Texas Instruments ADC12EU050: Ultra-low Power, Octal, 12-bit, 45 MSPS Sigma-Delta Analog-to-Digital Converter Evaluation Board Texas Instr ADC12EU050EB/NOPB 数据表
产品代码
ADC12EU050EB/NOPB
Functional Description
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Functional Description
The ADC12EU050 Evaluation Board schematic is shown in
. A list of default switch and jumper
settings can be found in
.
3.1
Analog Input
The analog input is supplied through standard SMA connectors. The evaluation board is designed for
single ended inputs, which are converted to differential by the transformers.
single ended inputs, which are converted to differential by the transformers.
It must be ensured that a high quality signal source is used so that the ADC dynamic performance can be
properly evaluated. A bandpass filter on the input signal is highly recommended.
properly evaluated. A bandpass filter on the input signal is highly recommended.
3.2
ADC Reference
The ADC12EU050 can use an internal or external reference. This evaluation board is configured to use
the internal reference.
the internal reference.
3.3
ADC Input Clock
The ADC12EU050 can only be clocked at 45MHz. The input clock circuit is shown in
.
Figure 2. Input clock circuit
Select “External Clock” with switch S2 which disables the on-board crystal oscillator. It enables the user to
connect a single ended clock to P11. This clock is converted to a differential signal by the transformer T9.
connect a single ended clock to P11. This clock is converted to a differential signal by the transformer T9.
Selecting “On Board Clock” with switch S2 is not supported unless a 45MHz Crystal Oscillator is
populated at IC1.
populated at IC1.
The external clock amplitude and waveform are fairly flexible, but a 600mVpp differential square wave at
the chip inputs is recommended.
the chip inputs is recommended.
By changing the 0 ohm resistors R24, R25, R28 and R29 other clock input configurations can be realized.
For example, a fully differential clock could be supplied, bypassing the on-board transformer.
For example, a fully differential clock could be supplied, bypassing the on-board transformer.
If a single ended clock is supplied to the ADC, then the LVDS termination resistor, R26, must be removed.
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SNAU020 – September 2013
ADC12EU050: Ultra-low Power, Octal, 12-bit, 45MSPS Sigma-Delta Analog-
to-Digital Converter
Copyright © 2013, Texas Instruments Incorporated