TPCE636 User Manual Issue 1.0.2
Page 59 of 104
Serial ADC Interface
7.9
7.9.1 Overview
The 16 analog inputs of the TPCE636 are realized with 8 LTC2323-16 ADC devices. Each of these SAR-
ADCs has two ADC channels. Thus, a total of 16 ADC channels are available on the TPCE636.
A coarse overview of the analog input section of the TPCE636 is shown by the following figure:
Figure 7-6 : Analog Input Section
The key-features of the LTC2323-16 are:
Dual Channel - SAR-ADC
16bit resolution
5Msps Throughput Rate for each Channel
LVDS SPI-Compatible Serial Interface to User FPGA (Kintex-7)
In order to adapt the LTC2323-16 to a ±10V input voltage on each input-pin (±20V differential voltage range)
two stage input operational amplifiers for input impedance conversion and gain adaption are used in addition
to the ADC.
The following figure shows the structure and principle of two ADC inputs. Both are connected via impedance
converter and level adjustment to the LTC2323-16 dual ADC.
Figure 7-7 : Analog Input Block Diagram
To minimize power requirement, unnecessary temperature rise and signal interference, unused
ADC inputs should be set to 0V differential or GND.
F
ro
n
t
I/
O
F
ro
n
t
I/
O
Impedance
Converter
Impedance
Converter
Impedance
Converter
Impedance
Converter
Divider
and
Filter
Divider
and
Filter
Divider
and
Filter
Divider
and
Filter
Differential
ADC
LTC2323-16
Differential
ADC
LTC2323-16
FPGA
Kintex-7
FPGA
Kintex-7
2.5V LVDS
Channel 1
Channel 2