
Input Voltage
(V)
15
14
12
5
3.3
2.5
1.8
1.5
1.2
0.9
Notes:
1. Requires enabling Analog Calibration using SmartGen Analog System Builder. For further details, refer to the
2. Direct ADC mode using an external VAREF of 2.56V±4.6mV, without Analog Calibration macro.
3. For input greater than 2.56 V, the ADC output will saturate. A higher VAREF or prescaler usage is recommended.
"Temperature, Voltage, and Current Calibration in Fusion FPGAs" chapter of the
Typical Conditions, T
Examples
Calculating Accuracy for an Uncalibrated Analog Channel
For a given prescaler range,
where
Formula
Channel Output offset in V = Channel Output offset in LSBs x Equivalent voltage per LSB
Channel Gain Factor = 1+ (% Channel Gain / 100)
Example
Input Voltage = 5 V
Chosen Prescaler range = 8 V range
Refer to
Max. Output Voltage = (Max Positive output offset) + (Input Voltage x Max Gain Factor)
Max. Positive output offset = (8 LSB) x (8mV per LSB in 10-bit mode)
Max. Positive output offset = 64 mV
Max. Gain = 1 + (2/100)
Max. Gain = 1.02
Max. Output Voltage = (64 mV) + (5 V x 1.02)
Max. Output Voltage = 5.164 V
Similarly,
16 V (AT)
1
1
1
2
2
3
4
5
7
9
Calibrated Typical Error per Positive Prescaler Setting
Output Voltage = (Channel Output Offset in V) + (Input Voltage x Channel Gain)
Table 2-48 on page
16 V (12 V)
(AV/AC)
1
2
2
2
4
5
6
9
A
= 25°C
EQ 24
(AV/AC)
8 V
2-124.
1
1
1
1
2
2
4
gives the output voltage.
4 V (AT)
1
1
1
2
2
3
R e visio n 1
(AV/AC)
4 V
1
1
1
2
2
3
(AV/AC)
2 V
1
1
1
1
Fusion FPGA Fabric User’s
1
(%FSR)
(AV/AC)
1 V
1
VAREF = 2.56 V
Direct ADC
(%FSR)
Guide.
1
1
1
1
1
EQ 24
2,3