XE8805 SEMTECH [Semtech Corporation], XE8805 Datasheet - Page 103

• Manufacturer Part Number: XE8805
• Description: Data Acquisition MCU
• Manufacturer: SEMTECH [Semtech Corporation]

where, from Eq. 10 and Eq. 11, the total PGA gain and offset are respectively:
and:
© Semtech 2006
Table 16-25. Last forced LSBs in conversion output registers for resolution settings smaller than 16
OUT
GD
GDoff
SET_OSR
TOT
[2:0]
ADC
000
001
010
011
100
101
110
111
TOT
=
Table 16-24. Basic ADC Relationships (example for: V
=
GD
=
2
GDoff
16
3
⋅
⋅
GD
V
SET_NELC = 00
V
REF
IN
3
2
+
⋅
1000000000
⋅
GD
⎛
⎜ ⎜
⎝
GD
GD
10000000
ADC Input
+2.49505V
+2.49497V
+76.145µV
-76.145µV
-2.49505V
-2.49513V
bits (n < 16) (RegAcOutMsb[7:0] & RegAcOutLsb[7:0])
Voltage
1
3
V
100000
TOT
⋅
IN,ADC
0V
GDoff
...
...
1000
−
10
GDoff
-
-
-
2
(V/V)
SET_NELC = 01
+0.5⋅FS
-0.5⋅FS
TOT
Scale
% of
(FS)
Full
...
...
...
...
...
...
0
100000000
⋅
V
(V/V)
V
1000000
REF
IN
10000
⎞
⎟ ⎟
⎠
100
Output in
⋅
=+32'767
=+32'766
16-17
=-32'767
=-32'768
OSR 1
1
-
-
-
+2
+2
LSBs
-2
OSR
-2
+1
...
-1
...
15
0
15
15
15
SET_NELC = 10
-1
-1
-2
+
10000000
Output
in Hex
100000
Code
7FFE
FFFF
7FFF
0001
0000
8001
8000
...
...
1000
(LSB) (Eq. 18)
REF
10
-
-
-
-
= 5V, OSR = 512, n = 16 bits)
SET_NELC = 11
1000000
10000
100
1
-
-
-
-
XE8805/05A
www.semtech.com