Table 3-6. bipolar code table (pga gain = 1) -24, Table 3-7. bipolar input scaling -24, Table 3-6. bipolar code table (pga gain = 1) – Maxim Integrated MAXQ7666 User Manual
Page 114: Table 3-7. bipolar input scaling
MAXQ7665/MAXQ7666 User’s Guide
3-24
Table 3-6. Bipolar Code Table (PGA Gain = 1)
Table 3-7 shows the input range for various PGA settings (PGG2:PGG0) in bipolar mode. When the PGA is used (gain > 1), the differ-
ential input range at the analog multiplexer input is reduced by the gain factor:
full-scale differential input range = ±REFADC / (2 x PGA gain factor)
Table 3-7. Bipolar Input Scaling
The differential analog input voltage as a function of REFADC, PGA gain factor (PGA_GF), and the ideal (error-free) digital output code
are determined with the following equation:
ΔV
AIN
= LSB x CODE
12
± 0.5 x LSB
Where:
ΔV
AIN
= V
AIN+
- V
AIN-
LSB = REFADC / (PGA_GF x 2
12
) = REFADC / (PGA_GF x 4096)
CODE
12
= the decimal equivalent of the digital output code (see Table 3-4 and Table 3-6)
PGA_GF = PGA gain factor (1, 2, 4, 8, 16, or 32)
±0.5 x LSB represents the quantization error that is inherent to any ADC
When using a 4.096V reference and a PGA gain factor of 1, 1 LSB equals 1.0mV. When using a 5.0V reference and a PGA gain factor
of 1, 1 LSB equals 1.22mV.
BINARY DIGITAL OUTPUT CODE
ADCD11:ADCD0
HEXADECIMAL EQUIVALENT OF
ADCD11:ADCD0
DECIMAL EQUIVALENT OF
ADCD11:ADCD0 (CODE12)
IDEAL DIFFERENTIAL INPUT
VOLTAGE (V)
(REFADC = 5.0V)
0111 1111 1111
0x7FF
+2047
+2.49878 ± 0.5 LSB
0111 1111 1110
0x7FE
+2046
+2.49756 ± 0.5 LSB
0000 0000 0001
0x001
+1
+0.00122 ± 0.5 LSB
0000 0000 0000
0x000
0
0.000 ± 0.5 LSB
1111 1111 1111
0xFFF
-1
-0.00122
± 0.5 LSB
1000 0000 0001
0x801
-2047
-2.49878 ± 0.5 LSB
1000 0000 0000
0x800
-2048
-2.5 ± 0.5 LSB
PGG2
PGG1 PGG0
GAIN
FACTOR
DIFFERENTIAL
INPUT RANGE AT
MUX INPUTS
DIFFERENTIAL INPUT RANGE
WITH 5.0V EXTERNAL
REFERENCE
LSB SIZE WITH 5.0V
EXTERNAL
REFERENCE
OUTPUT CODE
RANGE (DECIMAL)
0 0 0 x1 ±REFADC/2
-2.5V
to
2.5V
1.22mV
0
0
1
x2
±REFADC/4
-1.25V to 1.25V
610.35μV
0
1
0
x4
±REFADC/8
-0.625V to 0.625V
305.18μV
0
1
1
x8
±REFADC/16
-0.313V to 0.313V
152.59μV
1 0 0 x16 ±REFADC/32
-0.156V
to
0.156V
76.29μV
1 0 1 x32 ±REFADC/64
-0.078V
to
0.078V
38.15μV
-2048 to +2047
Maxim Integrated