SX8724C Datasheet, PDF (34/67 Pages) Semtech Corporation – ZoomingADC for sensing data acquisition

SX8724C
ZoomingADC for sensing data acquisition
ADVANCED COMMUNICATIONS & SENSING
DATASHEET
where, from Equation 11 and Equation 12, the total PGA gain and offset are respectively:
GD_TOT = GD₃ ⋅ GD₂ ⋅ GD₁
Equation 20
and:
GDoff_TOT = GDoff₃ + GD₃ ⋅ GDoff₂
Equation 21
Table 19. Basic ADC Relationships (example for: VREF = 5V, OSR = 512, n = 16bits)
ADC Input Voltage
V_IN,ADC
+2.49505 V
+2.49497 V
...
+76.145 μV
0
-76.145 μV
...
-2.49505 V
-2.49513 V
% of Full Scale (FS)
+0.5 x FS
...
...
...
0
...
...
...
-0.5 x FS
Output in LSBs
+2¹⁵-1 = 32’767
+2¹⁵-2 = 32’766
...
+1
0
-1
...
-2¹⁵-1 = -32’767
-2¹⁵ = -32’768
Hexadecimal Output Code
7FFF
7FFE
...
0001
0000
FFFF
...
8001
8000
Table 20. Last forced LSBs in conversion output register for resolution settings smaller than 16bits¹
SetOsr[2:0]
SetNelconv = ‘00’
SetNelconv = ‘01’
‘000’
1000000000
100000000
‘001’
10000000
1000000
‘010’
100000
10000
‘011’
1000
100
‘100’
10
1
‘101’
-
-
‘110’
-
-
‘111’
-
-
1. (n<16) (RegACOutMsb[7:0] & RegACOutLsb[7:0])
SetNelconv = ‘10’
10000000
100000
1000
10
-
-
-
-
SetNelconv = ‘11’
1000000
10000
100
1
-
-
-
-
Revision 1.01
© Semtech
January 2011
Page 34
www.semtech.com/products/