XE88LC05MI000 ETC1 [List of Unclassifed Manufacturers], XE88LC05MI000 Datasheet - Page 19

• Manufacturer Part Number: XE88LC05MI000
• Description: 16 + 10 bit Data Acquisition Ultra Low-Power Microcontroller
• Manufacturer: ETC1 [List of Unclassifed Manufacturers]

8 ZoomingADC
8.1 PGA 1
Table 8.1:
Note:
Figure 8.1:
19
GD_preci
symbol
GD_TC
Zin1p
GD1
Zin1
VN1
fs
Temperature dependency of gain settings
AC_R(0)
AC_R(1)
AC_R(2)
AC_R(3)
AC_A(0)
AC_A(1)
AC_A(2)
AC_A(3)
AC_A(4)
AC_A(5)
AC_A(6)
AC_A(7)
The fully differential acquisition chain is formed of a programmable gain (0.5 - 1000) and offset
amplifier and a programmable speed and resolution ADC (example: 12 bits at 4 kHz, 16 bits
at 1 kHz). It can handle inputs with very low full scale signal and large offsets.
Input selection is made from 1 of 4 differential pair or 1 of seven single signal versus AC_A(0).
Reference is chosen from the 2 differential references.
The gain of each amplifier is programmed individually. Each amplifier is powered on and off on
command to minimize the total current requirement. All blocks can be set to low frequency op-
eration and lower their current requirement by a factor 2 or 4.
The ADC can run continuously (end of conversion signalled by an interrupt, event or by pooling
the ready bit), or it can be started on request.
PGA1 Performances
1) Measured with block connected to inputs through AMUX block. Normalized input sampling
frequency for input impedance is 512 kHz. This figure has to be multiplied by 2 for fs = 256 kHz
and 4 for fs = 128 kHz.
2) Input referred rms noise is 205 uV per input sample with gain = 1, 20.5 uV with gain = 10.
This corresponds to 28.6 nV/sqrt(Hz) for fs = 512 kHz and gain = 10.
Acquisition channel block diagram
Input impedance for gain 1
Precision on gain settings
input sampling frequency
Input referred noise
PGA1 Signal Gain
Input impedance
description
input selection
reference selection
gain1
Data Acquisition Microcontroller
offset2
gain2
1500
min
150
-5
-5
1
28.6
typ
offset3
gain3
max
512
10
+5
+5
mode
sqrt(Hz)
ppm/°C
unit
kHz
nV/
kΩ
kΩ
%
-
ADC
output
code
XE88LC05
GD1 = 1 or 10
Comments
1
1
2
D0109-40