DA6505.005
11 June 2018
APPLICATION INFORMATION
Table 17 shows an example of calculated minimum and maximum differential signal values at the sensor input
based on both full and linear input signal ranges of the ADC using the equations 3, 4, 7 and 8. The table shows
input signal values at all eight offset options at both offset polarity signs. The table values are for unity gain
amplification setting (GAIN=1). The input signal values for other gain settings can be easily calculated simply by
dividing these values by the other gain setting value.
Table 17. Min and max input signal values in overall and linear input signal ranges for GAIN=1 setting
OFS%
[% of ISRADC]
VINMIN
[mV]
VINMAX
[mV]
VINLINMIN
[mV]
VINLINMAX
[mV]
-49 %
-42 %
-35 %
-28 %
-21 %
-14 %
-7 %
-1386
-1288
-1190
-1092
-994
-896
-798
-700
-602
-504
-406
-308
-210
-112
-14.0
14
112
210
308
406
504
602
700
798
896
994
1092
1190
1288
1386.0
-1246
-1148
-1050
-952
-854
-756
-658
-560
-462
-364
-266
-168
-70
-126
-28
70
168
266
364
462
560
658
756
854
952
1050
1148
1246.0
0 %
7 %
14 %
21 %
28 %
35 %
42 %
49 %
28
126.0
Pressure Measurement Configuration
A piezoresistive absolute pressure sensor can be modeled roughly with the following signal voltage characteristic
when including only first order pressure and temperature characteristics.
FS
(
1+TCFS
(
T −TREF ))
VDDS
VDDREF
Equation 16
VIN
(
p,T
)
=
p +OS
(
1+TCOS
(
T −TREF ))
pFS
VDDS = sensor supply voltage; 1.68V typ
OS = zero pressure offset [V]
VDDREF = reference supply voltage at which the
sensor parameters (FS, OS) have been specified
(often 5V)
p = pressure [bar]
pFS = full-scale pressure range [bar]
FS = full-scale span [V]
TCFS = full-scale span temperature coefficient
[ppm/C]
TCOS = offset temperature coefficient [ppm/C]
TREF = reference temperature for resistor values [C]
T = actual temperature to be measured [C]
The above linear approximation includes sensor full-scale span and offset signal temperature dependencies.
38 (44)
MAS [ MICRO ANALOG SYSTEMS ]
