SX8722I070LF SEMTECH [Semtech Corporation], SX8722I070LF Datasheet - Page 32

• Manufacturer Part Number: SX8722I070LF
• Description: High gain acquisition for sensor interface
• Manufacturer: SEMTECH [Semtech Corporation]

9.5. Offset cancellation
9.5.1. Overview
The offset cancellation consists in adding or subtracting a fraction or a multiple of the reference to the signal before the ADC
input.
In the predefined settings only the addition or the subtraction of VREF/2 is implemented.
More offsets configuration can be defined using the "advanced configuration" at the end of this document.
The drawings below explain the offset concept.
ACS - Revision 4.2
©2008 Semtech Corp.
ADVANCED COMMUNICATIONS & SENSING
A
- Vref / 2
AC
AR
Vref / 2
(AC1 – AC0)
0
0
1
2
3
4
5
6
7
0
1
2
3
V
IN
C
B
f
S
V
REF
Figure 18. Offset cancellation in the acquisition chain
October 2008
+
-
PGA1
1 - 10
+
-
OFF2
+
-
-5/5
5/5
...
1 - 2 - 5 - 10
Figure 19. Differential signal
PGA2
t
+
-
Page 32
GAIN x2
+
+
-
-
0/12 to 127/12
PGA3
OFF3
-63/12
63/12
High gain acquisition for sensor interface
...
- Vref / 2
+
Vref / 2
-
Vin ADC
0
V
+
-
IN, ADC
D
ADC
f
S
E
MEASUREMENT
DATASHEET
www.semtech.com
SX8722
ENGINE
t