XE8000EV121 Semtech, XE8000EV121 Datasheet - Page 45

• Manufacturer Part Number: XE8000EV121
• Description: BOARD EVAL FOR SX8723/24
• Manufacturer: Semtech

Specifications of XE8000EV121

• Main Purpose: Interface, Sensor to ADC Interface, Programmable
• Embedded: No
• Utilized Ic / Part: SX8723, SX8724, SX8725
• Primary Attributes: Signal Conditioning for Bridge-Type Sensors
• Secondary Attributes: GUI, Up to 16-Bit, Programmable Gain of 1/12 ~ 1000, I2C Interface
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

ADVANCED COMMUNICATIONS & SENSING
As an example, consider the system where: GD
V
we get: V
ADC. Considering 0.2 V (rms) maximum signal amplitude, the signal-to-noise ratio is 90dB.
Noise can also be reduced by implementing a software filter. By making an average on a number of subsequent
measurements, the apparent noise is reduced the square root of the number of measurement used to make the
average.
V1.8 © 2009 Semtech Corp.
REF
= 5 V. In this case, the noise contribution V
N,IN
= 6.4 µV (rms) at the input of the acquisition chain, or, equivalently, 0.85 LSB at the output of the
V
N,IN
Figure 24 - ADC Noise (PGA1, 2 & 3 Bypassed, OSR = 512, N
GD1
PGA1
GD1
PGA1
Figure 25 - Simple Noise Model for PGAs and ADC
V
N1
Figure 26 - Total Input Referred Noise
V
80
60
40
20
0
N1
-5
ZoomingADC™ for Pressure and Temperature Sensing
-4
GD2
Output Code Deviation From Mean Value [LSB]
PGA2
GD2
-3
PGA2
N1
2
-2
= 10 (GD
of PGA1 is dominant over that of PGA2. Using Equation 25,
V
45
-1
N2
V
N2
0
1
1
GD3
= 1; PGA3 bypassed), OSR = 512, N
PGA3
GD3
PGA3
2
3
V
4
N3
V
N3
5
ELCONV
ADC
f
s
ADC
f
s
= 2)
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SX8725
ELCONV
= 2,